Lu Wang, Jinge Yao, Haikuo Zhang et al.

Frontiers in Marine Science • 2023

The shipping industry plays a vital role in the world trading system and in maintaining the stability of global supply chains. However, we cannot ignore the damage it brings to the marine environment. With a focus on protecting the marine environment, the sustainable development of shipping companies has also drawn growing attention. This study examines the sustainable shipping management practice system and develops a comprehensive framework to evaluate the significance of influencing elements and prioritizes those factors. This paper adopts a fuzzy analytic hierarchy process method. It establishes a total of 11 sub-index systems from three aspects: the external policy pressure of shipping companies, the ecological design of shipping services, and the cross-functional green management within shipping companies. We used the fuzzy analytic hierarchy process (FAHP) to analyze data collected from 37 experts in the Chinese shipping industry. The findings show that external policy pressure is the most critical factor influencing sustainable shipping management, followed by eco-design and cross-functional green management. These factors have a big impact and provide management references for shipping company managers and policymakers. They also give the government a company perspective when creating pertinent regulations.

C. Cruz Viggi, E. Presta, M. Bellagamba et al.

Frontiers in Microbiology • 2015

This study presents the proof-of-concept of the “Oil-Spill Snorkel”: a novel bioelectrochemical approach to stimulate the oxidative biodegradation of petroleum hydrocarbons in sediments. The “Oil-Spill Snorkel” consists of a single conductive material (the snorkel) positioned suitably to create an electrochemical connection between the anoxic zone (the contaminated sediment) and the oxic zone (the overlying O2-containing water). The segment of the electrode buried within the sediment plays a role of anode, accepting electrons deriving from the oxidation of contaminants. Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water. Here we report the results of lab-scale microcosms setup with marine sediments and spiked with crude oil. Microcosms containing one or three graphite snorkels and controls (snorkel-free and autoclaved) were monitored for over 400 days. Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls. Accordingly, the initial rate of total petroleum hydrocarbons (TPH) degradation was also substantially enhanced. Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 ± 1% (p = 0.004) and 21 ± 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively. Although, the “Oil-Spill Snorkel” potentially represents a groundbreaking alternative to more expensive remediation options, further research efforts are needed to clarify factors and conditions affecting the snorkel-driven biodegradation processes and to identify suitable configurations for field applications.

E. Gambino, K. Chandrasekhar, R. A. Nastro

Environmental Science and Pollution Research • 2021

Marine pollution is becoming more and more serious, especially in coastal areas. Because of the sequestration and consequent accumulation of pollutants in sediments (mainly organic compounds and heavy metals), marine environment restoration cannot exempt from effective remediation of sediments themselves. It has been well proven that, after entering into the seawater, these pollutants are biotransformed into their metabolites, which may be more toxic than their parent molecules. Based on their bioavailability and toxic nature, these compounds may accumulate into the living cells of marine organisms. Pollutants bioaccumulation and biomagnification along the marine food chain lead to seafood contamination and human health hazards. Nowadays, different technologies are available for sediment remediation, such as physicochemical, biological, and bioelectrochemical processes. This paper gives an overview of the most recent techniques for marine sediment remediation while presenting sediment-based microbial fuel cells (SMFCs). We discuss the issues, the progress, and future perspectives of SMFC application to the removal of hydrocarbons and metals in the marine environment with concurrent energy production. We give an insight into the possible mechanisms leading to sediment remediation, SMFC energy balance, and future exploitation.

Haiman Wang, Yeting Zhang, Guiqiang Wang

Advances in Transdisciplinary Engineering • 2022

Continuous stirred bioelectrochemical system (CSBES), consisting of anaerobic digestion reaction zone (ADRZ) and bioelectrochemical reaction zone (BERZ), was constructed to investigate the ammonia inhibitory effects on the performance of electricity generation and wastewater treatment. Continuous experiments were conducted with ammonia concentration ranging from 300 mg/L to 1200 mg/L. As the ammonia concentration increasing from 300 mg/L to 900 mg/L, both of the maximum power densities and the COD removal increased. When the ammonia concentration reached to 1200 mg/L, the maximum power densities of the four cells decreased by 55.7%, 58.9%, 58.0% and 60.6% in comparison with that under ammonia concentration of 900 mg/L. The COD removal reduced to 71.2 ± 1.4%, leading to COD concentration in the effluent increased to 1758 ± 93 mg/L. Electrochemical measurements revealed that the deterioration of anode performance caused the reduction of power generation. The conductivity control experiment showed that the toxic effects of high ammonia concentration on exoelectrogens caused performance deterioration of the CSBES. The threshold ammonia concentration that triggered the inhibition effect on exoelectrogens in CSBES was 1200 mg/L, and the anaerobic consortium in ADRZ could tolerant to higher ammonia concentration than the exoelectrogens in BERZ.

Youzhao Wang, Yuan Pan, Xianjin Li et al.

Water Environment Research • 2019

Abstract Excess sludge contains a large amount of organic matter, most of which is present in the form of bacteria and extracellular polymeric substances. In this study, a photosynthetic bioelectrochemical system ( BES ) combined with ultrasonic treatment ( UT ) was investigated to mineralize sludge. The sludge was disintegrated by the UT , and the supernatant separated from the treated sludge was further degraded through a bioelectrochemical system containing photosynthetic bacteria ( PSB ‐ BES ). The UT efficiency was enhanced by supernatant separation. The PSB ‐ BES method effectively improved the degradation of the soluble chemical oxygen demand ( SCOD ) from the supernatant. The SCOD and protein removal were increased 1.4 and 1.5 times, respectively, compared to BES without PSB . In addition, the effects of several key operating factors including illumination, voltage, and temperature were systematically investigated. This study provides a basis for further development of sludge mineralization processes. Practitioner points The sludge was disintegrated by the ultrasound treatment. The supernatant separated from treated sludge was further degraded by a bioelectrochemical system combined with photosynthetic bacteria. The ultrasonic treatment efficiency was enhanced by supernatant separation. The PSB‐BES method effectively improved the soluble chemical oxygen demand (SCOD) degradation from the supernatant. The effects of several key operating factors including light (dark–photo), voltage, and temperature were systematically investigated.

Long Chen, Yanli Guo, Shaohui Zhang et al.

Water Environment Research • 2023

Abstract Bioelectrochemical system is a novel method for controlling down nitrate pollution, yet the feasibility of using methane as the electron donors for denitrification in this system remains unknown. In this study, using the effluent from mother BESs as inocula, a denitrifying anaerobic methane oxidation bioelectrochemical system was successfully started up in 92 days. When operated with 50 mmol/L phosphate buffer solution at pH 7 and 30°C, the maximum methane consumption, nitrate, and total nitrogen removal load reached 0.23 ± 0.01 mmol/d, 551.0 ± 22.1 mg N/m 3 /d, and 64.0 ± 18.8 mg N/m 3 /d, respectively. Meanwhile, the peak voltage of 93 ± 4 mV, the anodic coulombic efficiency of 6.99 ± 0.20%, and the maximum power density of 219.86 mW/m 3 were obtained. The metagenomics profiles revealed that the dominant denitrifying bacteria in the cathodic chamber reduced most nitrate to nitrite through denitrification and assimilatory reduction. In the anodic chamber, various archaea including methanotrophs and methanogens converted methane via reverse methanogenesis to form formate (or H 2 ), acetate, and methyl compounds, which were than utilized by electroactive bacteria to generate electricity. Practitioner Points A denitrifying anaerobic methane oxidation BES was successfully started up in 92 d. Simultaneous removal of methane and nitrate was achieved in the DAMO‐BES. Functional genes related to AMO and denitrification were detected in the DAMO‐BES. Methylocystis can mediate AMO in the anode and denitrification in the cathode.

C. McCann, Matthew John Wade, N. Gray et al.

Frontiers in Microbiology • 2016

The High Arctic is dominated by polar desert habitats whose microbial communities are poorly understood. In this study, we used next generation sequencing to describe the α- and β-diversity of microbial communities in polar desert soils from the Kongsfjorden region of Svalbard. Ten phyla dominated the soils and accounted for 95% of all sequences, with the Proteobacteria, Actinobacteria, and Chloroflexi being the major lineages. In contrast to previous investigations of Arctic soils, relative Acidobacterial abundances were found to be very low as were the Archaea throughout the Kongsfjorden polar desert landscape. Lower Acidobacterial abundances were attributed to characteristic circumneutral soil pHs in this region, which has resulted from the weathering of underlying carbonate bedrock. In addition, we compared previously measured geochemical conditions as possible controls on soil microbial communities. Phosphorus, pH, nitrogen, and calcium levels all significantly correlated with β-diversity, indicating landscape-scale lithological control of available nutrients, which in turn, significantly influenced soil community composition. In addition, soil phosphorus and pH significantly correlated with α-diversity, particularly with the Shannon diversity and Chao 1 richness indices.

A. Šťovíček, Minsu Kim, D. Or et al.

Scientific Reports • 2017

Life in desert soil is marked by episodic pulses of water and nutrients followed by long periods of drought. While the desert flora and fauna flourish after rainfall the response of soil microorganisms remains unclear and understudied. We provide the first systematic study of the role of soil aqueous habitat dynamics in shaping microbial community composition and diversity. Detailed monitoring of natural microbial communities after a rainfall event revealed a remarkable decrease in diversity and a significant transition in community composition that were gradually restored to pre-rainfall values during soil desiccation. Modelling results suggest a critical role for the fragmented aqueous habitat in maintaining microbial diversity under dry soil conditions and diversity loss with wetting events that increase connectivity among habitats. This interdisciplinary study provides new insights into wetting and drying processes that promote and restore the unparalleled microbial diversity found in soil.

R. Marasco, Maria J Mosqueira, M. Fusi et al.

Microbiome • 2018

The rhizosheath-root system is an adaptive trait of sandy-desert speargrasses in response to unfavourable moisture and nutritional conditions. Under the deserts’ polyextreme conditions, plants interact with edaphic microorganisms that positively affect their fitness and resistance. However, the trophic simplicity and environmental harshness of desert ecosystems have previously been shown to strongly influence soil microbial community assembly. We hypothesize that sand-driven ecological filtering constrains the microbial recruitment processes in the speargrass rhizosheath-root niche, prevailing over the plant-induced selection. Bacterial and fungal communities from the rhizosheath-root compartments (endosphere root tissues, rhizosheath and rhizosphere) of three Namib Desert speargrass species (Stipagrostis sabulicola, S. seelyae and Cladoraphis spinosa) along with bulk sand have been studied to test our hypothesis. To minimize the variability determined by edaphic and climatic factors, plants living in a single dune were studied. We assessed the role of plant species vs the sandy substrate on the recruitment and selection, phylogenetic diversity and co-occurrence microbial networks of the rhizosheath-root system microbial communities. Microorganisms associated with the speargrass rhizosheath-root system were recruited from the surrounding bulk sand population and were significantly enriched in the rhizosheath compartments (105 and 104 of bacterial 16S rRNA and fungal ITS copies per gram of sand to up to 108 and 107 copies per gram, respectively). Furthermore, each rhizosheath-root system compartment hosted a specific microbial community demonstrating strong niche-partitioning. The rhizosheath-root systems of the three speargrass species studied were dominated by desert-adapted Actinobacteria and Alphaproteobacteria (e.g. Lechevalieria, Streptomyces and Microvirga) as well as saprophytic Ascomycota fungi (e.g. Curvularia, Aspergillus and Thielavia). Our results clearly showed a random phylogenetic turnover of rhizosheath-root system associated microbial communities, independent of the plant species, where stochastic factors drive neutral assembly. Co-occurrence network analyses also indicated that the bacterial and fungal community members of the rhizosheath-root systems established a higher number of interactions than those in the barren bulk sand, suggesting that the former are more stable and functional than the latter. Our study demonstrates that the rhizosheath-root system microbial communities of desert dune speargrasses are stochastically assembled and host-independent. This finding supports the concept that the selection determined by the desert sand prevails over that imposed by the genotype of the different plant species.

G. Uritskiy, A. Munn, Micah Dailey et al.

Frontiers in Microbiology • 2020

Spatial heterogeneity in microbial communities is observed in all natural ecosystems and can stem from both adaptations to local environmental conditions as well as stochastic processes. Extremophile microbial communities inhabiting evaporitic halite nodules (salt rocks) in the Atacama Desert, Chile, are a good model ecosystem for investigating factors leading to microbiome heterogeneity, due to their diverse taxonomic composition and the spatial segregation of individual nodules. We investigated the abiotic factors governing microbiome composition across different spatial scales, allowing for insight into the factors that govern halite colonization from regional desert-wide scales to micro-scales within individual nodules. We found that water availability and community drift account for microbiome assembly differently at different distance scales, with higher rates of cell dispersion at the smaller scales resulting in a more homogenous composition. This trend likely applies to other endoliths, and to non-desert communities, where dispersion between communities is limited. At the intra-nodule scales, a light availability gradient was most important in determining the distribution of microbial taxa despite intermixing by water displacement via capillary action.

D. Schulze‐Makuch, D. Wagner, S. Kounaves et al.

Proceedings of the National Academy of Sciences • 2018

Significance It has remained an unresolved question whether microorganisms recovered from the most arid environments on Earth are thriving under such extreme conditions or are just dead or dying vestiges of viable cells fortuitously deposited by atmospheric processes. Based on multiple lines of evidence, we show that indigenous microbial communities are present and temporally active even in the hyperarid soils of the Atacama Desert (Chile). Following extremely rare precipitation events in the driest parts of this desert, where rainfall often occurs only once per decade, we were able to detect episodic incidences of biological activity. Our findings expand the range of hyperarid environments temporarily habitable for terrestrial life, which by extension also applies to other planetary bodies like Mars. Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today’s extreme hyperaridity.

Jill A. Sohm, T. D. Niederberger, A. Parker et al.

Frontiers in Microbiology • 2020

Cyanobacterial mats in the Antarctic Dry Valleys are photosynthetic microbial ecosystems living at the extreme of conditions on Earth with respect to temperature, light, water and nutrient availability. They are metabolically active for about 8 weeks during the austral summer when temperatures briefly rise above freezing and glacial and lake melt waters are available. There is much to learn about the biogeochemical impact of mats in these environments and the microbial communities associated with them. Our data demonstrate that these mats attain surprisingly high rates of carbon (CO2) and dinitrogen (N2) fixation when liquid water is available, in some cases comparable to rates in warmer temperate or tropical environments. C and N2 fixation in Dry Valley mats in turn substantially elevate dissolved organic C and inorganic N pools and thereby promote enhanced microbial secondary production. Moreover, the microbial community fingerprint of these mats is unique compared with the more ubiquitous dry soils that do not contain mats. Components of the heterotrophic microbiota may also contribute substantially to N inputs through N2 fixation.

Joseph Frazer Banda, Yanchun Lu, Chun-bo Hao et al.

Geomicrobiology Journal • 2020

Abstract The Badain Jaran Desert (BJD) is characterized by extremely arid conditions. Counterintuitively, this arid region has over 100 permanent lakes. To date, only a few studies have characterized microbial community in these lakes. Our investigation sampled five lakes with salinity (2.1–397.33 g/L) and pH (9.69–10.83) gradients, of which one was low salinity (< 3.0 g/L), three were moderately saline (50–250 g/L) and the other one was hypersaline (>250.0 g/L). Using high-throughput sequencing of 16S rRNA genes, we noted a significant difference in microbial communities inhabiting the different alkali-saline lakes. Generally, bacteria were predominant in the low and moderately saline lakes, while archaea were dominant in the hypersaline lake. The low salinity lake exhibited the highest microbial diversity, dominated by Burkholderia and Halomonas. Spiribacter and Halomonas dominated the moderately saline lakes, while Halohasta and Halosimplex dominated the hypersaline lake. pH was a primary driver of microbial richness, whereas salinity was the predominant factor controlling microbial community composition. Therefore, both pH and salinity shaped the haloalkaliphilic community in the soda lakes. Furthermore, it was found that many haloalkaliphiles such as Spiribacter and Halomonas survived beyond their pH and salinity limits, suggesting that there could be more new species in these soda lakes.

Zhihao Zhang, Xutian Chai, A. Tariq et al.

Frontiers in Microbiology • 2021

Intercropping is an important practice in promoting plant diversity and productivity. Compared to the accumulated understanding of the legume/non-legume crop intercrops, very little is known about the effect of this practice when applied to native species on soil microbial communities in the desert ecosystem. Therefore, in the present study, bulk soil and rhizosphere microbial communities in the 2-year Alhagi sparsifolia (legume)/Karelinia caspica (non-legume) monoculture vs. intercropping systems were characterized under field conditions. Our result revealed that plant species identities caused a significant effect on microbial community composition in monocultures but not in intercropping systems. Monoculture weakened the rhizosphere effect on fungal richness. The composition of bacterial and fungal communities (β-diversity) was significantly modified by intercropping, while bacterial richness (Chao1) was comparable between the two planting patterns. Network analysis revealed that Actinobacteria, α- and γ-proteobacteria dominated bulk soil and rhizosphere microbial co-occurrence networks in each planting pattern. Intercropping systems induced a more complex rhizosphere microbial community and a more modular and stable bulk soil microbial network. Keystone taxa prevailed in intercropping systems and were Actinobacteria-dominated. Overall, planting patterns and soil compartments, not plant identities, differentiated root-associated microbiomes. Intercropping can modify the co-occurrence patterns of bulk soil and rhizosphere microorganisms in desert ecosystems. These findings provided a potential strategy for us to manipulate desert soil microbial communities and optimize desert species allocation in vegetation sustainability.

A. Faraz

Pakistan Journal of Agricultural Sciences • 2018

Camels are very well adapted to their native environment and can sustain life in hot and harsh deserts. The dromedary camel is a best source of meat and milk especially for those areas where production performance of other animals is adversely affected by the harsh environmental conditions. This mainly is due to its unique physiological characteristics that enable him to face higher temperatures, solar radiations, water scarcity, poor vegetation and rough terrains. It has less competition with any domestic specie regarding feed and performance. It can thrive on horny plants, thorny bushes, salty leaves and can browse variety of forages. In the absence of quality forages, camel can utilize poor quality forages with much more efficiency as it can retain fiber in its fore stomach for as long as 70 hours. According to Schwartz et al. (1992) in contrast with other ruminants, when it is fed with low protein forage it has the capacity and efficiency of reutilizing the urea for microbial protein synthesis. Due to these attributes camel is considered as the animal with unfathomed potential to meet the future dietary and medical needs of human beings (Faye and Esenov, 2005). However, in spite of all these attributes, the camel has for long remained a neglected animal. In arid areas, camels constitute the most important source of meat. Mostly they are raised under traditional management systems as pastoralists are always moving in search of food and water over large areas for their camels (Omer et al., 2008). Camel is an indigenous genetic resource, it needs to be managed and preserved properly. It plays an indispensible role in the pastoral ecology. Different studies highlight its unique characteristics especially under stress environment. To meet the rapidly growing demands of exploding population, the strategic idea is to minimize the dependence on external food supply. There is need to recognize the place of camel in farm animals and to get increased output from indigenous natural resources that have not been exploited yet. Camel husbandry system is in a state of flux as pastoralists are deviating from their traditional management system to semi-intensive and intensive management system. This rapidly changing scenario needs overall evaluation and there is an urgent need to undertake multi-disciplinary studies. Camel plays an indispensible role in the social life and economy of the people of arid and semi-arid areas in various regions of the world. Despite of its significant contribution to the livelihood of pastoral society who does not have any alternate mode of production system, the camel is one of the Pak. J. Agri. Sci., Vol. 55(3), 621-628; 2018 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 DOI: 10.21162/PAKJAS/18.4631 http://www.pakjas.com.pk

Jianxin Wang, Jianing Zhu, Yusheng Li et al.

Scientific Reports • 2025

The bank slope structure of the open channel in the Xinjiang desert is affected by seasonal climate changes and water erosion, leading to lining cracking. This study identified the optimal culture conditions and mineralization factors for Sporosarcina pasteurii through strain cultivation and precipitation assays. Subsequently, 0.1~5.0 mm wide penetrating concrete cracks were prefabricated, and microbially induced calcium carbonate precipitation (MICP) repair tests were conducted over 16 cycles. These experiments included macroscopic performance evaluations, such as area repair rate, penetration resistance, and capillary water absorption tests, alongside microscopic analyses using X-ray diffraction and scanning electron microscopy. The results indicate that MICP technology effectively repairs narrow cracks, preserving crack surface integrity, significantly reducing permeability and water absorption, and enhancing the durability of the concrete. However, for cracks exceeding 1.0 mm in width, the repair efficiency declines progressively. Based on the experimental data, it is concluded that a crack width of 1.0 mm is the optimal threshold for effective MICP-based repair within 16 cycles, ensuring both structural integrity and optimal waterproofing. These results offer valuable insights into the potential application of MICP technology for the remediation of lining cracks in the bank slopes of water conveyance channels in Xinjiang Desert.

Marisela Aguirre Ramírez, P. U. Martínez-Pabello, María Colín-García et al.

Boletín de la Sociedad Geológica Mexicana • 2025

Arid and semi-arid desert areas characterized by extreme conditions, including northern Mexico, have rocks with micrometric coatings. These coatings are known as desert varnish, an often dark-red microlayer deposited over millennia and developed on different rock types. These microlaminations, rich in clay minerals and Fe- /Mn-oxides, can serve as habitats for various microorganisms, mainly fungi and bacteria. However, the role of microorganisms in these varnish formations is still under debate. In the Chihuahuan desert (Mexico), particularly in the Samalayuca ridge, extensive areas are covered by rocks with desert varnish Here we present a research effort focused on isolating Fe- and Mn-oxidising microorganisms in different culture media, along with directed sequencing. Using a benzidine spot test to detect oxidant species revealed the presence of bacteria and fungi inhabiting these layers. Likewise, we contribute to a better understanding of the formation of desert varnish, representing the first report of specific microorganisms isolated from rock vanish of the Chihuahuan desert.

Zhao Fang, Hailong Yu, Feng Jiao et al.

Land Degradation &amp; Development • 2025

The availability of nitrogen (N) and phosphorus (P) significantly influences microbial metabolism, thereby affecting soil carbon (C) sequestration. However, it remains unclear how microbial resource limitation and C turnover dynamics respond to P availability under elevated N loads in dryland ecosystems. To address this, we conducted a 7‐year experiment in a desert steppe in northern China, applying a gradient of P additions (0–16 g P m−2 year−1) under conditions of N loading (atmospheric N deposition +5 g N m−2 year−1). Our aim was to investigate microbial nutrient limitations and their impact on microbial carbon use efficiency (CUE) based on stoichiometry theory. Our findings revealed that, under N loading, microbial metabolism in both the surface (0–10 cm) and subsurface (10–20 cm) layers of the topsoil was limited by both C and P. Interestingly, with increasing P addition, microbial C limitation initially increased and then decreased at the surface but remained unchanged in the subsurface. Under conditions of C limitation, P enrichment did not alleviate microbial P limitation in either soil layer. Surprisingly, the microbial communities in both the surface and subsurface layers maintained plastic stoichiometric homeostasis despite aggravated C:P and N:P imbalances. Furthermore, P enrichment decreased microbial CUE in both soil layers, with the surface experiencing the most significant decline. Further analysis showed that the factors driving microbial nutrient limitation and CUE varied between soil layers under P enrichment, with enhanced microbial C limitation strongly inhibiting CUE. Our study indicates that increased C limitation due to P enrichment can reduce CUE and exacerbate stoichiometric imbalances. This could potentially lead to greater C loss in N‐enriched dryland soils.

Yulin Zhang, Yi Du, Zhaobin Mu et al.

Frontiers in Plant Science • 2025

Seasons often alter climate conditions and affect nutrient cycling by altering plant physiology and microbial dynamics. Plant growth and health depend on a symbiotic relationship with root microbes, however, the root-associated microbiota is key to plant evolution and ecosystem function. Seasonal changes in root-associated microbiome diversity and composition of desert plants are vital for understanding plant adaptation in desert ecosystems. We employed high-throughput sequencing to investigate the seasonal dynamics of root-associated microbial communities, including the root endosphere (RE), rhizosphere soil (RS), and bulk soil (BS), across three basins in Xinjiang, China: Turpan, Tarim, and Dzungaria. Proteobacteria dominated bacterial communities in different seasons, while Ascomycota prevailed in fungi. The spring and summer conditions favor greater microbial differentiation. The RE, RS, and BS bacterial communities in May (spring) showed a noticeable absence of highly connected nodes within and between modules. However, the opposite trend was observed in July (summer) and September (autumn). The community assembly of root-associated microbiome (bacteria and fungi) in different seasons primarily followed a random process. Random forest analysis found that seasonal variations in RE bacterial communities were primarily influenced by scattered radiation, while fungal communities were mainly affected by soil available potassium. Environmental factors affect the BS bacterial community more than the fungal community across different seasons. A structural equation model revealed temperature and precipitation’s direct effects on microbial communities, mediated by soil and root nutrient availability. Soil pH and EC predominantly affected root bacterial communities, not fungal communities. The fungal community within the RE was found to be directly influenced by seasonal shifts, whereas the RS fungal community composition was significantly impacted by changes in precipitation patterns driven by seasonal variation. The climate seems to be a crucial factor in influencing the dynamic of the root microbiome in desert plants, surpassing the influence of soil and root nutrient availability. This study underscores seasonal root-associated microbiome variations and their important roles in desert ecosystem functions.

C. Pardo-Esté, J. Castro-Severyn, F. Remonsellez et al.

Biogeosciences • 2025

Abstract. Lacustrine sediments are natural archives for the surrounding area's biogeochemical dynamics; in particular, the isolation and extreme conditions in which desert lakes are located make them ideal study models for studying perturbations in the ecosystem. We aimed to study the microbial community dynamics in Inka-Coya Lake, located in the Atacama Desert, where active geological activity and the local mining industry influence biological dynamics in this ecosystem, as suggested for macroinvertebrates and plankton communities in the lake. In this study, we aimed to characterize the microbial communities that inhabit deep lacustrine sediments and their interaction with the surrounding environment. The results show that the microbial community from lacustrine sediments contains over 70 % unclassified organisms, highlighting this ecosystem's microbial taxonomic novelty. Our results indicate that the microbial communities cluster in three distinct zones: a superficial community, an intermediate and mixed community, and a more specialized anaerobic community in the deeper sediments. The microbial composition is dominated by chemoheterotrophic bacteria strongly associated with methane metabolism. Additionally, there is statistical evidence of strong correlations between particular taxa such as Sulfurimonadaceae, Metanoregulaceae, and Ktedonobacteroceae with elements like Cu, As, Fe, Ni, and V, and magnetic properties of the surrounding environment, evidencing the strong correlation between the surrounding geochemistry and microbial life that could be disrupted by the continuous mining activity in the area. Further detailed studies of the metabolic repertoire of these communities are necessary to understand the complex dynamics between microbial life and geochemical composition in this fragile and extreme environment.

Patrick Jung, L. Lehnert, J. Bendix et al.

Frontiers in Astronomy and Space Sciences • 2022

The grit crust is a recently discovered, novel type of biocrust made of prokaryotic cyanobacteria, eukaryotic green algae, fungi, lichens and other microbes that grow around and within granitoid stone pebbles of about 6 mm diameter in the Coastal Range of the Atacama Desert, Chile. The microbial community is very well adapted towards the extreme conditions of the Atacama Desert, such as the highest irradiation of the planet, strong temperature amplitudes and steep wet-dry cycles. It also has several other striking features making this biocrust unique compared to biocrusts known from other arid biomes on Earth. It has already been shown that the grit crust mediates various bio-weathering activities in its natural habitat. These activities prime soil for higher organisms in a way that can be envisioned as a proxy for general processes shaping even extra-terrestrial landscapes. This mini-review highlights the potential of the grit crust as a model for astrobiology in terms of extra-terrestrial microbial colonization and biotechnological applications that support human colonization of planets.

R. Stancheva, Arun Sethuraman, Hossein Khadivar et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2023

Here we describe the metagenome composition, community functional annotation, and diversity of prokaryotic microbial species derived from calcareous stromatolite formations discovered in the dry stream bed of the open-canopy, ephemeral San Felipe Creek in the Anza Borrego Desert. In this environment, resident microbes must be able to adapt to the harsh conditions of extreme heat, high UV light, desiccation and fluctuating solubilization/precipitation and hydration/evaporation. Metagenomic analysis revealed a community capable of carrying out complete nitrogen fixation and assimilatory nitrate reduction, forming biofilms and quorum sensing, and potentially forming thick-walled akinetes as desiccation-resistant stages. Nitrogen cycling is likely to play a fundamental role in mediating both the structure of the stromatolite microbial community and the mineral precipitation/dissolution. The viruses present in the stromatolites, particularly Nodularia and Mycobacterium phages are also likely to impact community population dynamics and activity. Stromatolite community members possess different morphological and physiological strategies to cope with desiccation stress. Metagenomic signatures were found for scytonemin, carotenoids, synthesis of potential microsporine-like amino acids; genes involved in microalgal desiccation tolerance, including those encoding aquaporins, chaperones, antioxidants; and enzymes responsible for the synthesis of trehalose, sucrose, and polyamines. The stromatolite ecosystem provides a diverse array of microniches where different functional guilds can develop complex metabolite exchange with the substrate supporting their life in extreme conditions. Metagenome analyses revealed several genes that might enable a specialized and unique group of endolithic cyanobacteria including Chroococcidiopsis, Hyella, Myxosarcina, and Pleurocapsa to derive metals and important nutrients from rocks, being potentially destructive for the calcareous formations. Our study revealed environmental adaptations of freshwater microbial communities in desert stream stromatolites which may provide valuable insights into Precambrian paleoenvironments, which are little known.

Maria R. Monteiro, Alexis J Marshall, Charles K. Lee et al.

Polar Biology • 2023

Polar deserts contain unique and sensitive communities responsive to climate-associated habitat changes. However, unlike temperate desert ecosystems, characterizing and predicting the responses of polar ecosystems to environmental change remains a significant challenge due to logistical constraints. Here we aim to demonstrate the use of a custom-designed Polar Desert Environmental Chamber (PDEC) to perform off-continent experimental ecological research. We did so by characterizing the structure and composition of arid edaphic bacterial communities collected from the McMurdo Dry Valleys during a simulated wetting event. The results were discussed in light of previous field observations. Rapid structural and compositional changes were observed during wetting and re-drying treatments. Those were driven by changes in the relative abundance of coexisting taxa, which fluctuated asynchronously over time in response to the treatments. While selection was the main ecological factor influencing communities during dry conditions or the initial wetting, with prolonged exposure to wetness, neutral processes began to drive community assembly. Ultimately, these observations reflect different adaptative responses from microbial taxa to water stress, which can be argued as beneficial to increasing resilience in polar deserts. Our findings demonstrate that experiments conducted in PDEC provide valuable contextual data on community response to environmental change and can accelerate our ability to assess biological thresholds to change within polar desert ecosystems. We advocate that, with careful consideration of key emulated environmental attributes, laboratory-based Antarctic research can complement fieldwork to achieve a nuanced and evidence-based understanding of the ecology of Antarctica’s ice-free regions.

Don A. Cowan, S. Cary, J. DiRuggiero et al.

Microorganisms • 2023

Water availability is the dominant driver of microbial community structure and function in desert soils. However, these habitats typically only receive very infrequent large-scale water inputs (e.g., from precipitation and/or run-off). In light of recent studies, the paradigm that desert soil microorganisms are largely dormant under xeric conditions is questionable. Gene expression profiling of microbial communities in desert soils suggests that many microbial taxa retain some metabolic functionality, even under severely xeric conditions. It, therefore, follows that other, less obvious sources of water may sustain the microbial cellular and community functionality in desert soil niches. Such sources include a range of precipitation and condensation processes, including rainfall, snow, dew, fog, and nocturnal distillation, all of which may vary quantitatively depending on the location and geomorphological characteristics of the desert ecosystem. Other more obscure sources of bioavailable water may include groundwater-derived water vapour, hydrated minerals, and metabolic hydro-genesis. Here, we explore the possible sources of bioavailable water in the context of microbial survival and function in xeric desert soils. With global climate change projected to have profound effects on both hot and cold deserts, we also explore the potential impacts of climate-induced changes in water availability on soil microbiomes in these extreme environments.

F. Arens, A. Airo, C. Sager et al.

Biogeosciences • 2024

Abstract. Life in hyperarid regions has adapted to extreme water scarcity through mechanisms like salt deliquescence. While halite (NaCl) crusts have been intensively studied and identified as one of the last habitats under hyperarid conditions, other less common hygroscopic salt crusts remain unexplored. Here, we investigated newly discovered deliquescent soil surfaces in the Atacama Desert, containing substantial amounts of nitrates, to evaluate their habitability for microorganisms. We characterized the environment with respect to water availability and biogeochemistry. Microbial abundances and composition were determined by cell cultivation experiments, 16S rRNA gene sequencing, and membrane phospholipid fatty acid (PLFA) analysis, while microbial activity was assessed by analyzing adenosine triphosphate (ATP) and the molecular composition of organic matter. Our findings reveal that, while the studied hygroscopic salts provide temporary water, microbial abundances and activity are lower in the studied soil surfaces than in non-deliquescent soil surfaces. Intriguingly, the deliquescent crusts are enriched in geochemically degraded organic matter, indicated by the molecular composition. We conclude that high nitrate concentrations in the hyperarid soils suppress microbial activity but preserve eolian-derived biomolecules. These insights are important for assessing the habitability and searching for life in hyperarid environments on Earth and beyond.

Mansi Chauhan, Anita Pandey, Praveen Kumar et al.

Annals of Arid Zone • 2024

Cold deserts play a unique and crucial role in the environment. Glaciers in these regions store significant amounts of freshwater, essential for ecosystems, while permafrost sequesters large quantities of carbon, preventing the release of greenhouse gases. These areas host diverse species, contributing to global biodiversity and a variety of extremophile life forms. The microbial communities in cold deserts—comprising bacteria, cyanobacteria, archaebacteria, fungi, and lichens—have adapted to harsh conditions. They maintain ecological balance by forming symbiotic interactions with plants, enhancing soil fertility, and boosting crop yields. Additionally, several microorganisms are involved in bioremediation processes. Microorganisms found in cold desert environments also serve as valuable biosignatures for detecting life, significantly advancing the field of astrobiology. This review explores the microbial diversity of cold deserts through bibliometric analysis using VOSviewer software. The software identified 47 countries engaged in cold desert research, with the United States leading in the number of publications. A total of 2009 keywords were analyzed, with "bacteria (microorganisms)" being the most common. This review encompasses studies on the microbial diversity of cold deserts and their applications, highlighting crucial directions for future research

Wen-Hui Lian, O. A. Mohamad, Lei Dong et al.

Environmental Microbiome • 2023

Background The microbiome of the Sinai Desert farming system plays an important role in the adaptive strategy of growing crops in a harsh, poly-extreme, desert environment. However, the diversity and function of microbial communities under this unfavorable moisture and nutritional conditions have not yet been investigated. Based on culturomic and metagenomic methods, we analyzed the microbial diversity and function of a total of fourteen rhizosphere soil samples (collected from twelve plants in four farms of the Sinai desert), which may provide a valuable and meaningful guidance for the design of microbial inoculants. Results The results revealed a wide range of microbial taxa, including a high proportion of novel undescribed lineages. The composition of the rhizosphere microbial communities differed according to the sampling sites, despite similarities or differences in floristics. Whereas, the functional features of rhizosphere microbiomes were significantly similar in different sampling sites, although the microbial communities and the plant hosts themselves were different. Importantly, microorganisms involved in ecosystem functions are different between the sampling sites, for example nitrogen fixation was prevalent in all sample sites while microorganisms responsible for this process were different. Conclusion Here, we provide the first characterization of microbial communities and functions of rhizosphere soil from the Sinai desert farming systems and highlight its unexpectedly high diversity. This study provides evidence that the key microorganisms involved in ecosystem functions are different between sampling sites with different environment conditions, emphasizing the importance of the functional microbiomes of rhizosphere microbial communities. Furthermore, we suggest that microbial inoculants to be used in future agricultural production should select microorganisms that can be involved in plant-microorganism interactions and are already adapted to a similar environmental setting.

Patricio Arros, Daniel E. Palma, Matías Gálvez-Silva et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2024

The high-latitude regions of Antarctica remain among the most remote, extreme, and least explored areas on Earth. Despite the highly restrictive conditions, microbial life has been found in these environments, although with limited information on their genetic properties and functional capabilities. Moreover, the accelerated melting of the Antarctic permafrost, the increasing exposure of soils, and the growing human transit pose the question of whether these environments could be a source of microbes or genes that could emerge and cause global health problems. In this line, although a high bacterial diversity and autochthonous multidrug-resistant bacteria have been found in soils of the Antarctic Peninsula, we still lack information regarding the resistome of areas closer to the South Pole. Moreover, no previous studies have evaluated the pathogenic potential of microbes inhabiting Antarctic soils. In this work, we combined metagenomic and culture-dependent approaches to investigate the microbial diversity, resistome, virulome, and mobile genetic elements (MGEs) in soils from Union Glacier, a high-latitude cold desert in West Antarctica. Despite the low organic matter content, diverse bacterial lineages were found, predominating Actinomycetota and Pseudomonadota, with limited archaeal and fungal taxa. We recovered more than 80 species-level representative genomes (SRGs) of predominant bacterial taxa and the archaeon Nitrosocosmicus sp. Diverse putative resistance and virulence genes were predicted among the SRGs, metagenomic reads, and contigs. Furthermore, we characterized bacterial isolates resistant to up to 24 clinical antibiotics, mainly Pseudomonas, Arthrobacter, Plantibacter, and Flavobacterium. Moreover, some isolates produced putative virulence factors, including siderophores, pyocyanins, and exoenzymes with hemolytic, lecithinase, protease, and DNAse activity. This evidence uncovers a largely unexplored resistome and virulome hosted by deep Antarctica’s soil microbial communities and the presence of bacteria with pathogenic potential, highlighting the relevance of One Health approaches for environmental surveillance in the white continent. HIGHLIGHTS -Union Glacier soils host a microbial community dominated by bacteria, mainly from the phylum Actinomycetota. -Archaea from the Nitrosocosmicus genus (family Nitrosphaeraceae) were ubiquitously detected. -Although extreme and remote, these soils host multidrug-resistant and potentially pathogenic bacteria. Some were cultured and tested in vitro. -Metagenomes and species-level representative genomes revealed diverse putative resistance and virulence genes. -Part of the putative antimicrobial resistance genes and virulence factors could be associated with mobile elements in bacterial genomes.

K. Meiramkulova, Aliya Temirbekova, Gulnur Saspugayeva et al.

Preprints.org • 2021

The efficiency of microbial inactivation in water is highly dependent on the type of treatment technology used as well as the characteristics of the water to be treated. Wastewater from poultry slaughterhouses carries a significant number of microorganisms posing threats to humans and the environment in general. Therefore, the treatment of poultry slaughterhouse wastewater requires the use of appropriate purification systems with high removal efficiency for microbial agents. In this study, the performance of an integrated treatment plant with electrolysis, ultrafiltration, and ultraviolet radiation as the principal treatment units was investigated in terms of microbial inactivation from poultry slaughterhouse wastewater. In this case, total microbial number, total coliform bacteria, thermo-tolerant coliform bacteria, pathogenic flora, including salmonella coliphages, spores of sulfite-reducing clostridia, Pseudomonas aeruginosa, and Staphylococcus aureus and Enterococcus were studied. Approximately 63.95% to 99.83% of the microbes were removed by the electrochemical treatment unit as well as a 99.86% to 100% removal efficiency was achieved after the combined treatment. However, Pseudomonas aeruginosa was the only microbial agent detected in the final effluent after the combined treatment. The phenomenon suggests that an upgrade to the treatment plant may be required to achieve 100% removal assurance for Pseudomonas aeruginosa.

M. Abdallah, S. Greige, H. Beyenal et al.

Scientific Reports • 2022

Resource recovery and prevention of environmental pollution are key goals for sustainable development. It is widely reported that agro-industrial activities are responsible for the discharge of billions of liters of wastewater to the environment. Anaerobic digestion of these energy rich agro-industrial wastewaters can simultaneously mitigate environmental pollution and recover embedded energy as methane gas. In this study, an assessment of mono- and co-digestion of cheese whey wastewater (CWW) and poultry slaughterhouse wastewater (PSW) was conducted in 2.25-L lab-scale anaerobic digesters. Treatment combinations evaluated included CWW (R1), PSW (R2), 75:25 CWW:PSW (R3), 25:75 CWW:PSW (R4), and 50:50 CWW:PSW (R5). The digestion efficiencies of the mixed wastewaters were compared to the weighted efficiencies of the corresponding combined mono-digested samples. R4, with a mixture of 25% CWW and 75% PSW, achieved the greatest treatment efficiency. This corresponded with an average biodegradability of 84%, which was greater than for R1 and R2 at 68.5 and 71.9%, respectively. Similarly, R4 produced the highest average cumulative methane value compared to R1 and R2 at 1.22× and 1.39× for similar COD loading, respectively. The modified Gompertz model provided the best fit for the obtained methane production data, with lag time decreasing over progressive treatment cycles. PCoA and heatmap analysis of relative microbial abundances indicated a divergence of microbial communities based on feed type over the treatment cycles. Microbial community analysis showed that genus Petrimonas attained the highest relative abundance (RA) at up to 38.9% in the first two cycles, then subsequently decreased to near 0% for all reactors. Syntrophomonas was highly abundant in PSW reactors, reaching up to 36% RA. Acinetobacter was present mostly in CWW reactors with a RA reaching 56.5%. The methanogenic community was dominated by Methanothrix (84.3–99.9% of archaea). The presence of phosphate and Acinetobacter in CWW feed appeared to reduce the treatment efficiency of associated reactors. Despite Acinetobacter being strictly aerobic, previous and current results indicate its survival under anaerobic conditions, with the storage of phosphate likely playing a key role in its ability to scavenge acetate during the digestion process.

Sedolfo Jose Carrasquero Ferrer, Nayade Vanessa Domenech Polo, Altamira Rosa Díaz Montiel et al.

Revista de Gestão Social e Ambiental • 2024

Objective: To evaluate the acclimatization of microbial biomass in sequential reactors to optimize the treatment of wastewater from pig slaughterhouses.   Theoretical framework: The meat industry generates highly contaminated wastewater. Biological treatments, such as aerobic and anaerobic systems, are more efficient and sustainable than physicochemical ones.   Materials and methods: Industrial effluents were collected in a pig slaughterhouse and then characterized. The microbial biomass was collected from the same slaughterhouse and was subjected to an acclimatization process in a sequential batch reactor.   Results and discussion: The results showed that the wastewater from the pig slaughterhouse had high levels of BOD, COD and suspended solids, exceeding the limits established by local regulations. During the acclimatization process, the microbial biomass demonstrated a gradual improvement in its COD removal capacity, reaching efficiencies greater than 70%. The positive correlation observed between volumetric organic load and organic matter removal efficiency indicates that acclimated biomass has a greater capacity to treat effluents with high levels of organic load.   Research implications: Biomass acclimatization is essential to improve the efficiency of biological treatment in slaughterhouse effluents, reducing its environmental impact and the need for costly treatments.   Value/originality: This study proposes a more sustainable and efficient solution for the treatment of slaughterhouse wastewater, highlighting the importance of biomass acclimatization.

T. Delforno, G. V. Lacerda Júnior, M. F. Noronha et al.

MicrobiologyOpen • 2017

The 16S rRNA gene amplicon and whole‐genome shotgun metagenomic (WGSM) sequencing approaches were used to investigate wide‐spectrum profiles of microbial composition and metabolic diversity from a full‐scale UASB reactor applied to poultry slaughterhouse wastewater treatment. The data were generated by using MiSeq 2 × 250 bp and HiSeq 2 × 150 bp Illumina sequencing platforms for 16S amplicon and WGSM sequencing, respectively. Each approach revealed a distinct microbial community profile, with Pseudomonas and Psychrobacter as predominant genus for the WGSM dataset and Clostridium and Methanosaeta for the 16S rRNA gene amplicon dataset. The virome characterization revealed the presence of two viral families with Bacteria and Archaea as host, Myoviridae, and Siphoviridae. A wide functional diversity was found with predominance of genes involved in the metabolism of acetone, butanol, and ethanol synthesis; and one‐carbon metabolism (e.g., methanogenesis). Genes related to the acetotrophic methanogenesis pathways were more abundant than methylotrophic and hydrogenotrophic, corroborating the taxonomic results that showed the prevalence of the acetotrophic genus Methanosaeta. Moreover, the dataset indicated a variety of metabolic genes involved in sulfur, nitrogen, iron, and phosphorus cycles, with many genera able to act in all cycles. BLAST analysis against Antibiotic Resistance Genes Database (ARDB) revealed that microbial community contained 43 different types of antibiotic resistance genes, some of them were associated with growth chicken promotion (e.g., bacitracin, tetracycline, and polymyxin).

M. Ng, S. Dalhatou, Jessica M. Wilson et al.

Processes • 2022

Commercialization in the meat-processing industry has emerged as one of the major agrobusiness challenges due to the large volume of wastewater produced during slaughtering and cleaning of slaughtering facilities. Slaughterhouse wastewater (SWW) contains proteins, fats, high organic contents, microbes, and other emerging pollutants (pharmaceutical and veterinary residues). It is important to first characterize the wastewater so that adequate treatment techniques can be employed so that discharge of this wastewater does not negatively impact the environment. Conventional characterization bulk parameters of slaughterhouse wastewater include pH, color, turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and coliform counts. Characterization studies conducted have revealed the effects of the pollutants on microbial activity of SWW through identification of toxicity of antibiotic-resistant strains of bacteria. Due to the high-strength characteristics and complex recalcitrant pollutants, treatment techniques through combined processes such as anaerobic digestion coupled with advanced oxidation process were found to be more effective than stand-alone methods. Hence, there is need to explore and evaluate innovative treatments and techniques to provide a comprehensive summary of processes that can reduce the toxicity of slaughterhouse wastewater to the environment. This work presents a review of recent studies on the characterization of SWW, innovative treatments and technologies, and critical assessment for future research.

Osayomwanbo Osarenotor, Isoken Tito Aighewi, Helen Michelle Korkor Essandoh et al.

Studia Universitatis Babeş-Bolyai Biologia • 2024

Mycofiltration is a recent cost-effective biotechnology that is still under development for wastewater treatment. The use of mycelium-colonised substrate for wastewater treatment in a batch system with delayed residence time and the effect of sawdust particles has not previously been considered. Slaughterhouse wastewater is discharged untreated in many developing countries majorly due to the high cost of existing conventional treatment systems. The effect of sawdust detention time and particle size on the removal efficiency of faecal bacteria from slaughterhouse wastewater by Pleurotus ostreatus mycelium was assessed in the lab using mycelium colonized with sawdust of particle sizes (0.6, 1.18, 2.36 mm and unsorted particle sizes) and under varying detention times (0, 12, 24, 36, 48, 60 and 72 hours) using batch treatment procedure. Hydrogen peroxide produced during mycelium colonisation of the sawdust was also evaluated. Oxidation-reduction potential (ORP) was measured during this study to determine the oxidative capacity in each treatment reactor. The removal efficiency of Escherichia coli ranged from -7.9 – 77.2 % and was the highest for mycofilter with 2.36 mm sawdust particle size at 72 hours detention time (0.7 log removal). Salmonella spp. removal efficiency ranged from 0.66 – 71 % with the highest efficiency recorded in the system with 1.16 mm also at 72 hours (0.4 log removal). Mean hydrogen peroxide concentration ranged from 0.53±0.12 (unsorted inoculated) to 25.18±1.77 mg/l (1.18 mm, 72 hours). ORP values ranged from 5.0±2.2 mV (raw wastewater, 24 hours) to 232±55 mV (unsorted inoculated, 72 hours). The result of this study showed that substrate particle size and detention time have roles to play in the efficiency of mycofilters using batch treatment. The concentration of hydrogen peroxide was also influenced significantly by sawdust particle size. Therefore, there is a need to further study this system in a bid to optimize its ability to remove faecal bacteria from wastewater.

Marcelinus Christwardana, Adrianus Kristyo Prabowo, Agnes Priska Tiarasukma et al.

International Journal of Renewable Energy Development • 2016

Microbial fuel Cell (MFC) has gained a lot of attention in recent years due to its capability in simultaneously reducing organic component and generating electricity. Here multicultural rumen microbes (RM) were used to reduce organic component of slaughterhouse wastewater in a self-fabricated MFC. The objectives of this study were to determine the MFC configuration and to find out its maximum capability in organic degradation and electricity generation. The experiments were conducted by employing, different types of electrode materials, electrode size, and substrate-RM ratio. Configuration of MFC with graphite-copper electrode 31.4 cm2 in size, and substrate-RM ratio 1:10 shows the best result with current density of 318 mA m-2, potential 2.4 V, and achieve maximum power density up to 700 mW m-2. In addition, self-fabricated MFC also shows its ability in reducing organic component by measuring the chemical oxygen demand (COD) up to 67.9% followed by increasing pH from 5.9 to 7.5. MFC operating at ambient condition (29oC and pH 7.5), is emphasized as green-technology for slaughterhouse wastewater treatment. Article History: Received March 26, 2016; Received in revised form June 20, 2016; Accepted June 25, 2016; Available onlineHow to Cite This Article: Prabowo, A.K., Tiarasukma, A.P., Christwardana, M. and Ariyanti, D. (2016) Microbial Fuel Cells for Simultaneous Electricity Generation and Organic Degradation from Slaughterhouse Wastewater. Int. Journal of Renewable Energy Development, 5(2), 107-112.http://dx.doi.org/10.14710/ijred.5.2.107-112

K. Chandrasekhar, A. Naresh Kumar, Tirath Raj et al.

Systems Microbiology and Biomanufacturing • 2021

Abstract Bioelectrochemical systems (BESs) are a new and emerging technology in the field of fermentation technology. Electrical energy was provided externally to the microbial electrolysis cells (MECs) to generate hydrogen or value-added chemicals, including caustic, formic acid, acetic acid, and peroxide. Also, BES was designed to recover nutrients, metals or remove recalcitrant compounds. The variety of naturally existing microorganisms and enzymes act as a biocatalyst to induce potential differences amid the electrodes. BESs can be performed with non-catalyzed electrodes (both anode and cathode) under favorable circumstances, unlike conventional fuel cells. In recent years, value-added chemical producing microbial electrosynthesis (MES) technology has intensely broadened the prospect for BES. An additional strategy includes the introduction of innovative technologies that help with the manufacturing of alternative materials for electrode preparation, ion-exchange membranes, and pioneering designs. Because of this, BES is emerging as a promising technology. This article deliberates recent signs of progress in BESs so far, focusing on their diverse applications beyond electricity generation and resulting performance.

Fu Yuting, Li Changbo, Zhao Guozheng et al.

E3S Web of Conferences • 2021

Shale oil refinery wastewater was a kind of industrial wastewater with many types of organic matter and complex water quality. It contains a large amount of pollutants such as phenols, ammonia and oil, which is extremely harmful to the environment. Due to the increasingly stringent national discharge standards, it was difficult to treat wastewater up to standard with only one method, and multiple methods are needed to jointly treat wastewater. In this paper, the process of shale oil refinery wastewater treatment system was modified, and the “SDN+Advanced Oxidation+MBR” process was proposed to treat wastewater.

Emmanuel K. Tetteh, Elorm Obotey Ezugbe, Sudesh Rathilal et al.

Water • 2020

Advanced oxidation processes (AOPs) have many prospects in water and wastewater treatment. In recent years, AOPs are gaining attention as having potentials for the removal of different ranges of contaminants from industrial wastewater towards water reclamation. In this study, the treatability efficiencies of two photo-catalysts (TiO2 and zeolite) were compared on the basis of the removal of chemical oxygen demand (COD) and SO42− from oil refinery wastewater (ORW) using photo-catalytic system. The effects of three operating parameters: catalyst dosage (0.5–1.5 g/L), reaction time (15–45 min), mixing rate (30–90 rpm) and their interactive effects on the removal of the aforementioned contaminants were studied using the Box–Behnken design (BBD) of response surface methodology (RSM). Statistical models were developed and used to optimize the operating conditions. An 18 W UV light was incident on the system to excite the catalysts to trigger a reaction that led to the degradation and subsequent removal of contaminants. The results obtained showed that for almost the same desirability (92% for zeolite and 91% for TiO2), TiO2 exhibited more efficiency in terms of mixing rate and reaction time requirements. At the 95% confidence level, the model’s predicted results were in good agreement with experimental data obtained.

Santisak Kitjanukit, Kyohei Takamatsu, Naoko Okibe

Water • 2019

Natural attenuation of Mn(II) was observed inside the metal refinery wastewater pipeline, accompanying dark brown-colored mineralization (mostly MnIVO2 with some MnIII2O3 and Fe2O3) on the inner pipe surface. The Mn-deposit hosted the bacterial community comprised of Hyphomicrobium sp. (22.1%), Magnetospirillum sp. (3.2%), Geobacter sp. (0.3%), Bacillus sp. (0.18%), Pseudomonas sp. (0.03%), and non-metal-metabolizing bacteria (74.2%). Culture enrichment of the Mn-deposit led to the isolation of a new heterotrophic Mn(II)-oxidizer Pseudomonas sp. SK3, with its closest relative Ps. resinovorans (with 98.4% 16S rRNA gene sequence identity), which was previously unknown as an Mn(II)-oxidizer. Oxidation of up to 100 mg/L Mn(II) was readily initiated and completed by isolate SK3, even in the presence of high contents of MgSO4 (a typical solute in metal refinery wastewaters). Additional Cu(II) facilitated Mn(II) oxidation by isolate SK3 (implying the involvement of multicopper oxidase enzyme), allowing a 2-fold greater Mn removal rate, compared to the well-studied Mn(II)-oxidizer Ps. putida MnB1. Poorly crystalline biogenic birnessite was formed by isolate SK3 via one-electron transfer oxidation, gradually raising the Mn AOS (average oxidation state) to 3.80 in 72 h. Together with its efficient in vitro Mn(II) oxidation behavior, a high Mn AOS level of 3.75 was observed with the pipeline Mn-deposit sample collected in situ. The overall results, including the microbial community structure analysis of the pipeline sample, suggest that the natural Mn(II) attenuation phenomenon was characterized by robust in situ activity of Mn(II) oxidizers (including strain SK3) for continuous generation of Mn(IV). This likely synergistically facilitated chemical Mn(II)/Mn(IV) synproportionation for effective Mn removal in the complex ecosystem established in this artificial pipeline structure. The potential utility of isolate SK3 is illustrated for further industrial application in metal refinery wastewater treatment processes.

Ivan Radelyuk, Kamshat Tussupova, Kulshat Zhapargazinova et al.

Sustainability • 2019

The present article is an assessment of wastewater treatment processes in the oil refinery sector in Kazakhstan by comparing relevant experience of developed and developing countries. The legislation in this sphere, the treatment methods, the discharge process and the effect on the environment were evaluated following international and national regulations. In our study, the wastewater systems in three factories in Kazakhstan were assessed. Results show that, even though the environmental regulation in Kazakhstan promotes the polluter pays principle and follows the World Health Organization (WHO) recommendations, the oil refinery plants in Kazakhstan still contain exceeding concentrations of pollutants in their effluents. One issue is that the local legislation allows disposal of wastewater to natural or artificial ponds as long as the concentrations of pollutants in effluents are less than the already existing concentrations in the pond. Consequently, the factories can use ponds with an initially high concentration of contaminants. The high initial concentration of pollutants in the pond water is due to wastewater discharged before the implementation of current environmental regulations. This issue in the current legislation leads to the situation where there is no incentive for efficient wastewater treatment. The national law also lacks regulations regarding which methodology should be used to assess the pollutants in the wastewater. Thus, the control by national environmental office for each enterprise is negotiated separately between the factory and the governmental body. This gives the factory a strong position to define the parameters assessing the effluents. This has led to none of the factories measuring, e.g., heavy metals in discharged wastewater. Total petroleum hydrocarbons (TPH) concentration in wastewater is often exceeded at each factory and there is no analysis done for different hydrocarbon fraction. To overcome the issues described in the present study, we strongly recommended a unified and transparent methodology for the country’s oil refinery industry to assess important pollutants in discharged wastewater.