Ramya Veerubhotla, Aditya Bandopadhyay, Suman Chakraborty

bioRxiv (Cold Spring Harbor Laboratory) • 2022

Abstract The recent COVID-19 crisis necessitated the universal use of Personal Protection Equipment (PPE) kits, generating tons of plastic wastes that inevitably lead to environmental damage. Circumventing the challenges stemming from such undesirable non-degradability on disposal, here we present an eco-friendly, robust, yet inexpensive and equipment-free method of growing biodegradable PPE fabrics by the fermentation of locally-sourced organic feed stocks in a rural livelihood. Using a pre-acclimatized symbiotic culture, we report the production of a high yield (up to 3.2 g fabric/g substrate) of bacterial cellulose, a biopolymer matrix, obtained by bacterial weaving. This membrane has an intricate, self-assembled, nano-porous 3D architecture formed by randomly oriented cellulose fibres. Scanning electron microscopy reveals that the pore size of the membrane turns out to be in the tune of 140 nanometers on the average, indicating that it can filter out viruses effectively. In-vitro results demonstrate assured breathability through the membrane for a filter thickness of approximately 5 microns. When subjected to soil degradation, the fabrics are seen to disintegrate rapidly and fully decompose within 15 days. With a favourable cost proposition of less than 1 US$ per meter square of the developed fabric unit, our approach stands out in providing a unique sustainable, and production-ready alternative to synthetic PPE fabrics, solving community healthcare and environmental crisis, and opening up new avenues sustainable under-served livelihood at the same time. Graphical abstract

E. R. Blakley

Canadian Journal of Microbiology • 1972

An unidentified bacterium degrades p-hydroxyphenylacetic acid by a pathway which involves homogentisic acid as an intermediate. Extracts of cells grown on p-hydroxyphenylacetic acid contain an enzyme that converts p-hydroxyphenylacetic acid to homogentisic acid. The enzyme has been partially purified by ammonium sulfate fractionation and some of its properties examined. The complete oxidation of 1 mole of p-hydroxyphenylacetic acid requires 1 mole of either NADH or NADPH, and 1 mole of oxygen, and results in the production of 1 mole of homogentisic acid. The enzyme preparation has a high specificity for p-hydroxyphenylacetic acid, but has about 25% activity with p-hydroxyphenylpyruvic acid.

Irina Zanina, Eugenia Kostromina, Natalia Stuzhenko et al.

E3S Web of Conferences • 2020

The article presents the results of an analysis of modern research in the field of organic waste processing. To solve the problem, anaerobic bioconversion method was chosen. The data of experimental laboratory experiments on the selection of a consortium of microorganisms’ methanizing waste from poultry farms with maximum efficiency are presented.

Manuel Layer, Antoine Brison, Mercedes Garcia Villodres et al.

Environmental Science: Water Research & Technology • 2022

Particulate organic substrate (X B ) represents the major fraction of organic substrate in low-strength municipal wastewater (MWW) but its hydrolysis, conversion and utilisation in aerobic granular sludge (AGS) are not well understood.

H. A. Mousa, M. G. Abaid

Eastern Mediterranean Health Journal • 2000

From 1983 to 1989, 110 cases of haematogenous osteomyelitis were studied retrospectively. The most commonly affected were children under 1 year. No adult cases were reported. Staphylococcus aureus was isolated from 72.7% of cases. During 1992-1997, 80 cases were studied prospectively. The most commonly affected were children aged 9 years. This group included 19 adults. S. aureus was isolated from 43.7% of the cases. There was a clear difference in the incidence of S. aureus and age presentation in the cases before and after the Gulf conflict. Working children and malnutrition might have caused changes in the infecting organisms and age presentation in recent years

Van Bon Nguyen, San-Lang Wang

Marine Drugs • 2017

Six kinds of chitinous materials have been used as sole carbon/nitrogen (C/N) sources for producing α-glucosidase inhibitors (aGI) by Paenibacillus sp. TKU042. The aGI productivity was found to be highest in the culture supernatants using demineralized crab shell powder (deCSP) and demineralized shrimp shell powder (deSSP) as the C/N source. The half maximal inhibitory concentration (IC50) and maximum aGI activity of fermented deCSP (38 µg/mL, 98%), deSSP (108 µg/mL, 89%), squid pen powder (SPP) (422 µg/mL, 98%), and shrimp head powder (SHP) (455 µg/mL, 92%) were compared with those of fermented nutrient broth (FNB) (81 µg/mL, 93%) and acarbose (1095 µg/mL, 74%), a commercial antidiabetic drug. The result of the protein/chitin ratio on aGI production showed that the optimal ratio was 0.2/1. Fermented deCSP showed lower IC50 and higher maximum inhibitory activity than those of acarbose against rat intestinal α-glucosidase.

Robert J. Theriault, Thomas H. Longfield

Applied Microbiology • 1967

Approximately 700 cultures of various types were examined for their ability to hydroxylate acetanilide. The major product formed by unidentified Streptomyces species RJTS-539 was identified as 4′-hydroxyacetanilide ( N -acetyl- p -aminophenol). This culture gave a peak yield of 405 mg per liter from 1,000 mg of acetanilide per liter. Considerably lower yields of 4′-hydroxyacetanilide were isolated from S. cinnamoneus NRRLB-1285. The major conversion product of acetanilide formed by Amanita muscaria F-6 was identified as 2′-hydroxyacetanilide, with a peak yield of 433 mg per liter from 1,000 mg per liter of substrate. A small amount of 4′-hydroxyacetanilide was also formed. Six other Streptomyces cultures formed small amounts of one or two products identical or similar to 2′-hydroxyacetanilide or 4′-hydroxyacetanilide as determined by thin-layer chromatography and ultraviolet spectra.

Tse-Yi Wang, Chien-Hao Su, Huai-Kuang Tsai

Bioinformatics • 2011

Abstract Motivation: Metagenomics involves sampling and studying the genetic materials in microbial communities. Several statistical methods have been proposed for comparative analysis of microbial community compositions. Most of the methods are based on the estimated abundances of taxonomic units or functional groups from metagenomic samples. However, such estimated abundances might deviate from the true abundances in habitats due to sampling biases and other systematic artifacts in metagenomic data processing. Results: We developed the MetaRank scheme to convert abundances into ranks. MetaRank employs a series of statistical hypothesis tests to compare abundances within a microbial community and determine their ranks. We applied MetaRank to synthetic samples and real metagenomes. The results confirm that MetaRank can reduce the effects of sampling biases and clarify the characteristics of metagenomes in comparative studies of microbial communities. Therefore, MetaRank provides a useful rank-based approach to analyzing microbiomes. Contact: hktsai@iis.sinica.edu.tw Supplementary Information: Supplementary data are available at Bioinformatics online.

S. Patrabansh, M. Madan

Acta Biotechnologica • 1995

Abstract A number of agricultural residues such as Saccharum munja Roxb. (Sarkanda), Oryza sativa L. (Paddy straw, as the control), Vinna unguiculata (L.) Walp (Cowpeas), Abelmoschus esculentum (L.) Moench (Lady's finger), Zea mays L. (Maize) and Cyamopsis tetragonoloba (L.) Taub. (Guar) were used for the cultivation of Pleurotus sajor‐caju (Fr.) Singer. The biological efficiency of the fruit bodies of Pleurotus sajor‐caju from the above mentioned substrates were found to be 13.47, 11.20, 8.37, 8.31, 6.87, and 6.08 percent, respectively. S. munja and paddy straw were found to be the best substrates for the growth of P. sajor‐caju followed by Z. mays, V. unguiculata, A. esculentum , and C. tetragonoloba .

Filip Boratyński, Ewa Szczepańska, Jakub Pannek et al.

Catalysts • 2015

It has been shown that whole cells of different strains of yeast catalyze stereoselective oxidation of meso diols to the corresponding chiral lactones. Among screening-scale experiments, Candida pelliculosa ZP22 was selected as the most effective biocatalyst for the oxidation of monocyclic diols 3a–b with respect to the ratio of high conversion to stereoselectivity. This strain was used in the preparative oxidation, affording enantiomerically-enriched isomers of lactones: (+)-(3aR,7aS)-cis-hexahydro-1(3H) -isobenzofuranone (2a) and (+)-(3aS,4,7,7aR)-cis-tetrahydro-1(3H)-isobenzofuranone (2b). Scaling up the culture growth, as well as biotransformation conditions has been successfully accomplished. Among more bulky substrates, bicyclic diol 3d was totally converted into enantiomerically-pure exo-bridged (+)-(3aR,4S,7R,7aS)-cis-tetrahydro-4,7-methanoisobenzofuran -1(3H)-one (2d) by Yarrovia lipolytica AR71. Microbial oxidation of diol 3f by Candida sake AM908 and Rhodotorula rubra AM4 afforded optically-pure cis-3-butylhexahydro-1(3H) -isobenzofuranone (2f), however with low conversion.

Ch. Tamm

Angewandte Chemie International Edition in English • 1962

Abstract Micro‐organisms form enzymes that catalyze many reactions which are difficult to carry out in the laboratory or which involve many steps. Enzymes even react with substances which are normally foreign to them. The frequently high stereospecificity of microbiological reactions is of particular significance. The most important types of reactions are: hydroxylations, dehydrogenations (oxidations), and hydrogenations (reductions), cleavage of ester and C‐C bonds, and transglycosidations. The variety of the compounds converted is extremely great.

Paola Iovieno, Riccardo Scotti, Massimo Zaccardelli

Agriculture • 2021

In the National park of Cilento, Vallo di Diano and Alburni (South Italy), a portion of a chestnut forest was converted in 2012 into an agricultural system in order to crop a local variety of bean. We investigated the effect over time of the conversion on the functional diversity of the soil microbial community by two different approaches: the catabolic response profile, based on the short time CO2 evolution induced by 25 simple organic substrates and the Biolog community level physiological profile (CLPP), based on the growth of microorganisms on 31 different substrates. The soils were sampled at 13, 17, 29, 41 and 49 months after the soil use change. The results showed that the soil use change did not produce evident modifications of the substrate utilization patterns, but rather a general decrease in the activity in the agricultural soils, as a consequence of the reduction in organic matter content. The results also showed seasonal effects on the substrate utilization profiles and on the calculated functional diversity indexes. The two approaches appeared to be complementary: Degens catabolic response profile was more able to discriminate between the two systems, whereas the Biolog was more able to highlight the variability among samplings.

Galal T. Maatooq

Zeitschrift für Naturforschung C • 2002

The biotransformation of partheniol by the fungus Calonectria decora ATCC 14767, produced six metabolites. These metabolites are; aromadendr-1(10)-en-8α -ol; 5(9),6-tricyclohumul- 1(10)-en-8α-ol; 4,15-didehydro-6-bicyclohumulan-8α,10α-diol; 5(9),6-tricyclohumulan- 4α,8α-diol; maalian-1α,8α-diol and 14-epi-1(4)-epoxymaalian-8α-ol. The identities of these metabolites were established by different spectroscopic measurements.

Y.-S. Lin, V. B. Heuer, T. G. Ferdelman et al.

• 2010

Abstract. In anoxic environments, volatile methylated sulfides including methanethiol (MT) and dimethyl sulfide (DMS) link the pools of inorganic and organic carbon with the sulfur cycle. However, direct formation of methylated sulfides from reduction of dissolved inorganic carbon has previously not been demonstrated. During examination of the hydrogenotrophic microbial activity at different temperatures in the anoxic sediment from Lake Plußsee, DMS formation was detected at 55 °C and was enhanced when bicarbonate was supplemented. Addition of both bicarbonate and H2 resulted in the strongest stimulation of DMS production, and MT levels declined slightly. Addition of methyl-group donors such as methanol and syringic acid or methyl-group acceptors such as hydrogen sulfide did not enhance further accumulation of DMS and MT. The addition of 2-bromoethanesulfonate inhibited DMS formation and caused a slight MT accumulation. MT and DMS had average δ13C values of −55‰ and −62‰, respectively. Labeling with NaH13CO3 showed that incorporation of bicarbonate into DMS occurred through methylation of MT. H235S labeling demonstrated a microbially-mediated, but slow, process of hydrogen sulfide methylation that accounted for <10% of the accumulation rates of DMS. Our data suggest: (1) methanogens are involved in DMS formation from bicarbonate, and (2) the major source of the 13C-depleted MT is neither bicarbonate nor methoxylated aromatic compounds. Other possibilities for isotopically light MT, such as demethylation of 13C-depleted DMS or other organic precursors such as methionine, are discussed. This DMS-forming pathway may be relevant for anoxic environments, such as hydrothermally influenced sediments and fluids and sulfate-methane transition zones in marine sediments.

Cheng Li, Keaton Lesnik, Hong Liu

Energies • 2013

Biodiesel has gained a significant amount of attention over the past decade as an environmentally friendly fuel that is capable of being utilized by a conventional diesel engine. However, the biodiesel production process generates glycerol-containing waste streams which have become a disposal issue for biodiesel plants and generated a surplus of glycerol. A value-added opportunity is needed in order to compensate for disposal-associated costs. Microbial conversions from glycerol to valuable chemicals performed by various bacteria, yeast, fungi, and microalgae are discussed in this review paper, as well as the possibility of extending these conversions to microbial electrochemical technologies.

Yizhen Wang

MATEC Web of Conferences • 2025

This paper highlights developments in microbial electrosynthesis (MES), metabolic engineering, and photosynthetic biohybrid systems (PBSs) for biofuel production, which offer a sustainable solution to lessen dependency on fossil fuels and the emission of greenhouse gases. MES uses electroactive microbes to convert CO2 into ethanol, methane, and other fuels using renewable electricity while integrating wastewater treatment; metabolic engineering improves CO2 fixation by redesigning microbial pathways; and PBSs combine inorganic semiconductors with biological catalysts to improve solar energy conversion. Methane synthesis through hydrogenotrophic methanogenesis and ethanol production via acetyl-CoA pathways are examples of targeted biofuel synthesis. However, the overall energy yields remain suboptimal for large-scale deployment. Slow reaction rates, expensive hydrogen, and fluctuating CO2 fixation efficiencies in microalgae systems are among the difficulties that are impacted by reactor design and operating factors. Process optimization and strain engineering innovations hold promise for scalability. However, further research is required due to the infrastructural requirements and economic viability of CO2 capture and hydrogen delivery. Realizing the full potential of microbial CO2 conversion technologies in reaching carbon neutrality will require addressing these technological and financial obstacles through interdisciplinary methods.

N. Yemashova, S. Kalyuzhnyi

Water Science and Technology • 2006

Four selected azo dyes (acid orange 6, acid orange 7, methyl orange and methyl red) were completely decolourised in the presence of anaerobic granular sludge, while only methyl red was degraded in aerobic conditions using a conventional activated sludge. Additional experiments with culture broth devoid of cells showed that anaerobic decolourisation of azo dyes was performed by extracellular reducing agents produced by anaerobic bacteria. This was further confirmed by abiotic experiments with sulphide and NADH. The presence of redox mediators such as riboflavin led to dramatic acceleration of the anaerobic biodecolourisation process. The azo dye reduction products were found to be sulphanilic acid and 4-aminoresorcinol for acid orange 6; sulphanilic acid and 1-amino-2-naphthol for acid orange 7; N,N-dimethyl-1,4-phenylenediamine and sulphanilic acid for methyl orange; and N,N-dimethyl-1,4-phenylenediamine and anthranilic acid for methyl red. Anaerobic toxicity assays showed that the azo dyes were more toxic than their breakdown products (aromatic amines), except 1-amino-2-naphthol. In the presence of activated sludge, only anthranilic acid was completely mineralised while sulphanilic acid was persistent. 4-aminoresorcinol, 1-amino-2-naphthol and N,N-dimethyl-1,4-phenylenediamine underwent autooxidation in aerobic conditions yielding coloured polymeric products. On the contrary, in the presence of granular methanogenic sludge, 4-aminoresorcinol, 1-amino-2-naphthol and anthranilic acid were quantitatively methanised, sulphanilic acid was partially (70%) mineralised while N,N-dimethyl-1,4-phenylenediamine was only demethylated producing 1,4-phenylenediamine as an end product.

Pingnan Zhao, Shen Wang, Dong Liu et al.

Research Square • 2021

Abstract In northeastern China, successive years of cultivation have led to a decline in soil quality, a process that is exacerbated by the over-application of chemical fertilizers to ensure staple food production. The large amount of straw produced by cultivation is difficult to effectively use in recent years. There has been an increasing amount of research on the transforming straw into biomass char, but it has often focused on the effects of biomass char addition on soil physicochemical properties, without further exploring the mechanisms of this process and its effects on soil microorganisms. Microorganisms are an important part of the soil system and the process of how biomass char addition affects microorganisms through its effect on soil physicochemical properties should not be overlooked. In this study， the effect of biochar application at different preparation temperatures (300°C, 400°C and 500°C) and addition contents (0.1% and 1%) on ammonia, nitrate and total nitrogen in soil leachates were investigated. The effect of microbial sequencing on the dynamics of carbon and nitrogen was also investigated to reveal the mechanisms contributing to the changes in nitrogen forms. The results showed that biochar had a better adsorption ability on ammonia nitrogen, and biochar promoted the conversion of ammonia nitrogen to nitrate nitrogen by nitrifying bacteria. The addition of 1% biochar (prepared at 500°C) increased nitrate-nitrogen leaching by 86.52% compared to the control treatment. The sequencing of microorganisms also revealed that biochar changed the structure and abundance of the soil microbial community, especially increasing the relative abundance of the Helicobacter nitrification phylum by 2.02%. These results indicates that biochar facilitated the adsorption of ammonium nitrogen and the conversion of nitrate nitrogen, and solving the problem of low nitrogen fertilizer utilization while promoting the formation of beneficial bacteria in the soil.

Stanislav Rudnyckyj, Tanmay Chaturvedi, Mette Hedegaard Thomsen

Biomass Conversion and Biorefinery • 2025

Abstract The study investigated the potential of the organic fraction of municipal solid waste (OFMSW) for microbial biomass production. The compositional analysis of OFMSW showed richness in sugars, proteins, lipids, organic acids, and ethanol, suggesting promising cheap cultivation feedstock if inhibitory compounds are sustainably detoxified. The enzymatic hydrolysis with Cellic® CTec3 and AMG® 300 L BrewQ (Novozymes A/S) demonstrated excellent saccharification of sugar polymer, reaching 92% glucan hydrolysis and 70% xylan hydrolysis. However, higher enzymatic dosages led to a rise in the total organic acids content, potentially causing increased microbial inhibition. Full hydrolysate and hydrolysate after solids removal were cultivated with seven robust microbial strains. Cultivation on hydrolysate with solids showed consumption of sugars and organic acids solely by commercial backer yeast Saccharomyces cerevisiae . Removal of solids from hydrolysate resulted in increased performance of tested strains, showing consumption of measured organic acids and ethanol by S. cerevisiae , Yarrowia lipolytica DSM 8218, and Cutaneotrichosporon oleaginosus ATCC 20509. Remarkably, the investigation of biomass production revealed superior cell mass formation and detoxification by S. cerevisiae , resulting in 18.9 g of biomass/L hydrolysate with 50% of crude protein (w/w) in shake flasks and 13.2 g/L of hydrolase with 46% of crude protein (w/w) in a 5-L bioreactor. Furthermore, bioreactor cultivation confirmed organic acids and ethanol conversion into biomass, highlighting S. cerevisiae ’s suitability for utilizing OFMSW for microbial biomass production. These findings contribute to advancements in biowaste-to-fodder conversion, promoting the development of a more sustainable circular economy. Graphical abstract

Alexandru Dumitrache

• 2021

Recent findings support the concept that Clostridium thermocellum is a cellulose-utilizing specialist having growth benefits with increasing substrate chain length. We developed a continuous-flow system for in-situ detection of cellulose colonization and qualitatively assayed metabolic activities and behaviour of cellulolytic cultures. This study demonstrates the existence of strongly adherent celluloytic cells arranged in monolayers with invariably end-on attached spores. The substrate-cell distance was recorded to be lower than 0.44 pm and a typical EPS matrix was absent. Measurements on carbon dioxide released in continuous-flow cultures was successfully employed to monitor biofilm activity and total carbohydrate assays do not reveal loss of cellulolysis end-products in the effluent. These findings demonstrate the bacteria have optimized access to the cellulosic substrates and suggest that they have an ability to sequester products of substrate hydrolysis which confers benefits over non-adherent cellulolytic or non-cellulolytic organisms.

Tong Zhang, Yufei Liu, xin Sui et al.

Research Square (Research Square) • 2020

Abstract Background : To study the impact of land-use change on soil microbial community structure and diversity in Northeast China, three typical land-use types (plough, grassland, and forest), grassland change to forest land and grassland change to plough, in the Qiqihar region of Heilongjiang Province were taken as research objects. Methods : MiSeq high-throughput sequencing technology based on bacterial 16S rRNA and fungal ITS rRNA was used to study the above community structure of soil bacteria and fungi and to explore the relationship between soil bacteria and soil environmental factors. Results : The results showed that the dominant bacterial phyla changed from Actinobacteria to Acidobacteria , the dominant fungal phyla changed from Ascomycetes to Basidiomycetes , and the ECM functional group increased significantly after the grassland was completely changed to forest land. After the grassland was changed to plough, the dominant phyla changed from Actinomycetes to Proteobacteria . The functional groups of pathogens and parasites increased significantly. There was no significant difference in the diversity of soil bacterial communities, and the diversity of fungal communities increased significantly. CCA showed that pH, MC, NO 3 - -N, TP and AP of soil were important factors affecting the composition of soil microbial communities, and changes in land-use patterns changed the physical and chemical properties of soils, thereby affecting the structure and diversity of microbial communities. Conclusions : Our research results clarify the impact of changes in land use on the characteristics of soil microbial communities and provide basic data on the healthy use of land.

Anastasiia Afanasenko, Tao Yan, Katalin Barta

Communications Chemistry • 2019

Abstract β-amino acid esters are important scaffolds in medicinal chemistry and valuable building blocks for materials synthesis. Surprisingly, the waste-free construction of such moieties from readily available or renewable starting materials has not yet been addressed. Here we report on a robust and versatile method for obtaining β-amino acid esters by direct amination of β-hydroxyl acid esters via the borrowing hydrogen methodology using a cooperative catalytic system that comprises a homogeneous ruthenium catalyst and an appropriate Brønsted acid additive. This method allows for the direct amination of esters of 3-hydroxypropionic acid, a top value-added bio-based platform chemical, opening a simple route to access β-amino acid esters from a range of renewable polyols including sugars and glycerol.

Yue-Ming Wang, Fabio Lorenzini, Martin Rebros et al.

Green Chemistry • 2016

The hydrogen transfer initiated dehydration of 1,3-propanadiol to propionaldehyde, catalysed by a highly recyclable, air and water stable, soluble Ir( iii ) complex, in an ionic liquid, was demonstrated.

Xu Zhang, Siquan Xu, Qinfang Li et al.

RSC Advances • 2021

Furfural is a promising renewable platform molecule derived from hemi-cellulose, which can be further converted to fossil fuel alternatives and valuable chemicals due to its highly functionalized molecular structure.

Andrew C. Marr

Advanced Synthesis & Catalysis • 2024

Abstract This opinionated review underlines the increasing production of 1,3‐propanediol (1,3‐PDO) by whole cell biocatalytic fermentation of biomass and highlights how production has transitioned from petrochemicals to bio‐renewables. Current uses of 1,3‐PDO are listed. Some future prospects for evolving the current technology and expanding the chemical uses of 1,3‐PDO are discussed, with emphasis on catalytic and atom efficient chemistries. Lessons from the success of biomass derived 1,3‐PDO are noted that may be applied to other bio‐based organic platform chemicals.

Urs Hackbarth, Christos Argirusis, Georgia Sourkouni

Journal of Bio-catalysis and Photocatalysis • 2025

Aims: The aim of the present manuscript is the preparation of g-C3N4 using different methods and educts and the use of the prepared materials for the decoloration of dermacid red. Background: Graphitic carbon nitride (g-C3N4) is a promising photocatalytic material due to its unique structural and electronic properties that enhance photocatalytic activity under UV light. Its layered structure and suitable electronic configuration facilitate the generation of reactive species necessary for catalyzing reactions, such as the degradation of azo dyes, organic pollutants, and hydrogen production. Objective: The objective of this research is to evaluate the photocatalytic efficiency of g-C3N4 materials, focusing on the impact of different synthesis and exfoliation methods on their performance, particularly in the degradation of the azo dye Dermacid Red. Method: Characterization techniques such as Powder X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM) were employed to confirm the successful synthesis of the materials and to outline structural differences originating from variations in the synthesis process. The photocatalytic performance was assessed using a customdesigned photocatalytic reactor equipped with UV lamps. Results: The study reveals that photocatalytic efficiency significantly depends on the material's properties, with chemical and ultrasonic exfoliation methods resulting in a substantial increase in efficiency. Notably, after just four minutes of exposure, complete degradation of the azo dye was achieved, highlighting the g-C3N4 material's potential for practical applications in wastewater treatment and environmental remediation processes. Conclusion: The consistent results obtained across varying sample preparations further substantiate the reliability of the synthesized materials. This research contributes valuable insights into the development of effective photocatalysts, paving the way for their integration into various industrial processes aimed at pollution reduction and sustainable practices.

Sophie Hameury, Hana Bensalem, Karine De Oliveira Vigier

Catalysts • 2022

In this review, we aim to give an overview of the use of the Borrowing Hydrogen (BH) methodology with bio-based alcohols. This methodology only forms water as a by-product, thus providing a sustainable way to amines, which have a large range of applications. This process is of particular interest when related to biomass due to the high abundance of alcohol functions in natural compounds. However, natural compounds often comprise multiple chemical functions that can change the reactivity of the substrate. This comprehensive review, comprising both homogeneous and heterogeneous catalysts, aims at summarizing the recent advancements in biomass amination for every class of substrate, highlighting the key parameters governing their reactivity and the remaining scientific hurdles. Even though most substrates have successfully been converted into the corresponding amines, reaction selectivity and functional group tolerance still need to be improved.

Günther Knör

ECS Meeting Abstracts • 2016

Light-induced substrate transformations in artificial photosynthetic devices and functional enzyme model systems strongly depend on the feasibility of multielectron transfer catalysis [1,2]. The crucial advantage of coupling multiple redox equivalents and proton transfer steps in photocatalysis is to avoid free radical reaction pathways and energetic constraints due to charge accumulation, as these processes can decrease both the long-term stability and the efficiency of the corresponding systems. In this context, certain coordination compounds including tetrapyrrole-based derivatives such as porphyrin, corrole and phthalocyanine complexes have been shown to achieve an efficient fusion of the complementary functions of a light-harvester, a photoredox interface, a substrate recognition site and a mediator for chemical reactions [3-6]. To further improve the performance of such systems, the design of long-term stable processes for artificial photosynthetic energy storage and green synthetic chemistry using artificial (photo)enzymes has to be achieved with sustainable, environmentally benign and earth-abundant bulding blocks. Another crucial aspect in the context of solar chemistry and catalysis is not only the requirement for using visible light, but also to shift the threshold wavelength of the photosensitizers as far as possible to the red and NIR-spectral regions. Some of our recent developments in this direction will be presented in this contribution. [1] G. Knör, Chem. Eur. J. 2009 , 15 , 568 [2] G. Knör, Coord. Chem. Rev. 2015 , 304-305 , 102 [3] M. Hajimohammadi, C. Schwarzinger, G. Knör, RSC Advances 2012 , 2 , 3257 [4] C. Uslan, K. T. Oppelt, L. M. Reith, B. Ş. Sesalan, G. Knör, Chem. Commun. 2013 , 49 , 8108 [5] K. T. Oppelt, E. Wöß, M. Stiftinger, W. Schöfberger, W. Buchberger, G. Knör, Inorg. Chem. 2013 , 52 , 11910 [6] M. Ertl, E. Wöß, G. Knör, Photochem. Photobiol. Sci. 2015 , 14 , 1826

Yingxuan Wang

Applied and Computational Engineering • 2025

The creation of efficient water oxidation catalysts (WOCs) is a key area of advancement in sustainable energy researches, particularly for enabling large-scale hydrogen production through water electrolysis. Recent advances in molecular catalyst design have highlighted the prominence of multi-site ruthenium-based systems, with Ru(bda) (bda = 2,2-bipyridine-6,6-dicarboxylate) complexes emerging as a benchmark due to their mechanistic versatility and tunable reactivity. Substantial progress has been achieved through strategic modifications of Ru(bda) catalysts, including dimerization, macrocyclization, and integration into covalent organic frameworks (COFs). Dimeric Ru(bda) systems, for instance, exhibit exceptional turnover frequencies (TOFs) by leveraging intramolecular radical coupling to circumvent the concentration limitations typical of bimolecular O-O bond formation pathways. Meanwhile, macrocyclic Ru(bda) derivatives, inspired by the natural oxygen-evolving complex (OEC), demonstrate enhanced proton-coupled electron transfer (PCET) kinetics, with TOFs reaching 7.9 s-1, attributed to the preorganization of water molecules within their confined cavities. Further innovations include embedding Ru(bda) units into COFs or immobilizing them on carbon nanotubes (CNTs). These hybrid architectures combine the precision of molecular catalysis with the stability of heterogeneous systems, enabling efficient water oxidation via the I2M mechanism. Notably, Ru(bda)-CNT assemblies achieve record-breaking performance with TOFs exceeding 3200 s-1. This review underscores the transformative potential of multi-site Ru(bda) catalysts and outlines a roadmap for rational catalyst design. However, challenges such as long-term stability under oxidative conditions and the scalability of noble-metal-based systems remain to be addressed. Future research directions may focus on elucidating structure-activity relationships and exploring earth-abundant alternatives to further advance practical applications in renewable energy technologies.

Greg Mann, Frédéric V. Stanger

CHIMIA • 2020

Enzymes have the potential to catalyse complex chemical reactions with unprecedented selectivity, under mild conditions in aqueous media. Accordingly, there is serious interest from the pharmaceutical industry to utilize enzymes as biocatalysts to produce medicines in an environmentally sustainable and economic manner. Prominent advances in the field of biotechnology have transformed this potential into a reality. Using modern protein engineering techniques, in a matter of months it is possible to evolve an enzyme, which fits the demands of a chemical process, or even to catalyse entirely novel chemistry. Consequently, biocatalysis is routinely applied throughout the pharmaceutical industry for a variety of applications, ranging from the manufacture of large volumes of high value blockbuster drugs to expanding the chemical space available for drug discovery.

Xia Hua, Jian Han, Xin Zhou et al.

• 2022

Oxygen, as a terminal electron acceptor, is an essential substrate in the aerobic bio-oxidation process, affecting bacterial vitality and bio-oxidation performance. In this study, a new and smart platform biotechnology of sealed-oxygen supply bioreactor (SOS-BR) was developed by improving gas pressure to significantly intensify oxygen transfer rate and resolving the formidable barriers of aerobic catalysis. In virtue of SOS-BR, the bio-productivity was greatly improved for three representative substrates (xylose, furfural, glycerol) bio-oxidation with the whole-cell catalysis of Gluconobacter oxydans. The determination of oxygen transfer coefficient (KLα) established an upgraded theoretical dynamic model for gas pressure intersification biosystem. Additionally, viscosity measurement and combined pressure control strategy explained the inflection point phenomenon of productivity and confirmed the intensify mechanism. The new strategy of significantly intensifying oxygen transfer provided insightful ideas for overcoming the subbon obstacle of obligate aerobic catalysis, and further promoted industrial practicability of bio-oxidation.

Gabriella Garbarino, Giovanni Pampararo, Thanh Khoa Phung et al.

Energies • 2020

In gas/solid conditions, different chemicals, such as diethylether, ethylene, butadiene, higher hydrocarbons, acetaldehyde, acetone and hydrogen, can be produced from ethanol with heterogeneous catalytic processes. The focus of this paper is the interplay of different reaction paths, which depend on thermodynamic factors as well as on kinetic factors, thus mainly from catalyst functionalities and reaction temperatures. Strategies for selectivity improvements in heterogeneously catalyzed processes converting (bio)ethanol into renewable chemicals and biofuels are also considered.

Andree Iemhoff, James Sherwood, Con R. McElroy et al.

Green Chemistry • 2018

The esterification of 2-phenylpropionic acid was investigated as a model system for enzyme catalysed (CALB, Novozyme 435) reactions in bio-based solvents.

Jie Yu

Heterogeneous Catalysis for Energy Applications • 2020

Today, the conversion of biomass in sub- or super-critical water has been extensively studied to produce liquid fuels or synthesis gas (syngas). Given the extreme conditions of water at high pressure and temperature, along with the complex structure of biomass, the development of such processes remains a challenge. In order to realize the complete decomposition of biomass and a high yield of desired products, such as CH4 and H2, at relatively mild conditions, various catalysts have been synthesized and employed. Different metals (such as Cr, Ni, Zn, Ru and Rh) have been incorporated into various supports, such as mineral compounds of Al2O3, SiO2, TiO2, ZrO2, MgO, Y2O3, CeO2, silica-alumina, zeolites and carbon-based supports (e.g. carbon nanotubes, activated carbon). The stability of various support materials and the function of active metals have been extensively tested to obtain an ideal catalyst support. Therefore, this chapter focuses on the discussion of the catalytic gasification of biomass in supercritical water using heterogeneous catalysts. The stability of the catalyst support, the mechanism of cracking, the methanation and water gas shift reaction of intermediates over catalysts and the deactivation of catalysts in supercritical water are discussed.

Mpumelelo T. Matsena, Evans M. N. Chirwa

Scientific Reports • 2021

Abstract The discharge of hexavalent chromium [Cr(VI)] from several anthropogenic activities leads to environmental pollution. In this study, we explore a simple yet cost effective method for the synthesis of palladium (Pd) nanoparticles for the treatment of Cr(VI). The presence of elemental Pd [Pd(0)] was confirmed by scanning electron microscope (SEM), electron dispersive spectroscopy and X-ray diffraction (XRD). We show here that the biologically synthesized nanoparticles (Bio-PdNPs) exhibit improved catalytic reduction of Cr(VI) due to their size being smaller and also being highly dispersed as compared to chemically synthesized nanoparticles (Chem-PdNPs). The Langmuir–Hinshelwood mechanism was successfully used to model the kinetics. Using this model, the Bio-PdNPs were shown to perform better than Chem-PdNPs due to the rate constant (k bio = 6.37 mmol s −1 m −2 ) and Cr(VI) adsorption constant (K Cr(VI),bio = 3.11 × 10 −2 L mmol −1 ) of Bio-PdNPs being higher than the rate constant (k chem = 3.83 mmol s −1 m −2 ) and Cr(VI) adsorption constant (K Cr(VI),chem = 1.14 × 10 −2 L mmol −1 ) of Chem-PdNPs. In addition, product inhibition by trivalent chromium [Cr(III)] was high in Chem-PdNPs as indicated by the high adsorption constant of Cr(III) in Chem-PdNPs of K Cr(III),chem = 52.9 L mmol −1 as compared to the one for Bio-PdNPs of K Cr(III),bio = 2.76 L mmol −1 .

John Warcup Cornforth

Proceedings of the Royal Society of London. Series B. Biological Sciences • 1978

This lecture is a report of progress in work that began at Shell Research Ltd’s Milstead Laboratory and has continued at the University of Sussex. I had spent some ten years studying the substrate sterochemistry of enzymes. No one who has done this could fail to be impressed by the stereochemical precision with which enzymes handle their substrates, even when the nature of the product does not exact a stereospecific treatment. It is hard to resist the conclusion that this specificity is an integral and not an incidental feature of the enormous efficiency of enzymes as catalysts. Naturally, like everyone who has worked with enzymes, I form hypotheses about this or that enzymic catalysis; some of these ideas have been testable by stereochemical methods or by various types of isotopic labelling. Further progress can be, and is being, made by the intensive study of particular enzymes, but to someone like myself who is interested in chemical reactions and chemical synthesis it was more attractive to attempt, on the basis of knowledge and conjecture about the nature of enzymic catalysis, to devise synthetic catalysts having the properties of stereospecificity, positional specificity and high efficiency. Without at present presuming to excel or even equal catalytic powers that are thought to have evolved by trial and error over thousands of millions of years, one can, by making the assumption that catalytic activity of this type is not uniquely a property of proteins, substitute the resources of organic chemistry as a whole for the rigours of polypeptide synthesis.

J. Lubkowski, J. Vanegas, W. Chan et al.

Biochemistry • 2020

Two bacterial type II L-asparaginases, from Escherichia coli and Dickeya chrysanthemi, have been playing a critical role for over 40 years as therapeutic agents against juvenile leukemias and lymphomas. Despite a long history of successful pharmacological applications and apparent simplicity of the catalytic reaction, controversies still exist regarding major steps of the mechanism. In this report, we provide a detailed description of the reaction catalyzed by E. coli type II L-asparaginase (EcAII). Our model was developed based on new structural and biochemical experiments combined with previously published data. The proposed mechanism is supported by quantum chemistry calculations based on density functional theory (DFT). We provide strong evidence that EcAII catalyzes the reaction according to the double-displacement (ping-pong) mechanism, with formation of a covalent intermediate. Several steps of catalysis by EcAII are unique when compared to reactions catalyzed by other known hydrolytic enzymes. Here, the reaction is initiated by a weak nucleophile, threonine, without direct assistance of a general base, although a distant general base is identified. Furthermore, tetrahedral intermediates formed during catalytic process are stabilized by a never previously described motif. Although the scheme of the catalytic mechanism was developed based only on data obtained from EcAII and its variants, this novel mechanism of enzymatic hydrolysis could potentially apply to most (and possibly all) L-asparaginases.

Henrik Almblad, Trevor E Randall, Fanny Liu et al.

Nature Communications • 2021

Many bacteria use the second messenger cyclic diguanylate (c-di-GMP) to control motility, biofilm production and virulence. Here, we identify a thermosensory diguanylate cyclase (TdcA) that modulates temperature-dependent motility, biofilm development and virulence in the opportunistic pathogen Pseudomonas aeruginosa. TdcA synthesizes c-di-GMP with catalytic rates that increase more than a hundred-fold over a ten-degree Celsius change. Analyses using protein chimeras indicate that heat-sensing is mediated by a thermosensitive Per-Arnt-SIM (PAS) domain. TdcA homologs are widespread in sequence databases, and a distantly related, heterologously expressed homolog from the Betaproteobacteria order Gallionellales also displayed thermosensitive diguanylate cyclase activity. We propose, therefore, that thermotransduction is a conserved function of c-di-GMP signaling networks, and that thermosensitive catalysis of a second messenger constitutes a mechanism for thermal sensing in bacteria. Many bacteria use the second messenger cyclic diguanylate (c-di-GMP) to control motility, biofilm production and virulence. Here, the authors identify a thermosensitive enzyme that synthesizes c-di-GMP and modulates temperature-dependent motility, biofilm development and virulence in the opportunistic pathogen Pseudomonas aeruginosa.

Cherian Gloria Susan, Raja Madhan

Journal of Natural Products and Resources • 2021

Tannin degradation by bacteria has not been studied much as tannins are commonly known to be bacteriostatic due to enzyme inhibition, substrate deprivation, and the enzyme activity on the bacterial cell wall. However, about a handful of bacteria have been found to tolerate certain concentrations of tannin. This study focuses on isolating and identifying bacteria from decaying portions of tree bark for tannase production and effective catalysis of ester bond hydrolysis in tannins. Different concentrations of commercial tannic acid were used as the sole carbon source on mineral salt medium (MSM) agar plates, to test the maximum tolerable concentrations (MTCs) by the isolates. Tannin degradation was confirmed by a visual reading method and bacterial tannase activity and the biodegradation percentage were determined. One particular isolate was identified to have 50 g/L MTC of tannin, with a tannase activity of 51.61 U/mL that is optimum after 96 hours of incubation. The 16s rRNA sequencing results showed that the isolate belonged to Bacillus genus and the resulting bacterial strain isolate was found to be a new strain of Bacillus subtilis which was submitted to GenBank under the accession number MH330408.

D. Balchin, M. Hayer-Hartl, F. Hartl

FEBS Letters • 2020

Molecular chaperones are highly conserved proteins that promote proper folding of other proteins in vivo. Diverse chaperone systems assist de novo protein folding and trafficking, the assembly of oligomeric complexes, and recovery from stress‐induced unfolding. A fundamental function of molecular chaperones is to inhibit unproductive protein interactions by recognizing and protecting hydrophobic surfaces that are exposed during folding or following proteotoxic stress. Beyond this basic principle, it is now clear that chaperones can also actively and specifically accelerate folding reactions in an ATP‐dependent manner. We focus on the bacterial Hsp70 and chaperonin systems as paradigms, and review recent work that has advanced our understanding of how these chaperones act as catalysts of protein folding.