Artículos de revistas: "Biocatalyst"

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Cebrián-García, Soledad, Alina Balu, Araceli García y Rafael Luque. "Sol-Gel Immobilisation of Lipases: Towards Active and Stable Biocatalysts for the Esterification of Valeric Acid". Molecules 23, n.º 9 (6 de septiembre de 2018): 2283. http://dx.doi.org/10.3390/molecules23092283.

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Alkyl esters are high added value products useful in a wide range of industrial sectors. A methodology based on a simple sol-gel approach (biosilicification) is herein proposed to encapsulate enzymes in order to design highly active and stable biocatalysts. Their performance was assessed through the optimization of valeric acid esterification evaluating the effect of different parameters (biocatalyst load, presence of water, reaction temperature and stirring rate) in different alcoholic media, and comparing two different methodologies: conventional heating and microwave irradiation. Ethyl valerate yields were in the 80–85% range under optimum conditions (15 min, 12% m/v biocatalyst, molar ratio 1:2 of valeric acid to alcohol). Comparatively, the biocatalysts were slightly deactivated under microwave irradiation due to enzyme denaturalisation. Biocatalyst reuse was attempted to prove that good reusability of these sol-gel immobilised enzymes could be achieved under conventional heating.

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Souza, Priscila M. P., Diego Carballares, Luciana R. B. Gonçalves, Roberto Fernandez-Lafuente y Sueli Rodrigues. "Immobilization of Lipase B from Candida antarctica in Octyl-Vinyl Sulfone Agarose: Effect of the Enzyme-Support Interactions on Enzyme Activity, Specificity, Structure and Inactivation Pathway". International Journal of Molecular Sciences 23, n.º 22 (17 de noviembre de 2022): 14268. http://dx.doi.org/10.3390/ijms232214268.

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Lipase B from Candida antarctica was immobilized on heterofunctional support octyl agarose activated with vinyl sulfone to prevent enzyme release under drastic conditions. Covalent attachment was established, but the blocking step using hexylamine, ethylenediamine or the amino acids glycine (Gly) and aspartic acid (Asp) altered the results. The activities were lower than those observed using the octyl biocatalyst, except when using ethylenediamine as blocking reagent and p-nitrophenol butyrate (pNPB) as substrate. The enzyme stability increased using these new biocatalysts at pH 7 and 9 using all blocking agents (much more significantly at pH 9), while it decreased at pH 5 except when using Gly as blocking agent. The stress inactivation of the biocatalysts decreased the enzyme activity versus three different substrates (pNPB, S-methyl mandelate and triacetin) in a relatively similar fashion. The tryptophane (Trp) fluorescence spectra were different for the biocatalysts, suggesting different enzyme conformations. However, the fluorescence spectra changes during the inactivation were not too different except for the biocatalyst blocked with Asp, suggesting that, except for this biocatalyst, the inactivation pathways may not be so different.

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Gong, Jixian, Tongtong Kong, Yuqiang Li, Qiujin Li, Zheng Li y Jianfei Zhang. "Biodegradation of Microplastic Derived from Poly(ethylene terephthalate) with Bacterial Whole-Cell Biocatalysts". Polymers 10, n.º 12 (30 de noviembre de 2018): 1326. http://dx.doi.org/10.3390/polym10121326.

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At present, the pollution of microplastic directly threatens ecology, food safety and even human health. Polyethylene terephthalate (PET) is one of the most common of microplastics. In this study, the micro-size PET particles were employed as analog of microplastic. The engineered strain, which can growth with PET as sole carbon source, was used as biocatalyst for biodegradation of PET particles. A combinatorial processing based on whole-cell biocatalysts was constructed for biodegradation of PET. Compared with enzymes, the products can be used by strain growth and do not accumulated in culture solution. Thus, feedback inhibition of products can be avoided. When PET was treated with the alkaline strain under high pH conditions, the product concentration was higher and the size of PET particles decreased dramatically than that of the biocatalyst under neutral conditions. This shows that the method of combined processing of alkali and organisms is more efficient for biodegradation of PET. The novel approach of combinatorial processing of PET based on whole-cell biocatalysis provides an attractive avenue for the biodegradation of micplastics.

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Ryan, Jonathon, Hayden Ferral-Smith y Joshua Wilson. "Wastewater and Mixed Microbial Consortia: a metastudy analysis of Optimal Microbial Fuel Cell configuration". PAM Review Energy Science & Technology 5 (31 de mayo de 2018): 22–36. http://dx.doi.org/10.5130/pamr.v5i0.1496.

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Microbial Fuel Cells (MFCs) are an area of increasing research for use as an alternative energy source, due to their ability to produce electricity while simultaneously treating organic waste. This meta-study determines the optimal MFC configuration for electricity production, through consideration of the biocatalyst and substrate used. This study focuses primarily on comparing the use of mixed microbial consortia to pure strains of biocatalyst, and the use of waste water in contrast to simple substrates such as; acetate, glucose, and lactate. The use of algae as a substrate, and as a biocatalyst, is also investigated. In this study, only single and dual chamber MFCs are compared, and power density standardised to anode surface area (mW/m2) is used as a metric to facilitate the comparison of different experimental setups. This meta-study shows that dual chamber MFCs, using simple substrates, when catalysed by mixed culture biocatalysts, produce greater power densities, than algae, and complex substrates, with average power densities of 280, 70 and 30 (mW/m2) observed respectively. In single chamber MFC configurations, mixed culture biocatalysts have been observed to yield approximately double the power output of pure culture biocatalysts.

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Molnár, Zsófia, Emese Farkas, Ágnes Lakó, Balázs Erdélyi, Wolfgang Kroutil, Beáta G. Vértessy, Csaba Paizs y László Poppe. "Immobilized Whole-Cell Transaminase Biocatalysts for Continuous-Flow Kinetic Resolution of Amines". Catalysts 9, n.º 5 (10 de mayo de 2019): 438. http://dx.doi.org/10.3390/catal9050438.

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Immobilization of transaminases creates promising biocatalysts for production of chiral amines in batch or continuous-flow mode reactions. E. coli cells containing overexpressed transaminases of various selectivities and hollow silica microspheres as supporting agent were immobilized by an improved sol-gel process to produce immobilized transaminase biocatalysts with suitable stability and mechanical properties for continuous-flow applications. The immobilized cell-based transaminase biocatalyst proved to be durable and easy-to-use in kinetic resolution of four racemic amines 1a–d. The batch and continuous-flow mode kinetic resolutions with transaminase biocatalyst of opposite stereopreference provided access to both enantiomers of the corresponding amines. By using the most suitable immobilized transaminase biocatalysts, this study describes the first transaminase-based approach for the production of both pure enantiomers of 1-(3,4-dimethoxyphenyl)ethan-1-amine 1d.

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Szelwicka, Anna, Anna Wolny, Miroslawa Grymel, Sebastian Jurczyk, Slawomir Boncel y Anna Chrobok. "Chemo-Enzymatic Baeyer–Villiger Oxidation Facilitated with Lipases Immobilized in the Supported Ionic Liquid Phase". Materials 14, n.º 13 (22 de junio de 2021): 3443. http://dx.doi.org/10.3390/ma14133443.

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A novel method for chemo-enzymatic Baeyer–Villiger oxidation of cyclic ketones in the presence of supported ionic liquid-like phase biocatalyst was designed. In this work, multi-walled carbon nanotubes were applied as a support for ionic liquids which were anchored to nanotubes covalently by amide or imine bonds. Next, lipases B from Candida antarctica, Candida rugosa, or Aspergillus oryzae were immobilized on the prepared materials. The biocatalysts were characterized using various techniques, like thermogravimetry, IR spectroscopy, XPS, elemental analysis, and SEM-EDS microscopy. In the proposed approach, a biocatalyst consisting of a lipase as an active phase allowed the generation of peracid in situ from the corresponding precursor and a green oxidant–hydrogen peroxide. The activity and stability of the obtained biocatalysts in the model oxidation of 2-adamantanone were demonstrated. High conversion of substrate (92%) was achieved under favorable conditions (toluene: n-octanoic acid ratio 1:1 = v:v, 35% aq. H2O2 2 eq., 0.080 g of biocatalyst per 1 mmol of ketone at 20 °C, reaction time 4 h) with four reaction cycles without a drop in its activity. Our ‘properties-by-design’ approach is distinguished by its short reaction time at low temperature and higher thermal stability in comparison with other biocatalysts presented in the literature reports.

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He, Qiyang, Hao Shi, Huaxiang Gu, Gilda Naka, Huaihai Ding, Xun Li, Yu Zhang, Bo Hu y Fei Wang. "Immobilization of Rhizopus oryzae LY6 onto Loofah Sponge as a Whole-Cell Biocatalyst for Biodiesel Production". BioResources 11, n.º 1 (30 de noviembre de 2015): 850–60. http://dx.doi.org/10.15376/biores.11.1.850-860.

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Whole cell biocatalysts for biodiesel production have garnered significant attention in recent years, as they can help avoid the complex procedures of isolation, purification, and immobilization of extracellular lipase. Because of its renewability and biodegradability, loofah (Luffa cylindrica) sponge is an advantageous substitute for traditional biomass carriers in whole cell immobilization. Rhizopus oryzae mycelia can spontaneously attach onto loofah sponge particles (LSPs) during cell cultivation. The highest immobilized R. oryzae cells concentration can reach up to 1.40 g/1 g of LSPs. The effects of biocatalyst addition and water content on methanolysis for biodiesel production were investigated in this paper. The operational stability of glutaraldehyde-treated biocatalyst at 35 °C, using a 1:1 oil-to-methanol ratio, was assayed, revealing a 3.4-fold increase in half-life compared with the untreated biocatalyst. Under optimized conditions, the yield of methyl esters in the reaction mixture reached 82.2% to 92.2% in each cycle. These results suggested that loofah sponge is a potential fungi carrier for an immobilized whole-cell biocatalyst.

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Ripoll, Magdalena, Nicolás Soriano, Sofía Ibarburu, Malena Dalies, Ana Paula Mulet y Lorena Betancor. "Bacteria-Polymer Composite Material for Glycerol Valorization". Polymers 15, n.º 11 (30 de mayo de 2023): 2514. http://dx.doi.org/10.3390/polym15112514.

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Bacterial immobilization is regarded as an enabling technology to improve the stability and reusability of biocatalysts. Natural polymers are often used as immobilization matrices but present certain drawbacks, such as biocatalyst leakage and loss of physical integrity upon utilization in bioprocesses. Herein, we prepared a hybrid polymeric matrix that included silica nanoparticles for the unprecedented immobilization of the industrially relevant Gluconobacter frateurii (Gfr). This biocatalyst can valorize glycerol, an abundant by-product of the biodiesel industry, into glyceric acid (GA) and dihydroxyacetone (DHA). Different concentrations of siliceous nanosized materials, such as biomimetic Si nanoparticles (SiNps) and montmorillonite (MT), were added to alginate. These hybrid materials were significantly more resistant by texture analysis and presented a more compact structure as seen by scanning electron microscopy. The preparation including 4% alginate with 4% SiNps proved to be the most resistant material, with a homogeneous distribution of the biocatalyst in the beads as seen by confocal microscopy using a fluorescent mutant of Gfr. It produced the highest amounts of GA and DHA and could be reused for up to eight consecutive 24 h reactions with no loss of physical integrity and negligible bacterial leakage. Overall, our results indicate a new approach to generating biocatalysts using hybrid biopolymer supports.

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Trawczyńska, Ilona. "Immobilization of permeabilized cells of baker’s yeast for decomposition of H2O2 by catalase". Polish Journal of Chemical Technology 21, n.º 2 (1 de junio de 2019): 59–63. http://dx.doi.org/10.2478/pjct-2019-0021.

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Abstract Permeabilization is one of the effective tools, used to increase the accessibility of intracellular enzymes. Immobilization is one of the best approaches to reuse the enzyme. Present investigation use both techniques to obtain a biocatalyst with high catalase activity. At the beginning the isopropyl alcohol was used to permeabilize cells of baker’s yeast in order to maximize the catalase activity within the treated cells. Afterwards the permeabilized cells were immobilized in calcium alginate beads and this biocatalyst was used for the degradation of hydrogen peroxide to oxygen and water. The optimal sodium alginate concentration and cell mass concentration for immobilization process were determined. The temperature and pH for maximum decomposition of hydrogen peroxide were assigned and are 20°C and 7 respectively. Prepared biocatalyst allowed 3.35-times faster decomposition as compared to alginate beads with non permeabilized cells. The immobilized biocatalyst lost ca. 30% activity after ten cycles of repeated use in batch operations. Each cycles duration was 10 minutes. Permeabilization and subsequent immobilization of the yeast cells allowed them to be transformed into biocatalysts with an enhanced catalase activity, which can be successfully used to decompose hydrogen peroxide.

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Travalia, Beatriz Medeiros, Mercia Galvão, Alvaro Silva Lima, Cleide Mara Faria Soares, Narendra Narain y Luciana Cristina Lins de Aquino Santana. "Effect of parameters on butyl butyrate synthesis using novel Aspergillus niger lipase as biocatalyst". Acta Scientiarum. Technology 40, n.º 1 (1 de julio de 2018): 35999. http://dx.doi.org/10.4025/actascitechnol.v40i1.35999.

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A novel “green” Aspergillus niger lipase, obtained from the fermentation of pumpkin seeds, was used in a free form and encapsulated in sol-gel matri x in butyl butyrate (pineapple flavor) synthesis. Esterification reactions were performed with varying substrate molar ratio (butanol: butyric acid) ranging between 1:1 and 5:1; temperature between 30 and 60°C and biocatalyst mass between 0 and 1g, respectively, according to experimental design 23 with 6 axial and 3 central points. Maximum butyl butyrate production was obtained when substrate molar ratio (butanol:butyric acid) 3:1, temperature at 60°C and 0.5 g free or encapsulated lipase as biocatalyst, were used. Temperature was the most significant parameter for production with the two biocatalysts, indicating that higher rates mean greater compound synthesis. Response surface plots showed that higher butyl butyrate production may be obtained with higher temperature and molar ratio rates (butanol:butyric acid) and with lower rates of biocatalyst mass in reactions catalyzed by free or encapsulated lipase. Aspergillus niger lipase obtained from agro-industrial waste could be employed as biocatalyst in esterification reactions in the production of natural aroma as butyl butyrate.

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Melis, Roberta, Elena Rosini, Valentina Pirillo, Loredano Pollegioni y Gianluca Molla. "In vitro evolution of an l-amino acid deaminase active on l-1-naphthylalanine". Catalysis Science & Technology 8, n.º 20 (2018): 5359–67. http://dx.doi.org/10.1039/c8cy01380b.

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Jarboe, Laura R., Xueli Zhang, Xuan Wang, Jonathan C. Moore, K. T. Shanmugam y Lonnie O. Ingram. "Metabolic Engineering for Production of Biorenewable Fuels and Chemicals: Contributions of Synthetic Biology". Journal of Biomedicine and Biotechnology 2010 (2010): 1–18. http://dx.doi.org/10.1155/2010/761042.

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Production of fuels and chemicals through microbial fermentation of plant material is a desirable alternative to petrochemical-based production. Fermentative production of biorenewable fuels and chemicals requires the engineering of biocatalysts that can quickly and efficiently convert sugars to target products at a cost that is competitive with existing petrochemical-based processes. It is also important that biocatalysts be robust to extreme fermentation conditions, biomass-derived inhibitors, and their target products. Traditional metabolic engineering has made great advances in this area, but synthetic biology has contributed and will continue to contribute to this field, particularly with next-generation biofuels. This work reviews the use of metabolic engineering and synthetic biology in biocatalyst engineering for biorenewable fuels and chemicals production, such as ethanol, butanol, acetate, lactate, succinate, alanine, and xylitol. We also examine the existing challenges in this area and discuss strategies for improving biocatalyst tolerance to chemical inhibitors.

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Szelwicka, Anna, Karol Erfurt, Sebastian Jurczyk, Slawomir Boncel y Anna Chrobok. "Outperformance in Acrylation: Supported D-Glucose-Based Ionic Liquid Phase on MWCNTs for Immobilized Lipase B from Candida antarctica as Catalytic System". Materials 14, n.º 11 (4 de junio de 2021): 3090. http://dx.doi.org/10.3390/ma14113090.

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This study presents a highly efficient method of a synthesis of n-butyl acrylate via esterification of acrylic acid and n-butanol in the presence of supported ionic liquid phase (SILP) biocatalyst consisting of the lipase B from Candida antarctica (CALB) and multi-walled carbon nanotubes (MWCNTs) modified by D-glucose-based ionic liquids. Favorable reaction conditions (acrylic acid: n-butanol molar ratio 1:2, cyclohexane as a solvent, biocatalyst 0.150 g per 1 mmol of acrylic acid, temperature 25 °C) allowed the achievement of a 99% yield of n-butyl acrylate in 24 h. Screening of various ionic liquids showed that the most promising result was obtained if N-(6-deoxy-1-O-methoxy-α-D-glucopyranosyl)-N,N,N-trimethylammonium bis-(trifluoromethylsulfonyl)imide ([N(CH3)3GlcOCH3][N(Tf)2]) was selected in order to modify the outer surface of MWCNTs. The final SILP biocatalyst–CNTs-[N(CH3)3GlcOCH3][N(Tf)2]-CALB contained 1.8 wt.% of IL and 4.2 wt.% of CALB. Application of the SILP biocatalyst led to the enhanced activity of CALB in comparison with the biocatalyst prepared via physical adsorption of CALB onto MWCNTs (CNTs-CALB), as well as with commercially available Novozyme 435. Thus, the crucial role of IL in the stabilization of biocatalysts was clearly demonstrated. In addition, a significant stability of the developed biocatalytic system was confirmed (three runs with a yield of ester over 90%).

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Lajtai-Szabó, Piroska, Tímea Brigitta Bagó y Nándor Nemestóthy. "Production of Chiral (S)-2-Phenyl-1-Propanol by Enantioselective Biocatalysts". Hungarian Journal of Industry and Chemistry 50, n.º 1 (27 de septiembre de 2022): 23–28. http://dx.doi.org/10.33927/hjic-2022-05.

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Enantioselective production of (S)-2-phenyl-1-propanol is important as in order to be applied in industry, a high degree of optical purity is required. Besides organocatalysts and metal complexes, biocatalysts can be used for its synthesis in their isolated form or as whole-cell biocatalysts, both of which have various advantages and disadvantages. In this research, Saccharomyces cerevisiae, as a whole-cell biocatalyst, and recombinant horse-liver alcohol dehydrogenase (ADH), as an isolated enzyme, were investigated in terms of their activity, kinetics and enantioselectivity. In the case of yeast, therate of cofactor regeneration was twice that of substrate conversion, moreover, the biocatalyst Saccharomyces cerevisiae can be characterised by substrate-limited kinetics and low nantioselectivity. In contrast, the isolated enzyme recombinant horse-liver ADH exhibited biphasic kinetics and cofactor regeneration was the rate-limiting step. The outstanding enantioselectivity of recombinant horse-liver ADH renders it a promising catalyst for the purpose of this synthesis.

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Zulaika, Aidha, Sari Sekar Ningrum y Dody Guntama. "Preliminary Study of Actinomycetes as Potential Biocatalyst in Biodiesel Production Through Microbial Lipase Activity". Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan 18, n.º 3 (29 de septiembre de 2021): 512–23. http://dx.doi.org/10.14710/presipitasi.v18i3.512-523.

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Biocatalysts are biological substances that act as an accelerator of chemical reactions without causing influence on the living organism chemically. Biocatalysts based on renewable sources, biodegradable, tolerance to pH and temperature, and high selectivity to stereochemistry substrates and products. The utilization of biocatalyst is environmentally friendly and effective in production costs. This research aimed to determine the potential of actinomycetes as a biocatalyst in biodiesel production. This research method isolation and identification of actinomycetes isolates, conducting lipase activity test to determining lipase enzyme production of actinomycetes isolates. The data analysis in microbial identification was conducted by molecular identification by Gene bank through Basic Local Alignment Search Tool (BLAST). The lipase activity of actinomycetes analyzing by the value of lipase rate of test microbes. Based on chemical analysis of lipase activity, this research results show that actinomycetes T1A has the highest lipase activity by 14.4640 mU/g. Based on molecular identification analysis, actinomycetes T1A was identified as Streptomyces sp., 99% similar to Streptomyces phaeochromogenes.

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Bié, Joaquim, Bruno Sepodes, Pedro C. B. Fernandes y Maria H. L. Ribeiro. "Enzyme Immobilization and Co-Immobilization: Main Framework, Advances and Some Applications". Processes 10, n.º 3 (1 de marzo de 2022): 494. http://dx.doi.org/10.3390/pr10030494.

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Enzymes are outstanding (bio)catalysts, not solely on account of their ability to increase reaction rates by up to several orders of magnitude but also for the high degree of substrate specificity, regiospecificity and stereospecificity. The use and development of enzymes as robust biocatalysts is one of the main challenges in biotechnology. However, despite the high specificities and turnover of enzymes, there are also drawbacks. At the industrial level, these drawbacks are typically overcome by resorting to immobilized enzymes to enhance stability. Immobilization of biocatalysts allows their reuse, increases stability, facilitates process control, eases product recovery, and enhances product yield and quality. This is especially important for expensive enzymes, for those obtained in low fermentation yield and with relatively low activity. This review provides an integrated perspective on (multi)enzyme immobilization that abridges a critical evaluation of immobilization methods and carriers, biocatalyst metrics, impact of key carrier features on biocatalyst performance, trends towards miniaturization and detailed illustrative examples that are representative of biocatalytic applications promoting sustainability.

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de Gonzalo, Gonzalo. "Biocatalyzed Sulfoxidation in Presence of Deep Eutectic Solvents". Sustainable Chemistry 1, n.º 3 (12 de noviembre de 2020): 290–97. http://dx.doi.org/10.3390/suschem1030019.

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The flavin-containing monooxygenase from Methylophaga sp. strain SK1 (mFMO) is a valuable biocatalyst for the preparation of optically active sulfoxides, among other valuable compounds. In this study, we explored to benefits of using Natural Deep Eutectic Solvents (NADESs) when doing oxidation with this biocatalyst, fused to phosphite dehydrogenase for cofactor regeneration (PTDH-mFMO). It was found that optically active sulfoxides could be obtained with slightly higher conversions in 10% v/v NADES when working at substrate concentrations of 50–200 mM, whereas there was no loss in the enantioselectivity. With these results, it is demonstrated for the first time that flavin-containing monooxygenases can be employed as biocatalysts in presence of NADESs.

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Dias Gomes, Mafalda y John M. Woodley. "Considerations when Measuring Biocatalyst Performance". Molecules 24, n.º 19 (3 de octubre de 2019): 3573. http://dx.doi.org/10.3390/molecules24193573.

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As biocatalysis matures, it becomes increasingly important to establish methods with which to measure biocatalyst performance. Such measurements are important to assess immobilization strategies, different operating modes, and reactor configurations, aside from comparing protein engineered variants and benchmarking against economic targets. While conventional measurement techniques focus on a single performance metric (such as the total turnover number), here, it is argued that three metrics (achievable product concentration, productivity, and enzyme stability) are required for an accurate assessment of scalability.

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Alcántara, Andrés R. "Biocatalysis and Pharmaceuticals: A Smart Tool for Sustainable Development". Catalysts 9, n.º 10 (23 de septiembre de 2019): 792. http://dx.doi.org/10.3390/catal9100792.

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Biocatalysis is the term used to describe the application of any type of biocatalyst (enzymes, as isolated preparations of wild-type or genetically modified variants, or whole cells, either as native cells or as recombinant expressed proteins inside host cells) in a given synthetic schedule [...]

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Muñoz-Morales, Emilio, Susana Velasco-Lozano, Ana I. Benítez-Mateos, María J. Marín, Pedro Ramos-Cabrer y Fernando López-Gallego. "Deciphering the Effect of Microbead Size Distribution on the Kinetics of Heterogeneous Biocatalysts through Single-Particle Analysis Based on Fluorescence Microscopy". Catalysts 9, n.º 11 (28 de octubre de 2019): 896. http://dx.doi.org/10.3390/catal9110896.

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Understanding the functionality of immobilized enzymes with spatiotemporal resolution and under operando conditions is an unmet need in applied biocatalysis, as well as priceless information to guide the optimization of heterogeneous biocatalysts for industrial purposes. Unfortunately, enzyme immobilization still relies on trial-and-error approximations that prevail over rational designs. Hence, a modern fabrication process to achieve efficient and robust heterogeneous biocatalysts demands comprehensive characterization techniques to track and understand the immobilization process at the protein–material interface. Recently, our group has developed a new generation of self-sufficient heterogeneous biocatalysts based on alcohol dehydrogenases co-immobilized with nicotinamide cofactors on agarose porous microbeads. Harnessing the autofluorescence of NAD+(P)H and using time-lapse fluorescence microscopy, enzyme activity toward the redox cofactors can be monitored inside the beads. To analyze these data, herein we present an image analytical tool to quantify the apparent Michaelis–Menten parameters of alcohol dehydrogenases co-immobilized with NAD(P)+/H at the single-particle level. Using this tool, we found a strong negative correlation between the apparent catalytic performance of the immobilized enzymes and the bead radius when using exogenous bulky substrates in reduction reactions. Therefore, applying image analytics routines to microscopy studies, we can directly unravel the functional heterogeneity of different heterogeneous biocatalyst samples tested under different reaction conditions.

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Hermansyah, Heri, Septian Marno, Rita Arbianti, Tania Surya Utami y Anandho Wijanarko. "Sintesis biodiesel rute non-alkohol menggunakan Candida rugosa lipase dalam bentuk tersuspensi". Jurnal Teknik Kimia Indonesia 8, n.º 2 (2 de octubre de 2018): 38. http://dx.doi.org/10.5614/jtki.2009.8.2.1.

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Non-alcoholic route biodiesel synthesis using suspended Candida rugosa lipaseBiodiesel synthesis using biocatalyst can improve the disadvantage of alkali catalyst. Biocatalysts are not homogeneously mixed, so its separation is easy and it is also able to direct the reaction specifically without any unwanted side reactions. However, the application of biocatalysts in alcoholic environment degrades the biocatalyst quickly, and its stability suffers. To solve this problem, this research proposes to perform biodiesel synthesis through a non-alcohol route so that the activity and stability of the biocatalyst can be preserved. The biocatalyst used was Candida rugosa lipase in suspended form. Methyl acetate which served as alkyl group source was reacted with triglycerides from palm oil. The reaction was performed in a batch reactor, and HPLC was used to analyze reactants and product concentrations. Research results indicated that more than 86% of fatty acid chains from the palm oil triglycerides were converted to biodiesel at a biocatalyst concentration of 4 %-wt of the substrate, oil:alkyl molar ratio of 1:12, and reaction period of 50 hours. Furthermore, the kinetic data obtained using suspended enzyme, were also shown by concentration profile of tri-, di-, monoglycerides and biodiesel versus time in 50 hours reaction time.Keywords: biodiesel synthesis, interesterification, Candida rugosa lipase, non-alcohol route, triglycerideAbstrakSintesis biodiesel menggunakan biokatalis mampu memperbaiki kelemahan katalis alkali, yaitu tidak bercampur homogen, sehingga pemisahannya mudah dan mampu mengarahkan reaksi secara spesifik tanpa adanya reaksi samping yang tidak diinginkan. Namun penggunaan biokatalis di lingkungan beralkohol menyebabkan biokatalis terdeaktivasi secara cepat dan stabilitasnya menjadi buruk. Untuk menyelesaikan masalah tersebut, dalam riset ini diusulkan melakukan sintesis biodiesel melalui rute non-alkohol agar aktivitas dan stabilitas biokatalis tetap tinggi. Biokatalis yang digunakan adalah Candida rugosa lipase dalam bentuk tersuspensi. Metil asetat sebagai pensuplai gugus alkil direaksikan dengan trigliserida dari minyak kelapa sawit. Reaksi dilakukan dalam reaktor batch dan HPLC digunakan untuk menganalisa reaktan dan produk. Hasil penelitian menunjukkan bahwa lebih dari 86% rantai asam lemak dari trigliserida minyak kelapa sawit berhasil di konversikan menjadi biodiesel pada kondisi konsentrasi biokatalis sebesar 4 %-wt substrat, rasio mol minyak:alkil sebesar 1:12 selama 50 jam reaksi. Selanjutnya, data kinetika menggunakan enzim tersuspensi juga ditunjukkan melalui profil konsentrasi tri-, di-, mono, dan biodiesel terhadap waktu selama 50 jam.Kata Kunci: sintesis biodiesel, interesterifikasi, Candida rugosa lipase, rute non-alkohol, trigliserida

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Tacias-Pascacio, Ortiz, Rueda, Berenguer-Murcia, Acosta, Aranaz, Civera, Fernandez-Lafuente y Alcántara. "Dextran Aldehyde in Biocatalysis: More Than a Mere Immobilization System". Catalysts 9, n.º 7 (21 de julio de 2019): 622. http://dx.doi.org/10.3390/catal9070622.

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Dextran aldehyde (dexOx), resulting from the periodate oxidative cleavage of 1,2-diol moiety inside dextran, is a polymer that is very useful in many areas, including as a macromolecular carrier for drug delivery and other biomedical applications. In particular, it has been widely used for chemical engineering of enzymes, with the aim of designing better biocatalysts that possess improved catalytic properties, making them more stable and/or active for different catalytic reactions. This polymer possesses a very flexible hydrophilic structure, which becomes inert after chemical reduction; therefore, dexOx comes to be highly versatile in a biocatalyst design. This paper presents an overview of the multiple applications of dexOx in applied biocatalysis, e.g., to modulate the adsorption of biomolecules on carrier surfaces in affinity chromatography and biosensors design, to serve as a spacer arm between a ligand and the support in biomacromolecule immobilization procedures or to generate artificial microenvironments around the enzyme molecules or to stabilize multimeric enzymes by intersubunit crosslinking, among many other applications.

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23

Sousa, Ronaldo Rodrigues de, Ayla Sant’Ana da Silva, Roberto Fernandez-Lafuente y Viridiana Santana Ferreira-Leitão. "Simplified Method to Optimize Enzymatic Esters Syntheses in Solvent-Free Systems: Validation Using Literature and Experimental Data". Catalysts 11, n.º 11 (12 de noviembre de 2021): 1357. http://dx.doi.org/10.3390/catal11111357.

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The adoption of biocatalysis in solvent-free systems is an alternative to establish a greener esters production. An interesting correlation between the acid:alcohol molar ratio and biocatalyst (immobilized lipase) loading in the optimization of ester syntheses in solvent-free systems had been observed and explored. A simple mathematical tool named Substrate-Enzyme Relation (SER) has been developed, indicating a range of reaction conditions that resulted in high conversions. Here, SER utility has been validated using data from the literature and experimental assays, totalizing 39 different examples of solvent-free enzymatic esterifications. We found a good correlation between the SER trends and reaction conditions that promoted high conversions on the syntheses of short, mid, or long-chain esters. Moreover, the predictions obtained with SER are coherent with thermodynamic and kinetics aspects of enzymatic esterification in solvent-free systems. SER is an easy-to-handle tool to predict the reaction behavior, allowing obtaining optimum reaction conditions with a reduced number of experiments, including the adoption of reduced biocatalysts loadings.

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24

de Freitas, Lucas A., Marylane de Sousa, Laiza B. Ribeiro, Ítalo W. L. de França y Luciana R. B. Gonçalves. "Magnetic CLEAs of β-Galactosidase from Aspergillus oryzae as a Potential Biocatalyst to Produce Tagatose from Lactose". Catalysts 13, n.º 2 (30 de enero de 2023): 306. http://dx.doi.org/10.3390/catal13020306.

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β-galactosidase is an enzyme capable of hydrolysing lactose, used in various branches of industry, mainly the food industry. As the efficient industrial use of enzymes depends on their reuse, it is necessary to find an effective method for immobilisation, maintaining high activity and stability. The present work proposes cross-linked magnetic cross-linked enzyme aggregates (mCLEAs) to prepare heterogeneous biocatalysts of β-galactosidase. Different concentrations of glutaraldehyde (0.6%, 1.0%, 1.5%), used as a cross-linking agent, were studied. The use of dextran-aldehyde as an alternative cross-linking agent was also evaluated. The mCLEAs presented increased recovered activity directly related to the concentration of glutaraldehyde. Modifications to the protocol to prepare mCLEAs with glutaraldehyde, adding a competitive inhibitor or polymer coating, have not been effective in increasing the recovered activity of the heterogeneous biocatalysts or its thermal stability. The biocatalyst prepared using dextran-aldehyde presented 73.6% recovered activity, aside from substrate affinity equivalent to the free enzyme. The thermal stability at 60 °C was higher for the biocatalyst prepared with glutaraldehyde (mCLEA-GLU-1.5) than the one produced with dextran-aldehyde (mCLEA-DEX), and the opposite happened at 50 °C. Results obtained for lactose hydrolysis, the use of its product to produce a rare sugar (D-tagatose) and operational and storage stability indicate that heterogeneous biocatalysts have adequate characteristics for industrial use.

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25

Cheng, Lei, Dian Li, Binh Khanh Mai, Zhiyu Bo, Lida Cheng, Peng Liu y Yang Yang. "Stereoselective amino acid synthesis by synergistic photoredox-pyridoxal radical biocatalysis". Science 381, n.º 6656 (28 de julio de 2023): 444–51. http://dx.doi.org/10.1126/science.adg2420.

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Developing synthetically useful enzymatic reactions that are not known in biochemistry and organic chemistry is an important challenge in biocatalysis. Through the synergistic merger of photoredox catalysis and pyridoxal 5′-phosphate (PLP) biocatalysis, we developed a pyridoxal radical biocatalysis approach to prepare valuable noncanonical amino acids, including those bearing a stereochemical dyad or triad, without the need for protecting groups. Using engineered PLP enzymes, either enantiomeric product could be produced in a biocatalyst-controlled fashion. Synergistic photoredox - pyridoxal radical biocatalysis represents a powerful platform with which to discover previously unknown catalytic reactions and to tame radical intermediates for asymmetric catalysis.

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Baruque, Julia R. S., Adriano Carniel, Júlio C. S. Sales, Bernardo D. Ribeiro, Rodrigo P. do Nascimento y Ivaldo Itabaiana. "Immobilization of Cellulolytic Enzymes in Accurel® MP1000". Reactions 4, n.º 2 (16 de junio de 2023): 311–28. http://dx.doi.org/10.3390/reactions4020019.

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Cellulases are a class of enzymes of great industrial interest that present several strategic applications. However, the high cost of enzyme production, coupled with the instabilities and complexities of proteins required for hydrolytic processes, still limits their use in several protocols. Therefore, enzyme immobilization may be an essential tool to overcome these issues. The present work aimed to evaluate the immobilization of cellulolytic enzymes of the commercial enzyme cocktail Celluclast® 1.5 L in comparison to the cellulolytic enzyme cocktail produced from the wild strain Trichoderma harzianum I14-12 in Accurel® MP1000. Among the variables studied were temperature at 40 °C, ionic strength of 50 mM, and 72 h of immobilization, with 15 m·L −1 of proteins generated biocatalysts with high immobilization efficiencies (87% for ACC-Celluclast biocatalyst and 95% for ACC-ThI1412 biocatalyst), high retention of activity, and specific activities in the support for CMCase (DNS method), FPase (filter paper method) and β-glucosidase (p-nitrophenyl-β-D-glucopyranoside method). Presenting a lower protein concentration (0.32 m·L−1) than the commercial Celluclast® 1.5 L preparation (45 m·L−1), the ACC-ThI1412-derived immobilized biocatalyst showed thermal stability at temperatures higher than 60 °C, maintaining more than 90% of the residual activities of FPase, CMCase, and β-glucosidase. In contrast, the commercial-free enzyme presented a maximum catalytic activity at only 40 °C. Moreover, the difference in molecular weight between the component enzymes of the extract was responsible for different hydrophobic and lodging interactions of proteins on the support, generating a robust and competitive biocatalyst.

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Ion, Sabina, Florentina Olănescu, Florina Teodorescu, Robert Tincu, Daniela Gheorghe, Vasile I. Pârvulescu y Mădălina Tudorache. "DES-Based Biocatalysis as a Green Alternative for the l-menthyl Ester Production Based on l-menthol Acylation". Molecules 27, n.º 16 (18 de agosto de 2022): 5273. http://dx.doi.org/10.3390/molecules27165273.

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The deep eutectic solvent (DES)-based biocatalysis of l-menthol acylation was designed for the production of fatty acid l-menthyl ester (FME) using fatty acid methyl ester (FAME). The biocatalytic reaction was assisted by a lipase enzyme in the DES reaction medium. ւՒ-menthol and fatty acids (e.g., CA—caprylic acid; OA—oleic acid; LiA—linoleic acid; and LnA—linolenic acid) were combined in the binary mixture of DES. In this way, the DES provided a nonpolar environment for requested homogeneity of a biocatalytic system with reduced impact on the environment. The screening of lipase enzyme demonstrated better performance of immobilized lipase compared with powdered lipase. The performance of the biocatalytic system was evaluated for different DES compositions (type and concentration of the acid component). l-menthol:CA = 73:27 molar ratio allowed it to reach a maximum conversion of 95% methyl lauric ester (MLE) using a NV (Candida antarctica lipase B immobilized on acrylic resin) lipase biocatalyst. The recyclability of biocatalysts under optimum conditions of the system was also evaluated (more than 80% recovered biocatalytic activity was achieved for the tested biocatalysts after five reaction cycles). DES mixtures were characterized based on differential scanning calorimetry (DSC) and refractive index analysis.

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Menossi, Ribeiro, Leandro da Rin de Sandre, Giancarlo de Souza Dias, Michelle da Cunha Abreu Xavier, Alex de Almeida, Elda da Silva, Alfredo Maiorano, Rafael Firmani Perna y Sergio Andres Villalba Morales. "Crosslinked whole cells for the sucrose transfructosylation reaction in a continuous reactor". Chemical Industry and Chemical Engineering Quarterly, n.º 00 (2023): 15. http://dx.doi.org/10.2298/ciceq221220015m.

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Fructooligosaccharides (FOS) are fructose oligomers that are beneficial to human health and nutrition for being prebiotic sugars. Their production occurs by a transfructosylation reaction in sucrose molecules catalyzed by fructosyltransferase enzymes (FTase, E.C.2.4.1.9) adhered to microbial cells. The purpose of this work was to study the preparation, enzymatic activity, and stability of glutaraldehyde-crosslinked Aspergillus oryzae IPT-301 cells used as biocatalyst for the transfructosylation reaction of sucrose in a packed bed reactor (PBR), aiming at FOS production. The highest transfructosylation activity (AT) was presented by the biocatalyst prepared by crosslinking at 200 rpm and 45 min. The highest AT in the PBR were obtained at 50?C, flow rates from 3 mL min-1 to 5 mL min-1 and sucrose concentrations of 473 g L-1 and 500 g L-1. The enzymatic kinetics was described using the Michaelis-Menten model. Finally, the biocatalyst showed constant AT of approximately 75 U g-1 and 300 U g-1 for 12 h of reaction in the PBR operating in continuous and discontinuous flow, respectively. These results demonstrate a high potential of glutaraldehyde-crosslinked A. oryzae IPT-301 cells as heterogeneous biocatalysts for the continuous production of FOS in PBR reactors.

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Montiel, Claudia, Silvia Gimeno-Martos, Salvadora Ortega-Requena, Mar Serrano-Arnaldos, Fuensanta Máximo y Josefa Bastida. "Green Production of a High-Value Branched-Chain Diester: Optimization Based on Operating Conditions and Economic and Sustainability Criteria". Applied Sciences 13, n.º 10 (18 de mayo de 2023): 6177. http://dx.doi.org/10.3390/app13106177.

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Branched-chain esters (BCEs) have found a large number of applications in cosmetics. Among them, neopentyl glycol dilaurate (NPGDL) stands out as an emollient, emulsifier, and skin-conditioning agent. This work presents the synthesis of NPGDL in a solvent-free medium using the two most common immobilized lipases: Novozym® 40086 (Rml) and Novozym® 435 (CalB). Results proved that the former biocatalyst has lower activity and certain temperature deactivation, although conversions ≥ 90% were obtained at 60 °C and 7.5% of catalyst. On the other hand, optimal reaction conditions for Novozym® 435 are 3.75% w/w of the immobilized derivative at 80 °C. Under optimal conditions, the process productivities were 0.105 and 0.169 kg NPGDL/L h, respectively. In order to select the best conditions for NPGDL production, studies on the reuse of the derivative and cost estimation have been performed. Economic study shows that biocatalytic processes can be competitive when lipases are reused for five cycles, yielding biocatalyst productivities of 56 and 122 kg NPGDL/kg biocatalyst using Novozym® 40086 and Novozym® 435, respectively. The final choice will be based on both economic and sustainability criteria. Green metric values using both biocatalysts are similar but the product obtained using Novozym® 40086 is 20% cheaper, making this alternative the best option.

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Sampaio, Pedro Sousa y Pedro Fernandes. "Machine Learning: A Suitable Method for Biocatalysis". Catalysts 13, n.º 6 (1 de junio de 2023): 961. http://dx.doi.org/10.3390/catal13060961.

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Biocatalysis is currently a workhorse used to produce a wide array of compounds, from bulk to fine chemicals, in a green and sustainable manner. The success of biocatalysis is largely thanks to an enlargement of the feasible chemical reaction toolbox. This materialized due to major advances in enzyme screening tools and methods, together with high-throughput laboratory techniques for biocatalyst optimization through enzyme engineering. Therefore, enzyme-related knowledge has significantly increased. To handle the large number of data now available, computational approaches have been gaining relevance in biocatalysis, among them machine learning methods (MLMs). MLMs use data and algorithms to learn and improve from experience automatically. This review intends to briefly highlight the contribution of biocatalysis within biochemical engineering and bioprocesses and to present the key aspects of MLMs currently used within the scope of biocatalysis and related fields, mostly with readers non-skilled in MLMs in mind. Accordingly, a brief overview and the basic concepts underlying MLMs are presented. This is complemented with the basic steps to build a machine learning model and followed by insights into the types of algorithms used to intelligently analyse data, identify patterns and develop realistic applications in biochemical engineering and bioprocesses. Notwithstanding, and given the scope of this review, some recent illustrative examples of MLMs in protein engineering, enzyme production, biocatalyst formulation and enzyme screening are provided, and future developments are suggested. Overall, it is envisaged that the present review will provide insights into MLMs and how these are major assets for more efficient biocatalysis.

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Xu, Xiaoman, Chao Gao, Xifeng Zhang, Bin Che, Cuiqing Ma, Jianhua Qiu, Fei Tao y Ping Xu. "Production ofN-Acetyl-d-Neuraminic Acid by Use of an Efficient Spore Surface Display System". Applied and Environmental Microbiology 77, n.º 10 (25 de marzo de 2011): 3197–201. http://dx.doi.org/10.1128/aem.00151-11.

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ABSTRACTProduction ofN-acetyl-d-neuraminic acid (Neu5Ac) via biocatalysis is traditionally conducted using isolated enzymes or whole cells. The use of isolated enzymes is restricted by the time-consuming purification process, whereas the application of whole cells is limited by the permeability barrier presented by the microbial cell membrane. In this study, a novel type of biocatalyst, Neu5Ac aldolase presented on the surface ofBacillus subtilisspores, was used for the production of Neu5Ac. Under optimal conditions, Neu5Ac at a high concentration (54.7 g liter−1) and a high yield (90.2%) was obtained under a 5-fold excess of pyruvate overN-acetyl-d-mannosamine. The novel biocatalyst system, which is able to express and immobilize the target enzyme simultaneously on the surface ofB. subtilisspores, represents a suitable alternative for value-added chemical production.

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Glaser, John A. "Biocatalyst enhancement". Clean Technologies and Environmental Policy 11, n.º 2 (junio de 2009): 147–51. http://dx.doi.org/10.1007/s10098-009-0233-4.

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Glaser, John A. "Biocatalyst greenness". Clean Technologies and Environmental Policy 16, n.º 6 (17 de julio de 2014): 991–99. http://dx.doi.org/10.1007/s10098-014-0817-5.

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Alnoch, Robson Carlos, Leandro Alves dos Santos, Janaina Marques de Almeida, Nadia Krieger y Cesar Mateo. "Recent Trends in Biomaterials for Immobilization of Lipases for Application in Non-Conventional Media". Catalysts 10, n.º 6 (20 de junio de 2020): 697. http://dx.doi.org/10.3390/catal10060697.

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The utilization of biomaterials as novel carrier materials for lipase immobilization has been investigated by many research groups over recent years. Biomaterials such as agarose, starch, chitin, chitosan, cellulose, and their derivatives have been extensively studied since they are non-toxic materials, can be obtained from a wide range of sources and are easy to modify, due to the high variety of functional groups on their surfaces. However, although many lipases have been immobilized on biomaterials and have shown potential for application in biocatalysis, special features are required when the biocatalyst is used in non-conventional media, for example, in organic solvents, which are required for most reactions in organic synthesis. In this article, we discuss the use of biomaterials for lipase immobilization, highlighting recent developments in the synthesis and functionalization of biomaterials using different methods. Examples of effective strategies designed to result in improved activity and stability and drawbacks of the different immobilization protocols are discussed. Furthermore, the versatility of different biocatalysts for the production of compounds of interest in organic synthesis is also described.

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Golikova, E. P., N. V. Lakina, O. V. Grebennikova, V. G. Matveeva y E. M. Sulman. "A study of biocatalysts based on glucose oxidase". Faraday Discussions 202 (2017): 303–14. http://dx.doi.org/10.1039/c7fd00042a.

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During this work, we studied the possibility of glucose oxidase (GOx) covalent immobilization on a modified inorganic support. A series of GOx-based biocatalysts was synthesized by crosslinking the enzyme to a surface of modified silica or alumina. Polyelectrolyte layers were used as modifiers for the silica and alumina surfaces. These layers promote tight binding of the GOx to the support. The biocatalyst’s activity and stability were studied using an oxidation reaction of d-glucose to d-gluconic acid. It was found that GOx immobilized on the modified SiO₂ using glutardialdehyde as a crosslinking agent was the most active and stable catalytic system, showing an 85% yield of gluconic acid. A study of the synthesized biocatalyst structure using FTIR spectroscopy showed that the enzyme was covalently crosslinked to the surface of an inorganic support modified with chitosan and glutardialdehyde. In the case of SiO₂, the quantity of the immobilized enzyme was higher than in the case of Al₂O₃.

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Sekuljica, Natasa, Nevena Prlainovic, Jelena Jovanovic, Andrea Stefanovic, Sanja Grbavcic, Dusan Mijin y Zorica Knezevic-Jugovic. "Immobilization of horseradish peroxidase onto kaolin by glutaraldehyde method and its application in decolorization of anthraquinone dye". Chemical Industry 70, n.º 2 (2016): 217–24. http://dx.doi.org/10.2298/hemind150220028s.

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The problem of environmental pollution day by day becomes more worrisome, primarily due to the large amounts of wastewater contaminated with various harmful organic compounds, discharged into the environment untreated or partially clean. Feasibility of use of horseradish peroxidase (Amoracia rusticana) in the synthetic dyes decolorization was approved by many researchers. Among a number of supports used for the immobilization, it was found that natural clay, kaolin has excellent features which are a precondition for obtaining biocatalysts with the excellent performances. For this reason, a horseradish peroxidase was immobilized onto kaolin using glutaraldehyde as a cross-linking agent. Obtained biocatalyst was applied in the decolorization of anthraquinone dye C. I. Acid Violet 109. Under determined optimal conditions (pH 4.0, hydrogen peroxide concentration 0.6 mM, dye concentration 30 mg L-1, temperature 24?C) around 76 % of dye decolorization was achieved. Reusability study showed that resulting biocatalyst was possible to apply four times in the desired reaction with relatively high decolorization percentage.

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Bellou, Myrto G., Michaela Patila, Renia Fotiadou, Konstantinos Spyrou, Feng Yan, Petra Rudolf, Dimitrios P. Gournis y Haralambos Stamatis. "Tyrosinase Magnetic Cross-Linked Enzyme Aggregates: Biocatalytic Study in Deep Eutectic Solvent Aqueous Solutions". Biomolecules 13, n.º 4 (3 de abril de 2023): 643. http://dx.doi.org/10.3390/biom13040643.

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In the field of biocatalysis, the implementation of sustainable processes such as enzyme immobilization or employment of environmentally friendly solvents, like Deep Eutectic Solvents (DESs) are of paramount importance. In this work, tyrosinase was extracted from fresh mushrooms and used in a carrier-free immobilization towards the preparation of both non-magnetic and magnetic cross-linked enzyme aggregates (CLEAs). The prepared biocatalyst was characterized and the biocatalytic and structural traits of free tyrosinase and tyrosinase magnetic CLEAs (mCLEAs) were evaluated in numerous DES aqueous solutions. The results showed that the nature and the concentration of the DESs used as co-solvents significantly affected the catalytic activity and stability of tyrosinase, while the immobilization enhanced the activity of the enzyme in comparison with the non-immobilized enzyme up to 3.6-fold. The biocatalyst retained the 100% of its initial activity after storage at −20 °C for 1 year and the 90% of its activity after 5 repeated cycles. Tyrosinase mCLEAs were further applied in the homogeneous modification of chitosan with caffeic acid in the presence of DES. The biocatalyst demonstrated great ability in the functionalization of chitosan with caffeic acid in the presence of 10% v/v DES [Bet:Gly (1:3)], enhancing the antioxidant activity of the films.

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da Cunha, Thiago M., Adriano A. Mendes, Daniela B. Hirata y Joelise A. F. Angelotti. "Optimized Conditions for Preparing a Heterogeneous Biocatalyst via Cross-Linked Enzyme Aggregates (CLEAs) of β-Glucosidase from Aspergillus niger". Catalysts 13, n.º 1 (28 de diciembre de 2022): 62. http://dx.doi.org/10.3390/catal13010062.

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This study mainly aims to find the optimal conditions for immobilizing a non-commercial β-glucosidase from Aspergillus niger via cross-linked enzyme aggregates (CLEAs) by investigating the effect of cross-linking agent (glutaraldehyde) concentration and soy protein isolate/enzyme ratio (or spacer/enzyme ratio) on the catalytic performance of β-glucosidase through the central composite rotatable design (CCRD). The influence of certain parameters such as pH and temperature on the hydrolytic activity of the resulting heterogeneous biocatalyst was assessed and compared with those of a soluble enzyme. The catalytic performance of both the soluble and immobilized enzyme was assessed by hydrolyzing ρ-nitrophenyl-β-D-glucopyranoside (ρ-NPG) at pH 4.5 and 50 °C. It was found that there was a maximum recovered activity of around 33% (corresponding to hydrolytic activity of 0.48 U/mL) in a spacer/enzyme ratio of 4.69 (mg/mg) using 25.5 mM glutaraldehyde. The optimal temperature and pH conditions for the soluble enzyme were 60 °C and 4.5, respectively, while those for CLEAs of β-glucosidase were between 50 and 65 °C and pH 3.5 and 4.0. These results reveal that the immobilized enzyme is more stable in a wider pH and temperature range than its soluble form. Furthermore, an improvement was observed in thermal stability after immobilization. After 150 days at 4 °C, the heterogeneous biocatalyst retained 80% of its original activity, while the soluble enzyme retained only 10%. The heterogeneous biocatalyst preparation was also characterized by TG/DTG and FT-IR analyses that confirmed the introduction of carbon chains via cross-linking. Therefore, the immobilized biocatalyst prepared in this study has improved enzyme stabilization, and it is an interesting approach to preparing heterogeneous biocatalysts for industrial applications.

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Sengupta, Sounok, Prathama Das, Samridhi Sharma, Monu Kumar Shukla, Rajesh Kumar, Rajiv Kumar Tonk, Sadanand Pandey y Deepak Kumar. "Role and Application of Biocatalysts in Cancer Drug Discovery". Catalysts 13, n.º 2 (21 de enero de 2023): 250. http://dx.doi.org/10.3390/catal13020250.

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A biocatalyst is an enzyme that speeds up or slows down the rate at which a chemical reaction occurs and speeds up certain processes by 108 times. It is used as an anticancer agent because it targets drug activation inside the tumor microenvironment while limiting damage to healthy cells. Biocatalysts have been used for the synthesis of different heterocyclic compounds and is also used in the nano drug delivery systems. The use of nano-biocatalysts for tumor-targeted delivery not only aids in tumor invasion, angiogenesis, and mutagenesis, but also provides information on the expression and activity of many markers related to the microenvironment. Iosmapinol, moclobemide, cinepazide, lysine dioxygenase, epothilone, 1-homophenylalanine, and many more are only some of the anticancer medicines that have been synthesised using biocatalysts. In this review, we have highlighted the application of biocatalysts in cancer therapies as well as the use of biocatalysts in the synthesis of drugs and drug-delivery systems in the tumor microenvironment.

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Žnidaršič-Plazl, Polona. "Let the Biocatalyst Flow". Acta Chimica Slovenica 68, n.º 1 (20 de marzo de 2021): 1–16. http://dx.doi.org/10.17344/acsi.2020.6488.

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Industrial biocatalysis has been identified as one of the key enabling technologies that, together with the transition to continuous processing, offers prospects for the development of cost-efficient manufacturing with high-quality products and low waste generation. This feature article highlights the role of miniaturized flow reactors with free enzymes and cells in the success of this endeavor with recent examples of their use in single or multiphase reactions. Microfluidics-based droplets enable ultrahigh-throughput screening and rapid biocatalytic process development. The use of unique microreactor configurations ensures highly efficient contacting of multiphase systems, resulting in process intensification and avoiding problems encountered in conventional batch processing. Further integration of downstream units offers the possibility of biocatalyst recycling, contributing to the cost-efficiency of the process. The use of environmentally friendly solvents supports effective reaction engineering, and thus paves the way for these highly selective catalysts to drive sustainable production.

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Thiele, Isabel, Heba Yehia, Niels Krausch, Mario Birkholz, Mariano Nicolas Cruz Bournazou, Azis Boing Sitanggang, Matthias Kraume, Peter Neubauer y Anke Kurreck. "Production of Modified Nucleosides in a Continuous Enzyme Membrane Reactor". International Journal of Molecular Sciences 24, n.º 7 (23 de marzo de 2023): 6081. http://dx.doi.org/10.3390/ijms24076081.

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Nucleoside analogues are important compounds for the treatment of viral infections or cancers. While (chemo-)enzymatic synthesis is a valuable alternative to traditional chemical methods, the feasibility of such processes is lowered by the high production cost of the biocatalyst. As continuous enzyme membrane reactors (EMR) allow the use of biocatalysts until their full inactivation, they offer a valuable alternative to batch enzymatic reactions with freely dissolved enzymes. In EMRs, the enzymes are retained in the reactor by a suitable membrane. Immobilization on carrier materials, and the associated losses in enzyme activity, can thus be avoided. Therefore, we validated the applicability of EMRs for the synthesis of natural and dihalogenated nucleosides, using one-pot transglycosylation reactions. Over a period of 55 days, 2′-deoxyadenosine was produced continuously, with a product yield >90%. The dihalogenated nucleoside analogues 2,6-dichloropurine-2′-deoxyribonucleoside and 6-chloro-2-fluoro-2′-deoxyribonucleoside were also produced, with high conversion, but for shorter operation times, of 14 and 5.5 days, respectively. The EMR performed with specific productivities comparable to batch reactions. However, in the EMR, 220, 40, and 9 times more product per enzymatic unit was produced, for 2′-deoxyadenosine, 2,6-dichloropurine-2′-deoxyribonucleoside, and 6-chloro-2-fluoro-2′-deoxyribonucleoside, respectively. The application of the EMR using freely dissolved enzymes, facilitates a continuous process with integrated biocatalyst separation, which reduces the overall cost of the biocatalyst and enhances the downstream processing of nucleoside production.

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Dejoma, Riccardo, Andrea Buscemi, Emilio Cutrona y Patrick Shahgaldian. "Design of a Biocatalytic Flow Reactor Based on Hierarchically Structured Monolithic Silica for Producing Galactooligosaccharides (GOSs)". CHIMIA 77, n.º 6 (28 de junio de 2023): 432–36. http://dx.doi.org/10.2533/chimia.2023.432.

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Climate change mitigation requires the development of greener chemical processes. In this context, biocatalysis is a pivotal key enabling technology. The advantages of biocatalysis include lower energy consumption levels, reduced hazardous waste production and safer processes. The possibility to carry out biocatalytic reactions under flow conditions provides the additional advantage to retain the biocatalyst and to reduce costly downstream processes. Herein, we report a method to produce galactooligosaccharides (GOSs) from a largely available feedstock (i.e. lactose from dairy production) using a flow reactor based on hierarchically structured monolithic silica. This reactor allows for fast and efficient biotransformation reaction in flow conditions.

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Gupta, Khushbu y Tejpal Singh Chundawat. "Role of Enzymes in Synthesis of Biologically Important Organic Scaffolds". Asian Journal of Chemistry 31, n.º 12 (16 de noviembre de 2019): 2698–706. http://dx.doi.org/10.14233/ajchem.2019.22205.

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Green route of biogenic synthesis of heterocyclic compounds via microbes (bacteria, fungi, virus, yeast, algae, etc.) has the potential to deliver clean manufacturing technology. The application of biocatalysts for the synthesis of novel compounds has attracted increasing attention over the past few years and consequently, high demands have been placed on the identification of new biocatalysts for organic synthesis. Enzymes play an increasingly important role as biocatalysts in the synthesis of key intermediates for the pharmaceutical and chemical industry, and new enzymatic technologies. The characteristics of biocatalyst can be tailored with protein engineering and metabolic engineering methods to meet the desired process conditions. This review discusses the synthetic application of all the six classes of enzymes which are oxidoreductase, transferase, hydrolase, lyase, isomerase and ligase. Enzymes are highly selective catalysts and their contribution to regio-, chemo- and stereoselectivity of compounds were also discussed.

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44

Glekas, Panayiotis D., Olga Martzoukou, Maria-Eleni Mastrodima, Efstathios Zarkadoulas, Dimitrios S. Kanakoglou, Dimitris Kekos, Michalis Pachnos, George Mavridis, Diomi Mamma y Dimitris G. Hatzinikolaou. "Deciphering the biodesulfurization potential of two novel <i>Rhodococcus</i> isolates from a unique Greek environment". AIMS Microbiology 8, n.º 4 (2022): 484–506. http://dx.doi.org/10.3934/microbiol.2022032.

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<abstract> <p>Sustainable biodesulfurization (BDS) processes require the use of microbial biocatalysts that display high activity against the recalcitrant heterocyclic sulfur compounds and can simultaneously withstand the harsh conditions of contact with petroleum products, inherent to any industrial biphasic BDS system. In this framework, the functional microbial BDS-related diversity in a naturally oil-exposed ecosystem, was examined through a 4,6-dimethyl-dibenzothiophene based enrichment process. Two new <italic>Rhodococcus</italic> sp. strains were isolated, which during a medium optimization process revealed a significantly enhanced BDS activity profile when compared to the model strain <italic>R. qingshengii</italic> IGTS8. In biocatalyst stability studies conducted in biphasic mode using partially hydrodesulfurized diesel under various process conditions, the new strains also presented an enhanced stability phenotype. In these studies, it was also demonstrated for all strains, that the BDS activity losses were decoupled from the overall cells' viability, in addition to the fact that the use of whole-broth biocatalyst positively affected BDS performance.</p> </abstract>

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45

Torres, Eduardo, Raunel Tinoco y Rafael Vazquez-Duhalt. "Biocatalytic oxidation of polycyclic aromatic hydrocarbons in media containing organic solvents". Water Science and Technology 36, n.º 10 (1 de noviembre de 1997): 37–44. http://dx.doi.org/10.2166/wst.1997.0354.

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Lignin peroxidase, cytochrome c and haemoglobin were tested for oxidation of polycyclic aromatic hydrocarbon (PAH) in the presence of hydrogen peroxide. The reaction mixture Contained water-miscible organic solvents in order to reduce the mass transfer limitation of hydrophobic substrates. The reaction products from all three haemoproteins were mainly quinones, suggesting the same oxidation mechanism for the three biocatalysts. The haeme prosthetic group must have located in a protein environment for it to catalyze these reactions, and only certain types of protein environment are able to induce this type of haemebased catalytic activity. The solvent hydrophobicity is a factor affecting the biocatalysis in organic media. Substrate partitioning between the active site (haeme) and the bulk solvent is the main factor of the biocatalytic behaviour in organic solvent mixtures. Site-directed mutagenesis of yeast cytochrome c significantly altered the kinetic behaviour of the protein. The Gly82;Thr 102 variant was 10 times more active and showed a catalytic efficiency 10-fold greater than the wild-type iso-1-cytochrome c. These results suggest that it is possible to design a new biocatalyst for environmental purposes.

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46

Kwon, Seok Joon, Heung-Chae Jung y Jae-Gu Pan. "Transgalactosylation in a Water-Solvent Biphasic Reaction System with β-Galactosidase Displayed on the Surfaces of Bacillus subtilis Spores". Applied and Environmental Microbiology 73, n.º 7 (22 de diciembre de 2006): 2251–56. http://dx.doi.org/10.1128/aem.01489-06.

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ABSTRACT The ever-increasing industrial demand for biocatalysis necessitates innovations in the preparation and stabilization of biocatalysts. In this study, we demonstrated that β-galactosidase (β-Gal) displayed on Bacillus spores by fusion to the spore coat proteins (CotG) may be used as a whole-cell immobilized biocatalyst for transgalactosylation in water-solvent biphasic reaction systems. The resulting spores had a specific hydrolytic activity of 5 × 103 U/g (dry weight) of spores. The β-Gal was tightly attached to the spore surface and was more stable in the presence of various organic solvents than its native form was. The thermostability of the spore-displayed enzyme was also increased, and the enzyme was further stabilized by chemically cross-linking it with glutaraldehyde. With spore-displayed β-Gal, octyl-β-d-galactopyranoside was synthesized at concentrations up to 27.7 mM (8.1 g/liter) with a conversion yield of 27.7% (wt/wt) after 24 h from 100 mM lactose and 100 mM octanol dissolved in phosphate buffer and ethyl ether, respectively. Interestingly, the spores were found to partition mainly at the interface between the water and solvent phases, and they were more available to catalysis between the two phases, as determined by light microscopy and confocal fluorescence microscopy. We propose that spore display not only offers a new and facile way to construct robust biocatalysts but also provides a novel basis for phase transfer biocatalytic processes.

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47

Grebennikova, Olga V., Anastasiya N. Mikhailova, Vladimir P. Molchanov, Aleksandrina M. Sulman, Valentin Yu Doluda y Valentina G. Matveeva. "POLYMERIC SUPPORTS FOR ENZYMES IMMOBILIZATION IN SYNTHESIS OF BIOLOGICALLY ACTIVE COMPOUNDS". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, n.º 1 (9 de diciembre de 2020): 67–72. http://dx.doi.org/10.6060/ivkkt.20216401.6223.

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The report presents the synthesis of biocatalysts based on horseradish peroxidase immobilized on commercially available polymeric supports: hyper cross-linked polystyrene MN-100 and Sepabeads EC-HA. The immobilization was carried out by covalent crosslinking of the enzyme with the support using glutaraldehyde. The optimal amount of glutaraldehyde for covalent binding of HRP was found to be 0.2 g/l. The peroxidase/MN-100 and peroxidase/Sepabeads EC-HA biocatalysts presented in the work showed good activity in the oxidation of 2-methylnaphthol to 2 methyl-1,4-naphthohydroquinone (vitamin K4). The biocatalyst based on MN-100 showed higher activity compared to the biocatalyst based on Sepabeads EC-HA, which is likely due to the different surface structure of the original polymer supports. The samples retained their activity in ten consecutive reuses. The high reusability of peroxidase/MN-100 and peroxidase/Sepabeads EC-HA is explained by the high sorption ability of commercial polymer supports MN-100 and Sepabeads EC-HA and the formation of strong covalent bonds between the enzyme and the support. The optimal conditions for the oxidation of 2-methylnaphthol to 2-methyl-1,4-naphthohydroquinone using synthesized biocatalytic systems were also selected. The temperature of 40 °C and pH 7.2 were found to be optimal for the oxidation of the proposed substrate. The presented results will undoubtedly make a positive contribution to the development of the chemical and pharmaceutical industry.

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48

Grebennikova, Olga V., Anastasiya N. Mikhailova, Vladimir P. Molchanov, Aleksandrina M. Sulman, Valentin Yu Doluda y Valentina G. Matveeva. "POLYMERIC SUPPORTS FOR ENZYMES IMMOBILIZATION IN SYNTHESIS OF BIOLOGICALLY ACTIVE COMPOUNDS". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, n.º 1 (9 de diciembre de 2020): 67–72. http://dx.doi.org/10.6060/ivkkt.20216401.6223.

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The report presents the synthesis of biocatalysts based on horseradish peroxidase immobilized on commercially available polymeric supports: hyper cross-linked polystyrene MN-100 and Sepabeads EC-HA. The immobilization was carried out by covalent crosslinking of the enzyme with the support using glutaraldehyde. The optimal amount of glutaraldehyde for covalent binding of HRP was found to be 0.2 g/l. The peroxidase/MN-100 and peroxidase/Sepabeads EC-HA biocatalysts presented in the work showed good activity in the oxidation of 2-methylnaphthol to 2 methyl-1,4-naphthohydroquinone (vitamin K4). The biocatalyst based on MN-100 showed higher activity compared to the biocatalyst based on Sepabeads EC-HA, which is likely due to the different surface structure of the original polymer supports. The samples retained their activity in ten consecutive reuses. The high reusability of peroxidase/MN-100 and peroxidase/Sepabeads EC-HA is explained by the high sorption ability of commercial polymer supports MN-100 and Sepabeads EC-HA and the formation of strong covalent bonds between the enzyme and the support. The optimal conditions for the oxidation of 2-methylnaphthol to 2-methyl-1,4-naphthohydroquinone using synthesized biocatalytic systems were also selected. The temperature of 40 °C and pH 7.2 were found to be optimal for the oxidation of the proposed substrate. The presented results will undoubtedly make a positive contribution to the development of the chemical and pharmaceutical industry.

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49

Mączka, Wanda, Daria Sołtysik, Katarzyna Wińska, Małgorzata Grabarczyk y Antoni Szumny. "Plant-Mediated Biotransformations of S(+)- and R(–)-Carvones". Applied Sciences 8, n.º 12 (13 de diciembre de 2018): 2605. http://dx.doi.org/10.3390/app8122605.

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The enzymatic system of vegetables is well known as an efficient biocatalyst in the stereoselective reduction of ketones. Therefore, we decided to use the comminuted material of several plants including five vegetables (Apium graveolens L., Beta vulgaris L., Daucus carota L., Petroselinum crispum L., and Solanum tuberosum L.) and three fruits (Malus pumila L. “Golden” and “Kortland” as well as Pyrus communis L. “Konferencja”) to obtain enantiomerically pure carveol, which is commercially unavailable. Unexpectedly, all of the used biocatalysts not only reduced the carbonyl group of (4R)-(–)-carvone and (4S)-(+)-carvone, but also reduced the double bond in the cyclohexene ring. The results revealed that (4R)-(–)-carvone was transformed into (1R, 4R)- and (1S, 4R)-dihydrocarvones, and (1R,2R,4R)-dihydrocarveol. Although the enzymatic system of the potato transformed the substrate almost completely, the %de was not the highest. Potato yielded 92%; however, when carrot was used as the biocatalyst, it was possible to obtain 17% of (1R, 4R)-(+)-dihydrocarvone with 100% diastereomeric excess. In turn, the (4S)-(+)-carvone was transformed, using the biocatalysts, into (1R, 4S)- and (1S, 4S)-dihydrocarvones and dihydrocarveols. Complete substrate conversion was observed in biotransformation when potato was used. In the experiments using apple, (1R, 4S)-dihydrocarvone with 100% diastereomeric excess was obtained. Using NMR spectroscopy, we confirmed both diastereoisomers of 4(R)-1,2-dihydrocarveols, which were unseparated in the GC condition. Finally, we proved the high usefulness of vegetables for the biotransformation of both enantiomers of carvone as well as dihydrocarvone.

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50

Scott, Charles D., Charlene A. Woodward y James E. Thompson. "Solute diffusion in biocatalyst gel beads containing biocatalysis and other additives". Enzyme and Microbial Technology 11, n.º 5 (mayo de 1989): 258–63. http://dx.doi.org/10.1016/0141-0229(89)90040-9.

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