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Shen C, Gao X, Li T, Zhang J, Gao Y, Qiu L, Zhang G. Heterologous Expression of Rhizopus Oryzae CYP509C12 Gene in Rhizopus Nigricans Enhances Reactive Oxygen Species Production and 11α-Hydroxylation Rate of 16α, 17-Epoxyprogesterone. MYCOBIOLOGY 2019; 47:301-307. [PMID: 31565466 PMCID: PMC6758629 DOI: 10.1080/12298093.2019.1630201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 02/15/2019] [Accepted: 05/30/2019] [Indexed: 06/10/2023]
Abstract
The 11α-hydroxylation of 16α, 17-epoxyprogesterone (EP) catalyzed by Rhizopus nigricans is crucial for the steroid industry. However, lower conversion rate of the biohydroxylation restricts its potential industrial application. The 11α-steroid hydroxylase CYP509C12 from R. oryzae were reported to play a crucial role in the 11α-hydroxylation in recombinant fission yeast. In the present study, the CYP509C12 of R. oryzae (RoCYP) was introduced into R. nigricans using the liposome-mediated mycelial transformation. Heterologous expression of RoCYP resulted in increased fungal growth and improved intracellular reactive oxygen species content in R. nigricans. The H2O2 levels in RoCYP transformants were approximately 2-folder that of the R. nigricans wild type (RnWT) strain, with the superoxide dismutase activities increased approximately 45% and catalase activities decreased approximately 68%. Furthermore, the 11α-hydroxylation rates of EP in RoCYP transformants (C4, C6 and C9) were 39.7%, 38.3% and 38.7%, which were 12.1%, 8.2% and 9.4% higher than the rate of the RnWT strain, respectively. This paper investigated the effect of heterologous expression of RoCYP in R. nigricans, providing an effective genetic method to construct the engineered strains for steroid industry.
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Affiliation(s)
- Chaohui Shen
- College of Life Sciences, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, China
| | - Xiyang Gao
- College of Life Sciences, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, China
| | - Tao Li
- College of Life Sciences, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, China
- Medicine and Nursing College, Sanmenxia Polytechnic Institute, Sanmenxia, China
| | - Jun Zhang
- College of Life Sciences, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, China
| | - Yuqian Gao
- College of Life Sciences, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, China
| | - Liyou Qiu
- College of Life Sciences, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, China
| | - Guang Zhang
- College of Life Sciences, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, Henan Agricultural University, Zhengzhou, China
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Enantioselective synthesis of (R)-phenylephrine by Serratia marcescens BCRC10948 cells that homologously express SM_SDR. Enzyme Microb Technol 2018; 110:14-19. [PMID: 29310851 DOI: 10.1016/j.enzmictec.2017.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 10/14/2017] [Accepted: 12/06/2017] [Indexed: 11/23/2022]
Abstract
A short-chain dehydrogenase/reductase from Serratia marcescens BCRC10948, SM_SDR, has been cloned and expressed in Escherichia coli for the bioconversion of 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) to (R)-phenylephrine[(R)-PE]. However, only 5.11mM (R)-PE was obtained from 10mM HPMAE after a 9h conversion in the previous report. To improve the biocatalytic efficiency, the homologous expression of the SM_SDR in S. marcescens BCRC10948 was achieved using the T5 promoter for expression. By using 2% glycerol as carbon source, we found that 8.00±0.15mM of (R)-PE with more than 99% enantiomeric excess was produced from 10mM HPMAE after 12h conversion at 30°C and pH 7.0. More importantly, by using 50mM HPMAE as the substrate, 23.78±0.84mM of (R)-PE was produced after a 12h conversion with the productivity and the conversion yield of 1.98mmol (R)-PE/lh and 47.50%, respectively. The recombinant S. marcescens cells could be recycled 6 times for the production of (R)-PE, and the bioconversion efficiency remained at 85% when compared to that at the first cycle. Our data indicated that a high conversion efficiency of HPMAE to (R)-PE could be achieved using S. marcescens BCRC10948 cells that homologously express the SM_SDR.
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Wedde S, Kleusch C, Bakonyi D, Gröger H. High-Throughput Feasible Screening Tool for Determining Enzyme Stabilities against Organic Solvents Directly from Crude Extracts. Chembiochem 2017; 18:2399-2403. [DOI: 10.1002/cbic.201700526] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Indexed: 01/03/2023]
Affiliation(s)
- Severin Wedde
- Chair of Organic Chemistry I; Faculty of Chemistry; Bielefeld University; Universitätsstrasse 25 33615 Bielefeld Germany
| | | | - Daniel Bakonyi
- Chair of Organic Chemistry I; Faculty of Chemistry; Bielefeld University; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Harald Gröger
- Chair of Organic Chemistry I; Faculty of Chemistry; Bielefeld University; Universitätsstrasse 25 33615 Bielefeld Germany
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Abstract
Thermodynamic principles have been applied to enzyme-catalyzed reactions since the beginning of the 1930s in an attempt to understand metabolic pathways. Currently, thermodynamics is also applied to the design and analysis of biotechnological processes. The key thermodynamic quantity is the Gibbs energy of reaction, which must be negative for a reaction to occur spontaneously. However, the application of thermodynamic feasibility studies sometimes yields positive Gibbs energies of reaction even for reactions that are known to occur spontaneously, such as glycolysis. This article reviews the application of thermodynamics in enzyme-catalyzed reactions. It summarizes the basic thermodynamic relationships used for describing the Gibbs energy of reaction and also refers to the nonuniform application of these relationships in the literature. The review summarizes state-of-the-art approaches that describe the influence of temperature, pH, electrolytes, solvents, and concentrations of reacting agents on the Gibbs energy of reaction and, therefore, on the feasibility and yield of biological reactions.
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Affiliation(s)
- Christoph Held
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, Technische Universität Dortmund, 44227 Dortmund, Germany;
| | - Gabriele Sadowski
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, Technische Universität Dortmund, 44227 Dortmund, Germany;
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Reshetilov AN, Plekhanova YV, Tarasov SE, Arlyapov VA, Kolesov VV, Gutorov MA, Gotovtsev PM, Vasilov RG. Effect of some carbon nanomaterials on ethanol oxidation by Gluconobacter oxydans bacterial cells. APPL BIOCHEM MICRO+ 2017. [DOI: 10.1134/s0003683817010161] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Korshunova IO, Pistsova ON, Kuyukina MS, Ivshina IB. The effect of organic solvents on the viability and morphofunctional properties of rhodococcus. APPL BIOCHEM MICRO+ 2016. [DOI: 10.1134/s0003683816010075] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Palmerín-Carreño DM, Rutiaga-Quiñones OM, Verde-Calvo JR, Prado-Barragán A, Huerta-Ochoa S. Whole Cell Bioconversion of (+)-valencene to (+)-nootkatone in 100 % Organic Phase using Yarrowia lipolytica 2.2ab. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2016. [DOI: 10.1515/ijcre-2016-0013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The aim of this work was to assess the whole cell bioconversion of (+)-valencene to (+)-nootkatone in 100 % organic phase (orange essential oil) using a stirred tank bioreactor. Yarrowia lipolytica 2.2ab was used to perform bioconversion experiments; 600 mL of orange essential oil was inoculated with 50 cm3 of cell paste containing 13.5 g of biomass previously permeabilized with 0.2 % (w/v) of cetyl trimethylammonium bromide (CTAB) and enriched with 2.0 mM niacin. Experiments were conducted at 200 rpm, 0.5 vvm and 30 °C. The highest (+)-nootkatone yield was ca. 773 mg L−1 after 4 days of conversion. Bioconversion percent and volumetric productivity increased to 82.3 % and 8.06 mg L−1 h−1 compared to those reported previously using a three-phase partitioning bioreactor. The absence of free water in the system did not affect the performance of Y. lipolytica 2.2ab.
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Affiliation(s)
- Dulce M. Palmerín-Carreño
- Departamento de Biotecnología, Universidad Autónoma Metropolitana, P.A. 55–535, 09340 Iztapalapa, México D.F., México
| | | | - José R. Verde-Calvo
- Departamento de Biotecnología, Universidad Autónoma Metropolitana, P.A. 55–535, 09340 Iztapalapa, México D.F., México
| | - Arely Prado-Barragán
- Departamento de Biotecnología, Universidad Autónoma Metropolitana, P.A. 55–535, 09340 Iztapalapa, México D.F., México
| | - Sergio Huerta-Ochoa
- Departamento de Biotecnología, Universidad Autónoma Metropolitana, P.A. 55–535, 09340 Iztapalapa, México D.F., México
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Effects of water content on the tetrahedral intermediate of chymotrypsin - trifluoromethylketone in polar and non-polar media: observations from molecular dynamics simulation. J Mol Model 2013; 19:2525-38. [PMID: 23455930 DOI: 10.1007/s00894-013-1807-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 02/12/2013] [Indexed: 10/27/2022]
Abstract
The work uses MD simulation to study effects of five water contents (3 %, 10 %, 20 %, 50 %, 100 % v/v) on the tetrahedral intermediate of chymotrypsin - trifluoromethyl ketone in polar acetonitrile and non-polar hexane media. The water content induced changes in the structure of the intermediate, solvent distribution and H-bonding are analyzed in the two organic media. Our results show that the changes in overall structure of the protein almost display a clear correlation with the water content in hexane media while to some extent U-shaped/bell-shaped dependence on the water content is observed in acetonitrile media with a minimum/maximum at 10-20 % water content. In contrast, the water content change in the two organic solvents does not play an observable role in the stability of catalytic hydrogen-bond network, which still exhibits high stability in all hydration levels, different from observations on the free enzyme system [Zhu L, Yang W, Meng YY, Xiao X, Guo Y, Pu X, Li M (2012) J Phys Chem B 116(10):3292-3304]. In low hydration levels, most water molecules mainly distribute near the protein surface and an increase in the water content could not fully exclude the organic solvent from the protein surface. However, the acetonitrile solvent displays a stronger ability to strip off water molecules from the protein than the hexane. In a summary, the difference in the calculated properties between the two organic solvents is almost significant in low water content (<10 %) and become to be small with increasing water content. In addition, some structural properties at 10 ~ 20 % v/v hydration zone, to large extent, approach to those in aqueous solution.
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Zhang XY, Peng Y, Su ZR, Chen QH, Ruan H, He GQ. Optimization of biotransformation from phytosterol to androstenedione by a mutant Mycobacterium neoaurum ZJUVN-08. J Zhejiang Univ Sci B 2013; 14:132-43. [PMID: 23365012 DOI: 10.1631/jzus.b1200067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Biotransformation of phytosterol (PS) by a newly isolated mutant Mycobacterium neoaurum ZJUVN-08 to produce androstenedione has been investigated in this paper. The parameters of the biotransformation process were optimized using fractional factorial design and response surface methodology. Androstenedione was the sole product in the fermentation broth catalyzed by the mutant M. neoaurum ZJUVN-08 strain. Results showed that molar ratio of hydroxypropyl-β-cyclodextrin (HP-β-CD) to PS and substrate concentrations were the two most significant factors affecting androstenedione production. By analyzing the statistical model of three-dimensional surface plot, the optimal process conditions were observed at 0.1 g/L inducer, pH 7.0, molar ratio of HP-β-CD to PS 1.92:1, 8.98 g/L PS, and at 120 h of incubation time. Under these conditions, the maximum androstenedione yield was 5.96 g/L and nearly the same with the non-optimized (5.99 g/L), while the maximum PS conversion rate was 94.69% which increased by 10.66% compared with the non-optimized (84.03%). The predicted optimum conditions from the mathematical model were in agreement with the verification experimental results. It is considered that response surface methodology was a powerful and efficient method to optimize the parameters of PS biotransformation process.
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Affiliation(s)
- Xiao-yan Zhang
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
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Bhattacharyya MS, Singh A, Banerjee UC. Asymmetric reduction of a ketone by wet and lyophilized cells of Geotrichum candidum in organic solvents. N Biotechnol 2012; 29:359-64. [DOI: 10.1016/j.nbt.2011.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 07/18/2011] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
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11
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Fragnelli MC, Hoyos P, Romano D, Gandolfi R, Alcántara AR, Molinari F. Enantioselective reduction and deracemisation using the non-conventional yeast Pichia glucozyma in water/organic solvent biphasic systems: preparation of (S)-1,2-diaryl-2-hydroxyethanones (benzoins). Tetrahedron 2012. [DOI: 10.1016/j.tet.2011.11.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Rosche B, Li XZ, Hauer B, Schmid A, Buehler K. Microbial biofilms: a concept for industrial catalysis? Trends Biotechnol 2009; 27:636-43. [PMID: 19783314 DOI: 10.1016/j.tibtech.2009.08.001] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 08/13/2009] [Accepted: 08/14/2009] [Indexed: 11/18/2022]
Abstract
Biofilm reactors have long been commercially used in the treatment of wastewater and off-gas. New opportunities are arising with the rapid expansion of our understanding of biofilm biology over the last few years. Biofilms have great potential as industrial workhorses for the sustainable production of chemicals because of their inherent characteristics of self-immobilization, high resistance to reactants and long-term activity, which all facilitate continuous processing. A variety of biofilm reactor configurations have been explored for productive catalysis and some reactors have been operated continuously for months. Sectors that might particularly benefit from this biofilm approach include synthetic chemistry (ranging from specialty to bulk chemicals), bioenergy, biologics and the food industry.
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Affiliation(s)
- Bettina Rosche
- The University of New South Wales, School of Biotechnology and Biomolecular Sciences, Sydney, NSW 2052, Australia.
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15
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Arabi H, Yazdi MT, Faramarzi MA. Application of organic mono-phase and organic–aqueous two-liquid-phase systems in microalgal conversion of androst-4-en-3,17-dione byNostoc muscorum. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420902890018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Whole cell microbial transformation in cloud point system. J Ind Microbiol Biotechnol 2008; 35:645-56. [DOI: 10.1007/s10295-008-0345-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Revised: 02/15/2008] [Accepted: 03/20/2008] [Indexed: 10/22/2022]
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17
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Simon L, Kotormán M, Szabó A, Nemcsók J, Laczkó I. The effects of organic solvent/water mixtures on the structure and catalytic activity of porcine pepsin. Process Biochem 2007. [DOI: 10.1016/j.procbio.2007.01.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Application of ionic liquids in enzymic resolution by hydrolysis of cycloalkyl acetates. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.tetasy.2006.10.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Wang Z, Zhao F, Chen D, Li D. Cloud point system as a tool to improve the efficiency of biotransformation. Enzyme Microb Technol 2005. [DOI: 10.1016/j.enzmictec.2004.12.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Wang Z, Zhao F, Hao X, Chen D, Li D. Microbial transformation of hydrophobic compound in cloud point system. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcatb.2003.11.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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22
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Orlich B, Schomäcker R. Enzyme catalysis in reverse micelles. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2002; 75:185-208. [PMID: 11783840 DOI: 10.1007/3-540-44604-4_6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Water in oil microemulsions with reverse micelles provide an interesting alternative to normal organic solvents in enzyme catalysis with hydrophobic substrates. Reverse micelles are useful microreactors because they can host proteins like enzymes. Catalytic reactions with water insoluble substrates can occur at the large internal water-oil interface inside the microemulsion. The activity and stability of biomolecules can be controlled, mainly by the concentration of water in these media. With the exact knowledge of the phase behaviour and the corresponding activity of enzymes the application of these media can lead to favourable effects compared to aqueous systems, like hyperactivity or increased stability of the enzymes.
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Simon LM, Kotormán M, Garab G, Laczkó I. Structure and activity of alpha-chymotrypsin and trypsin in aqueous organic media. Biochem Biophys Res Commun 2001; 280:1367-71. [PMID: 11162681 DOI: 10.1006/bbrc.2001.4282] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of different concentrations (20-95%) of organic solvents (ethanol, 1,4-dioxane and acetonitrile) were studied on alpha-chymotrypsin and trypsin from bovine pancreas. The changes in secondary structure were followed by CD measurements, and the apparent Michaelis constants (KMapp) and the stabilities of the enzymes were determined. Significant alterations in the CD spectra were found for both enzymes at the different organic solvent concentrations. The apparent KM values of trypsin and alpha-chymotrypsin decreased as the low solvent concentrations were elevated, but then increased in the presence of higher organic solvent concentrations. The stabilities of the enzymes changed on increase of the organic solvent concentration; trypsin exhibited a higher stability than that of alpha-chymotrypsin in all organic solvents. These results show that at an organic solvent content of 95% the manifestation of an enzyme activity similar to that measured in water can be attributed to the similar compositions of the secondary structural elements.
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Affiliation(s)
- L M Simon
- Department of Biochemistry, Faculty of Science, University of Szeged, Szeged, Hungary.
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Orlich B, Schomäcker R. Candida Rugosa lipase reactions in nonionic w/o-microemulsion with a technical surfactant. Enzyme Microb Technol 2001; 28:42-48. [PMID: 11118597 DOI: 10.1016/s0141-0229(00)00268-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In enzyme catalysis there is a great interest in finding suitable organic media for less water soluble substrates in order to increase the substrate concentration and therefore the reaction rates. These requirements are fulfilled by using w/o-microemulsions as reaction media. The influences of pH, temperature, water concentration and the kinetic parameters of Candida Rugosa Lipase in a nonionic w/o-microemulsion with a surfactant of technical grade, Marlipal O13-60, are presented. In an example the enantiospecific esterification of racemic menthol with propionic anhydride using this nonionic microemulsion likely to be affordable in large scale applications is shown. For a continuous process an ultrafiltration unit is attached to a reactor within a loop. In this way, the reverse micelles containing the enzymes can be separated from the oil, containing the product, and reused afterwards.
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Affiliation(s)
- B Orlich
- Institut für Technische Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623, Berlin, Germany
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Production of flavour ketones in aqueous-organic two-phase systems by using free and microencapsulated fungal spores as biocatalysts. Enzyme Microb Technol 2000; 26:235-242. [PMID: 10689083 DOI: 10.1016/s0141-0229(99)00140-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The formation of 2-alkanones by free and microencapsulated P. roquefortii spores in an aqueous-organic two-phase system was investigated by using substrates supplied as a solution in decane. It was shown that the spores remained catalytically active after entrapment within permeable polyamide microcapsules and readily catalyzed the formation of 2-pentanone, 2-heptanone, and 2-undecanone from short-chain alkyl esters of hexanoic, octanoic, and lauric acid, respectively, with the rate of reaction being markedly dependent on the type and concentration of the ester substrate used. In general, the optimal concentration of the esters in decane was found to be much higher than that of the respective fatty acid substrates and, in the case of alkyl dodecanoates, the biotransformation could be carried out efficiently even in the absence of added solvent. Further analysis revealed a significant difference in the reaction rates observed with free and microencapsulated spores at 0.5 but not at 3.0 M methyl dodecanoate, suggesting that at high substrate concentrations the biotransformation was no longer limited by mass transfer.
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Abstract
In enzyme catalysis there is great interest in finding suitable organic media for less water-soluble substrates in order to increase the substrate concentration and, therefore, the reaction rates. These requirements are fulfilled by using microemulsions as reaction media. In this study w/o-microemulsions were used to investigate the kinetics of the reduction of 2-Heptanone to S-2-Heptanol, catalyzed by alcohol dehydrogenase. The required cofactor NADH for this reduction is regenerated by a second enzyme, formate dehydrogenase. The influences of pH, temperature, and the kinetic parameters of the enzymes are presented. It is demonstrated that in microemulsions the reaction rate of ADH is increased up to 12 times compared to water.
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Affiliation(s)
- B Orlich
- Institute of Technical Chemistry, Technical University Berlin, Strasse des 17. Juni 135, 10623 Berlin, Federal Republic of Germany
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28
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Stability of free and immobilized Mycobacterium sp. cells in aqueous and organic media. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s0921-0423(98)80093-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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