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Soni S, Sathe SS, Sheth RR, Tiwari P, Vadgama RKN, Odaneth AA, Lali AM, Chandrayan SK. N-terminal domain replacement changes an archaeal monoacylglycerol lipase into a triacylglycerol lipase. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:110. [PMID: 31080517 PMCID: PMC6501381 DOI: 10.1186/s13068-019-1452-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 04/25/2019] [Indexed: 05/09/2023]
Abstract
BACKGROUND Lipolytic enzymes of hyperthermophilic archaea generally prefer small carbon chain fatty acid esters (C2-C12) and are categorized as esterases. However, a few have shown activity with long-chain fatty acid esters, but none of them have been classified as a true lipase except a lipolytic enzyme AFL from Archaeglobus fulgidus. Thus, our main objective is to engineer an archaeal esterase into a true thermostable lipase for industrial applications. Lipases which hydrolyze long-chain fatty acid esters display an interfacial activation mediated by the lid domain which lies over active site and switches to open conformation at the oil-water interface. Lid domains modulate enzyme activities, substrate specificities, and stabilities which have been shown by protein engineering and mutational analyses. Here, we report engineering of an uncharacterized monoacylglycerol lipase (TON-LPL) from an archaeon Thermococcus onnurineus (strain NA1) into a triacylglycerol lipase (rc-TGL) by replacing its 61 N-terminus amino acid residues with 118 residues carrying lid domain of a thermophilic fungal lipase-Thermomyces lanuginosus (TLIP). RESULTS TON-LPL and rc-TGL were cloned and overexpressed in E. coli, and the proteins were purified by Ni-NTA affinity chromatography for biochemical studies. Both enzymes were capable of hydrolyzing various monoglycerides and shared the same optimum pH of 7.0. However, rc-TGL showed a significant decrease of 10 °C in its optimum temperature (Topt). The far UV-CD spectrums were consistent with a well-folded α/β-hydrolase fold for both proteins, but gel filtration chromatography revealed a change in quaternary structure from trimer (TON-LPL) to monomer (rc-TGL). Seemingly, the difference in the oligomeric state of rc-TGL may be linked to a decrease in temperature optimum. Nonetheless, rc-TGL hydrolyzed triglycerides and castor oil, while TON-LPL was not active with these substrates. CONCLUSIONS Here, we have confirmed the predicted esterase activity of TON-LPL and also performed the lid engineering on TON-LPL which effectively expanded its substrate specificity from monoglycerides to triglycerides. This approach provides a way to engineer other hyperthermophilic esterases into industrially suitable lipases by employing N-terminal domain replacement. The immobilized preparation of rc-TGL has shown significant activity with castor oil and has a potential application in castor oil biorefinery to obtain value-added chemicals.
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Affiliation(s)
- Surabhi Soni
- DBT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
| | - Sneha S. Sathe
- DBT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
| | - Rutuja R. Sheth
- DBT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
| | - Prince Tiwari
- IISER Mohali, Knowledge City, Sector 81, Manauli PO, Sahibzada Ajit Singh Nagar, Punjab 140306 India
| | - Rajesh-Kumar N. Vadgama
- DBT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
| | - Annamma Anil Odaneth
- DBT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
| | - Arvind M. Lali
- DBT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
- Department of Chemical Engineering, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
| | - Sanjeev K. Chandrayan
- DBT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga East, Mumbai, Maharashtra 400019 India
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Varejão N, De-Andrade RA, Almeida RV, Anobom CD, Foguel D, Reverter D. Structural Mechanism for the Temperature-Dependent Activation of the Hyperthermophilic Pf2001 Esterase. Structure 2018; 26:199-208.e3. [PMID: 29307486 DOI: 10.1016/j.str.2017.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 09/28/2017] [Accepted: 12/06/2017] [Indexed: 10/18/2022]
Abstract
Lipases and esterases constitute a group of enzymes that catalyze the hydrolysis or synthesis of ester bonds. A major biotechnological interest corresponds to thermophilic esterases, due to their intrinsic stability at high temperatures. The Pf2001 esterase from Pyrococcus furiosus reaches its optimal activity between 70°C and 80°C. The crystal structure of the Pf2001 esterase shows two different conformations: monomer and dimer. The structures reveal important rearrangements in the "cap" subdomain between monomer and dimer, by the formation of an extensive intertwined helical interface. Moreover, the dimer interface is essential for the formation of the hydrophobic channel for substrate selectivity, as confirmed by mutagenesis and kinetic analysis. We also provide evidence for dimer formation at high temperatures, a process that correlates with its enzymatic activation. Thus, we propose a temperature-dependent activation mechanism of the Pf2001 esterase via dimerization that is necessary for the substrate channel formation in the active-site cleft.
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Affiliation(s)
- Nathalia Varejão
- Institut de Biotecnologia i de Biomedicina and Departamento de Bioquimica i Biologia Molecular, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain; Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Biologia Estrutural, Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, RJ, Brazil
| | - Rafael A De-Andrade
- Instituto de Química, Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio de Janeiro, 21941-909 Rio de Janeiro, Brazil
| | - Rodrigo V Almeida
- Instituto de Química, Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio de Janeiro, 21941-909 Rio de Janeiro, Brazil
| | - Cristiane D Anobom
- Instituto de Química, Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio de Janeiro, 21941-909 Rio de Janeiro, Brazil
| | - Debora Foguel
- Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Biologia Estrutural, Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, RJ, Brazil.
| | - David Reverter
- Institut de Biotecnologia i de Biomedicina and Departamento de Bioquimica i Biologia Molecular, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain.
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3
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Zarafeta D, Szabo Z, Moschidi D, Phan H, Chrysina ED, Peng X, Ingham CJ, Kolisis FN, Skretas G. EstDZ3: A New Esterolytic Enzyme Exhibiting Remarkable Thermostability. Front Microbiol 2016; 7:1779. [PMID: 27899916 PMCID: PMC5110521 DOI: 10.3389/fmicb.2016.01779] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/24/2016] [Indexed: 11/25/2022] Open
Abstract
Lipolytic enzymes that retain high levels of catalytic activity when exposed to a variety of denaturing conditions are of high importance for a number of biotechnological applications. In this study, we aimed to identify new lipolytic enzymes, which are highly resistant to prolonged exposure to elevated temperatures. To achieve this, we searched for genes encoding for such proteins in the genomes of a microbial consortium residing in a hot spring located in China. After performing functional genomic screening on a bacterium of the genus Dictyoglomus, which was isolated from this hot spring following in situ enrichment, we identified a new esterolytic enzyme, termed EstDZ3. Detailed biochemical characterization of the recombinant enzyme, revealed that it constitutes a slightly alkalophilic and highly active esterase against esters of fatty acids with short to medium chain lengths. Importantly, EstDZ3 exhibits remarkable thermostability, as it retains high levels of catalytic activity after exposure to temperatures as high as 95°C for several hours. Furthermore, it exhibits very good stability against exposure to high concentrations of a variety of organic solvents. Interestingly, EstDZ3 was found to have very little similarity to previously characterized esterolytic enzymes. Computational modeling of the three-dimensional structure of this new enzyme predicted that it exhibits a typical α/β hydrolase fold that seems to include a “subdomain insertion”, which is similar to the one present in its closest homolog of known function and structure, the cinnamoyl esterase Lj0536 from Lactobacillus johnsonii. As it was found in the case of Lj0536, this structural feature is expected to be an important determinant of the catalytic properties of EstDZ3. The high levels of esterolytic activity of EstDZ3, combined with its remarkable thermostability and good stability against a range of organic solvents and other denaturing agents, render this new enzyme a candidate biocatalyst for high-temperature biotechnological applications.
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Affiliation(s)
- Dimitra Zarafeta
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research FoundationAthens, Greece; Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of AthensAthens, Greece
| | | | - Danai Moschidi
- Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens Athens, Greece
| | - Hien Phan
- Danish Archaea Centre, Department of Biology, Copenhagen University Copenhagen, Denmark
| | - Evangelia D Chrysina
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation Athens, Greece
| | - Xu Peng
- Danish Archaea Centre, Department of Biology, Copenhagen University Copenhagen, Denmark
| | | | - Fragiskos N Kolisis
- Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens Athens, Greece
| | - Georgios Skretas
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation Athens, Greece
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Mandelli F, Gonçalves TA, Gandin CA, Oliveira ACP, Oliveira Neto M, Squina FM. Characterization and Low-Resolution Structure of an Extremely Thermostable Esterase of Potential Biotechnological Interest from Pyrococcus furiosus. Mol Biotechnol 2016; 58:757-766. [DOI: 10.1007/s12033-016-9975-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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5
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Choi YH, Park YJ, Yoon SJ, Lee HB. Purification and characterization of a new inducible thermostable extracellular lipolytic enzyme from the thermoacidophilic archaeon Sulfolobus solfataricus P1. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2015.11.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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6
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Zhu Y, Zheng W, Ni H, Liu H, Xiao A, Cai H. Molecular cloning and characterization of a new and highly thermostable esterase from Geobacillus sp. JM6. J Basic Microbiol 2015; 55:1219-31. [PMID: 26175347 DOI: 10.1002/jobm.201500081] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/20/2015] [Indexed: 11/09/2022]
Abstract
A new lipolytic enzyme gene was cloned from a thermophile Geobacillus sp. JM6. The gene contained 750 bp and encoded a 249-amino acid protein. The recombinant enzyme was expressed and purified from Escherichia coli BL21 (DE3) with a molecular mass of 33.6 kDa. Enzyme assays using p-nitrophenyl esters with different acyl chain lengths as the substrates confirmed its esterase activity, yielding the highest activity with p-nitrophenyl butyrate. When p-nitrophenyl butyrate was used as a substrate, the optimum reaction temperature and pH for the enzyme were 60 °C and pH 7.5, respectively. Geobacillus sp. JM6 esterase showed excellent thermostability with 68% residual activity after incubation at 100 °C for 18 h. A theoretical structural model of strain JM6 esterase was developed with a monoacylglycerol lipase from Bacillus sp. H-257 as a template. The predicted core structure exhibits an α/β hydrolase fold, and a putative catalytic triad (Ser97, Asp196, and His226) was identified. Inhibition assays with PMSF indicated that serine residue is involved in the catalytic activity of strain JM6 esterase. The recombinant esterase showed a relatively good tolerance to the detected detergents and denaturants, such as SDS, Chaps, Tween 20, Tween 80, Triton X-100, sodium deoxycholate, urea, and guanidine hydrochloride.
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Affiliation(s)
- Yanbing Zhu
- College of Food and Biological Engineering, Jimei University, Xiamen, China.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, China.,Research Center of Food Biotechnology of Xiamen City, Xiamen, China
| | - Wenguang Zheng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Hui Ni
- College of Food and Biological Engineering, Jimei University, Xiamen, China.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, China.,Research Center of Food Biotechnology of Xiamen City, Xiamen, China
| | - Han Liu
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - Anfeng Xiao
- College of Food and Biological Engineering, Jimei University, Xiamen, China.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, China.,Research Center of Food Biotechnology of Xiamen City, Xiamen, China
| | - Huinong Cai
- College of Food and Biological Engineering, Jimei University, Xiamen, China.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, China.,Research Center of Food Biotechnology of Xiamen City, Xiamen, China
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7
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A first continuous 4-aminoantipyrine (4-AAP)-based screening system for directed esterase evolution. Appl Microbiol Biotechnol 2015; 99:5237-46. [DOI: 10.1007/s00253-015-6612-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 04/02/2015] [Accepted: 04/15/2015] [Indexed: 10/23/2022]
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8
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Marine extremophiles: a source of hydrolases for biotechnological applications. Mar Drugs 2015; 13:1925-65. [PMID: 25854643 PMCID: PMC4413194 DOI: 10.3390/md13041925] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 03/22/2015] [Accepted: 03/25/2015] [Indexed: 12/26/2022] Open
Abstract
The marine environment covers almost three quarters of the planet and is where evolution took its first steps. Extremophile microorganisms are found in several extreme marine environments, such as hydrothermal vents, hot springs, salty lakes and deep-sea floors. The ability of these microorganisms to support extremes of temperature, salinity and pressure demonstrates their great potential for biotechnological processes. Hydrolases including amylases, cellulases, peptidases and lipases from hyperthermophiles, psychrophiles, halophiles and piezophiles have been investigated for these reasons. Extremozymes are adapted to work in harsh physical-chemical conditions and their use in various industrial applications such as the biofuel, pharmaceutical, fine chemicals and food industries has increased. The understanding of the specific factors that confer the ability to withstand extreme habitats on such enzymes has become a priority for their biotechnological use. The most studied marine extremophiles are prokaryotes and in this review, we present the most studied archaea and bacteria extremophiles and their hydrolases, and discuss their use for industrial applications.
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9
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Nam JK, Park YJ, Lee HB. Cloning, expression, purification, and characterization of a thermostable esterase from the archaeon Sulfolobus solfataricus P1. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcatb.2013.05.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Zhu Y, Li J, Cai H, Ni H, Xiao A, Hou L. Characterization of a new and thermostable esterase from a metagenomic library. Microbiol Res 2013; 168:589-97. [PMID: 23684391 DOI: 10.1016/j.micres.2013.04.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/30/2013] [Accepted: 04/02/2013] [Indexed: 11/30/2022]
Abstract
A new gene encoding an esterase (designated as EstEP16) was identified from a metagenomic library prepared from a sediment sample collected from a deep-sea hydrothermal field in east Pacific. The open reading frame of this gene encoded 249 amino acid residues. It was cloned, overexpressed in Escherichia coli, and the recombinant protein was purified to homogeneity. The monomeric EstEP16 presented a molecular mass of 51.7 kDa. Enzyme assays using p-nitrophenyl esters with different acyl chain lengths as the substrates confirmed its esterase activity, yielding highest specific activity with p-nitrophenyl acetate. When p-nitrophenyl butyrate was used as a substrate, recombinant EstEP16 exhibited highest activity at pH 8.0 and 60°C. The recombinant enzyme retained about 80% residual activity after incubation at 90°C for 6 h, which indicated that EstEP16 was thermostable. Homology modeling of EstEP16 was developed with the monoacylglycerol lipase from Bacillus sp. H-257 as a template. The structure showed an α/β-hydrolase fold and indicated the presence of a typical catalytic triad. The activity of EstEP16 was inhibited by addition of phenylmethylsulfonyl fluoride, indicating that it contains serine residue, which plays a key role in the catalytic mechanism.
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Affiliation(s)
- Yanbing Zhu
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, People's Republic of China
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11
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Ozcan B, Ozyilmaz G, Cihan A, Cokmus C, Caliskan M. Phylogenetic analysis and characterization of lipolytic activity of halophilic archaeal isolates. Microbiology (Reading) 2012. [DOI: 10.1134/s0026261712020105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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12
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Lipases and esterases from extremophiles: overview and case example of the production and purification of an esterase from Thermus thermophilus HB27. Methods Mol Biol 2012; 861:239-66. [PMID: 22426723 DOI: 10.1007/978-1-61779-600-5_15] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Extremophiles are organisms that have evolved to exist in a variety of extreme environments. They fall into a number of different classes that include thermophiles, halophiles, acidophiles, alkalophiles, psychrophiles, and barophiles (piezophiles). Extremophiles have the potential to produce uniquely valuable biocatalysts that function under conditions in which usually the enzymes of their nonextremophilic counterparts could not. Among novel enzymes isolated from extremophilic microorganisms, hydrolases, and particularly lipases and esterases are experiencing a growing demand. Lipases (EC 3.1.1.3) and esterases (EC 3.1.1.1) catalyze the cleavage of ester bounds in aqueous media and the reverse reaction in organic solvents. Both lipolytic enzymes have relevant applications in food, dairy, detergent, biofuel, and pharmaceutical industries. Here, we summarize the properties of lipases and esterases from the main extremophile groups: thermophiles and hyperthermophiles, psychrophiles, halophiles, alkalophiles/acidophiles, and solvent-resistant microorganisms.We report the biomass and lipolytic activity production by Thermus thermophilus HB27 in 5-L stirred-tank bioreactor at 70°C. Suitability of thermal spring water for culture media formulation is shown. In addition, a protocol to isolate and purify a cell-bound esterase from this microorganism is described.
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Sivaramakrishnan R, Muthukumar K. Isolation of Thermo-stable and Solvent-Tolerant Bacillus sp. Lipase for the Production of Biodiesel. Appl Biochem Biotechnol 2011; 166:1095-111. [DOI: 10.1007/s12010-011-9497-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 12/11/2011] [Indexed: 10/14/2022]
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14
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Rao L, Xue Y, Zhou C, Tao J, Li G, Lu JR, Ma Y. A thermostable esterase from Thermoanaerobacter tengcongensis opening up a new family of bacterial lipolytic enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:1695-702. [DOI: 10.1016/j.bbapap.2011.08.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 08/22/2011] [Accepted: 08/24/2011] [Indexed: 11/25/2022]
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Schmidt M, Larsen DM, Stougaard P. A lipase with broad temperature range from an alkaliphilic gamma-proteobacterium isolated in Greenland. ENVIRONMENTAL TECHNOLOGY 2010; 31:1091-1100. [PMID: 20718291 DOI: 10.1080/09593331003770289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A gamma-proteobacterium related to the genera Alteromonadales and Pseudomonadales, isolated from a cold and alkaline environment in Greenland, has been shown to produce a lipase active between 5 degrees C and 80 degrees C, with optimal activity at 55 degrees C and pH 8. PCR-based screening of genomic DNA from the isolated bacterium, followed by genome walking, resulted in two complete open reading frames, which were predicted to encode a lipase and its helper protein, a lipase foldase. The amino acid sequence derived for the lipase showed resemblance to lipases from Pseudomonas, Rhodoferax, Aeromonas and Vibrio. The two genes were cloned into different expression systems in E. coli with or without a putative secretion sequence, but despite the fact that both recombinant lipase and lipase foldase were observed on SDS-PAGE, no recombinant lipase activity was detected. Attempts to refold the recombinant lipase in vitro using a purified lipase foldase remained unsuccessful.
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Affiliation(s)
- Mariane Schmidt
- Department of Agriculture and Ecology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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Yu S, Zheng B, Zhao X, Feng Y. Gene cloning and characterization of a novel thermophilic esterase from Fervidobacterium nodosum Rt17-B1. Acta Biochim Biophys Sin (Shanghai) 2010; 42:288-95. [PMID: 20383468 DOI: 10.1093/abbs/gmq020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A bioinformatic screening of the genome of the thermophilic bacterium Fervidobacterium nodosum Rt17-B1 for esterhydrolyzing enzymes revealed a putative bacterial esterase (FNE) encoded by Fond_1301 with typical GDSL family motifs. To confirm its putative esterase function, the FNE gene was cloned, functionally expressed in Escherichia coli, and purified to homogeneity. Recombinant FNE exhibited the highest esterase activity of 14,000 U/mg with p-nitrophenyl acetate (pNPC(2)) as substrate. The catalytic efficiency (k(cat)/K(m)) toward p-nitrophenyl acetate (C(2)) was approximately 120-fold higher than toward p-nitrophenyl butyrate (C(4)). No significant esterase activity was observed for the substrates with a chain length > or =C(8). The monomeric enzyme has a molecular mass of 27.5 kDa and exhibits optimal activity around 75 degrees C, at pH 8.5. Its thermostability is relatively high with a half-life of 80 min at 70 degrees C, but less stable compared with some other hyperthermophilic esterases. A structural model was constructed using acetylesterase from Aspergillus aculeatus as a template. The structure showed an alpha/beta-hydrolase fold and indicated the presence of a typical catalytic triad consisting of a serine, aspartate, and histidine, which was verified by site-directed mutagenesis. Sequence analysis showed that FNE was only distantly related to other esterases. A comparison of the conserved motifs shared with GDSL proteins revealed that FNE could be grouped into GDSL family and was further classified as SGNH hydrolase.
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Levisson M, van der Oost J, Kengen SWM. Carboxylic ester hydrolases from hyperthermophiles. Extremophiles 2009; 13:567-81. [PMID: 19544040 PMCID: PMC2706381 DOI: 10.1007/s00792-009-0260-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 06/04/2009] [Indexed: 11/28/2022]
Abstract
Carboxylic ester hydrolyzing enzymes constitute a large group of enzymes that are able to catalyze the hydrolysis, synthesis or transesterification of an ester bond. They can be found in all three domains of life, including the group of hyperthermophilic bacteria and archaea. Esterases from the latter group often exhibit a high intrinsic stability, which makes them of interest them for various biotechnological applications. In this review, we aim to give an overview of all characterized carboxylic ester hydrolases from hyperthermophilic microorganisms and provide details on their substrate specificity, kinetics, optimal catalytic conditions, and stability. Approaches for the discovery of new carboxylic ester hydrolases are described. Special attention is given to the currently characterized hyperthermophilic enzymes with respect to their biochemical properties, 3D structure, and classification.
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Affiliation(s)
- Mark Levisson
- Department of Agrotechnology and Food Sciences, Wageningen University, The Netherlands.
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18
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Characterization of extracellular esterase and lipase activities from five halophilic archaeal strains. J Ind Microbiol Biotechnol 2008; 36:105-10. [DOI: 10.1007/s10295-008-0477-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2008] [Accepted: 09/16/2008] [Indexed: 10/21/2022]
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Salameh M, Wiegel J. Lipases from extremophiles and potential for industrial applications. ADVANCES IN APPLIED MICROBIOLOGY 2007; 61:253-83. [PMID: 17448792 DOI: 10.1016/s0065-2164(06)61007-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Moh'd Salameh
- Microbiology Department, University of Georgia, Athens, GA 30602, USA
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Unsworth LD, van der Oost J, Koutsopoulos S. Hyperthermophilic enzymes − stability, activity and implementation strategies for high temperature applications. FEBS J 2007; 274:4044-56. [PMID: 17683334 DOI: 10.1111/j.1742-4658.2007.05954.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Current theories agree that there appears to be no unique feature responsible for the remarkable heat stability properties of hyperthermostable proteins. A concerted action of structural, dynamic and other physicochemical attributes are utilized to ensure the delicate balance between stability and functionality of proteins at high temperatures. We have thoroughly screened the literature for hyperthermostable enzymes with optimal temperatures exceeding 100 degrees C that can potentially be employed in multiple biotechnological and industrial applications and to substitute traditionally used, high-cost engineered mesophilic/thermophilic enzymes that operate at lower temperatures. Furthermore, we discuss general methods of enzyme immobilization and suggest specific strategies to improve thermal stability, activity and durability of hyperthermophilic enzymes.
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Affiliation(s)
- Larry D Unsworth
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada
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Levisson M, van der Oost J, Kengen SWM. Characterization and structural modeling of a new type of thermostable esterase from Thermotoga maritima. FEBS J 2007; 274:2832-42. [PMID: 17466017 DOI: 10.1111/j.1742-4658.2007.05817.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A bioinformatic screening of the genome of the hyperthermophilic bacterium Thermotoga maritima for ester-hydrolyzing enzymes revealed a protein with typical esterase motifs, though annotated as a hypothetical protein. To confirm its putative esterase function the gene (estD) was cloned, functionally expressed in Escherichia coli and purified to homogeneity. Recombinant EstD was found to exhibit significant esterase activity with a preference for short acyl chain esters (C4-C8). The monomeric enzyme has a molecular mass of 44.5 kDa and optimal activity around 95 degrees C and at pH 7. Its thermostability is relatively high with a half-life of 1 h at 100 degrees C, but less stable compared to some other hyperthermophilic esterases. A structural model was constructed with the carboxylesterase Est30 from Geobacillus stearothermophilus as a template. The model covered most of the C-terminal part of EstD. The structure showed an alpha/beta-hydrolase fold and indicated the presence of a typical catalytic triad consisting of a serine, aspartate and histidine, which was verified by site-directed mutagenesis and inhibition studies. Phylogenetic analysis showed that EstD is only distantly related to other esterases. A comparison of the active site pentapeptide motifs revealed that EstD should be grouped into a new family of esterases (Family 10). EstD is the first characterized member of this family.
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Affiliation(s)
- Mark Levisson
- Laboratory of Microbiology, Wageningen University, Hesselink van Suchtelenweg 4, 6703 GT Wageningen, The Netherlands.
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22
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Cloning, expression, partial characterization and structural modeling of a novel esterase from Pyrococcus furiosus. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2006.02.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Boutaiba S, Bhatnagar T, Hacene H, Mitchell D, Baratti J. Preliminary characterisation of a lipolytic activity from an extremely halophilic archaeon, Natronococcus sp. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcatb.2006.03.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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24
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Egorova K, Antranikian G. Industrial relevance of thermophilic Archaea. Curr Opin Microbiol 2005; 8:649-55. [PMID: 16257257 DOI: 10.1016/j.mib.2005.10.015] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 10/13/2005] [Indexed: 11/30/2022]
Abstract
The dramatic increase of newly isolated extremophilic microorganisms, analysis of their genomes and investigations of their enzymes by academic and industrial laboratories demonstrate the great potential of extremophiles in industrial (white) biotechnology. Enzymes derived from extremophiles (extremozymes) are superior to the traditional catalysts because they can perform industrial processes even under harsh conditions, under which conventional proteins are completely denatured. In particular, enzymes from thermophilic and hyperthermophilic Archaea have industrial relevance. Despite intensive investigations, our knowledge of the structure-function relationships of their enzymes is still limited. Information concerning the molecular properties of their enzymes and genes has to be obtained to be able to understand the mechanisms that are responsible for catalytic activity and stability at the boiling point of water.
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Affiliation(s)
- Ksenia Egorova
- Institute of Technical Microbiology, Hamburg University of Technology, Kasernenstr. 12, 21073 Hamburg, Germany
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Antranikian G, Vorgias CE, Bertoldo C. Extreme environments as a resource for microorganisms and novel biocatalysts. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2005; 96:219-62. [PMID: 16566093 DOI: 10.1007/b135786] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The steady increase in the number of newly isolated extremophilic microorganisms and the discovery of their enzymes by academic and industrial institutions underlines the enormous potential of extremophiles for application in future biotechnological processes. Enzymes from extremophilic microorganisms offer versatile tools for sustainable developments in a variety of industrial application as they show important environmental benefits due to their biodegradability, specific stability under extreme conditions, improved use of raw materials and decreased amount of waste products. Although major advances have been made in the last decade, our knowledge of the physiology, metabolism, enzymology and genetics of this fascinating group of extremophilic microorganisms and their related enzymes is still limited. In-depth information on the molecular properties of the enzymes and their genes, however, has to be obtained to analyze the structure and function of proteins that are catalytically active around the boiling and freezing points of water and extremes of pH. New techniques, such as genomics, metanogenomics, DNA evolution and gene shuffling, will lead to the production of enzymes that are highly specific for countless industrial applications. Due to the unusual properties of enzymes from extremophiles, they are expected to optimize already existing processes or even develop new sustainable technologies.
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Affiliation(s)
- Garabed Antranikian
- Institute of Technical Microbiology, Technical University Hamburg-Harburg, Kasernenstrasse 12, 21073 Hamburg, Germany.
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26
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Rhee JK, Ahn DG, Kim YG, Oh JW. New thermophilic and thermostable esterase with sequence similarity to the hormone-sensitive lipase family, cloned from a metagenomic library. Appl Environ Microbiol 2005; 71:817-25. [PMID: 15691936 PMCID: PMC546692 DOI: 10.1128/aem.71.2.817-825.2005] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A gene coding for a thermostable esterase was isolated by functional screening of Escherichia coli cells that had been transformed with fosmid environmental DNA libraries constructed with metagenomes from thermal environmental samples. The gene conferring esterase activity on E. coli grown on tributyrin agar was composed of 936 bp, corresponding to 311 amino acid residues with a molecular mass of 34 kDa. The enzyme showed significant amino acid similarity (64%) to the enzyme from a hyperthermophilic archaeon, Pyrobaculum calidifontis. An amino acid sequence comparison with other esterases and lipases revealed that the enzyme should be classified as a new member of the hormone-sensitive lipase family. The recombinant esterase that was overexpressed and purified from E. coli was active above 30 degrees C up to 95 degrees C and had a high thermal stability. It displayed a high degree of activity in a pH range of 5.5 to 7.5, with an optimal pH of approximately 6.0. The best substrate for the enzyme among the p-nitrophenyl esters (C(4) to C(16)) examined was p-nitrophenyl caproate (C(6)), and no lipolytic activity was observed with esters containing an acyl chain length of longer than 10 carbon atoms, indicating that the enzyme is an esterase and not a lipase.
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Affiliation(s)
- Jin-Kyu Rhee
- Department of Biotechnology, Yonsei University, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-749, Korea
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27
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Ravot G, Buteux D, Favre-Bulle O, Wahler D, Veit T, Lefèvre F. Screening for Thermostable Esterases: From Deep Sea to Industry. Eng Life Sci 2004. [DOI: 10.1002/elsc.200402149] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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28
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Gianfreda L, Rao MA. Potential of extra cellular enzymes in remediation of polluted soils: a review. Enzyme Microb Technol 2004. [DOI: 10.1016/j.enzmictec.2004.05.006] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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Suzuki Y, Miyamoto K, Ohta H. A novel thermostable esterase from the thermoacidophilic archaeonSulfolobus tokodaiistrain 7. FEMS Microbiol Lett 2004. [DOI: 10.1111/j.1574-6968.2004.tb09633.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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31
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Abstract
Archaea have developed a variety of molecular strategies to survive the often harsh environments in which they exist. Although the rules that allow archaeal enzymes to fulfill their catalytic functions under extremes of salinity, temperature or pressure are not completely understood, the stability of these extremophilic enzymes, or extremozymes, in the face of adverse conditions has led to their use in a variety of biotechnological applications in which such tolerances are advantageous. In the following, examples of commercially important archaeal extremozymes are presented, potentially useful archaeal extremozyme sources are identified and solutions to obstacles currently hindering wider use of archaeal extremozymes are discussed.
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Affiliation(s)
- J Eichler
- Department of Life Sciences, Ben Gurion University, P.O. Box 653, Beersheva 84105, Israel.
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32
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Gao R, Feng Y, Ishikawa K, Ishida H, Ando S, Kosugi Y, Cao S. Cloning, purification and properties of a hyperthermophilic esterase from archaeon Aeropyrum pernix K1. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1381-1177(03)00064-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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33
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Hotta Y, Ezaki S, Atomi H, Imanaka T. Extremely stable and versatile carboxylesterase from a hyperthermophilic archaeon. Appl Environ Microbiol 2002; 68:3925-31. [PMID: 12147492 PMCID: PMC124002 DOI: 10.1128/aem.68.8.3925-3931.2002] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have found that the hyperthermophilic archaeon Pyrobaculum calidifontis VA1 produced a thermostable esterase. We isolated and sequenced the esterase gene (est(Pc)) from strain VA1. est(Pc) consisted of 939 bp, corresponding to 313 amino acid residues with a molecular mass of 34,354 Da. As est(Pc) showed significant identity (30%) to mammalian hormone-sensitive lipases (HSLs), esterase of P. calidifontis (Est) could be regarded as a new member of the HSL family. Activity levels of the enzyme were comparable or higher than those of previously reported enzymes not only at high temperature (6,410 U/mg at 90 degrees C), but also at ambient temperature (1,050 U/mg at 30 degrees C). The enzyme displayed extremely high thermostability and was also stable after incubation with various water-miscible organic solvents at a concentration of 80%. The enzyme also exhibited activity in the presence of organic solvents. Est of P. calidifontis showed higher hydrolytic activity towards esters with short to medium chains, with p-nitrophenyl caproate (C(6)) the best substrate among the p-nitrophenyl esters examined. As for the alcoholic moiety, the enzyme displayed esterase activity towards esters with both straight- and branched-chain alcohols. Most surprisingly, we found that this Est enzyme hydrolyzed the tertiary alcohol ester tert-butyl acetate, a feature very rare among previously reported lipolytic enzymes. The extreme stability against heat and organic solvents, along with its activity towards a tertiary alcohol ester, indicates a high potential for the Est of P. calidifontis in future applications.
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Affiliation(s)
- Yuji Hotta
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan
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Bornscheuer UT. Microbial carboxyl esterases: classification, properties and application in biocatalysis. FEMS Microbiol Rev 2002; 26:73-81. [PMID: 12007643 DOI: 10.1111/j.1574-6976.2002.tb00599.x] [Citation(s) in RCA: 620] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Esterases (EC 3.1.1.x) represent a diverse group of hydrolases catalyzing the cleavage and formation of ester bonds and are widely distributed in animals, plants and microorganisms. Beside lipases, a considerable number of microbial carboxyl esterases have also been discovered and overexpressed. This review summarizes their properties and classification. Special emphasis is given on their application in organic synthesis for the resolution of racemates and prostereogenic compounds. In addition, recent results for altering their properties by directed evolution are presented.
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Affiliation(s)
- Uwe T Bornscheuer
- Institute for Chemistry and Biochemistry, Department of Technical Chemistry and Biotechnology, Greifswald University, Soldmannstr. 16, Greifswald, Germany.
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Morana A, Di Prizito N, Aurilia V, Rossi M, Cannio R. A carboxylesterase from the hyperthermophilic archaeon Sulfolobus solfataricus: cloning of the gene, characterization of the protein. Gene 2002; 283:107-15. [PMID: 11867217 DOI: 10.1016/s0378-1119(01)00879-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A genomic library of the hyperthermophilic archaeon Sulfolobus solfataricus strain MT4 was constructed in Escherichia coli using a cloning vector not designed for heterologous gene expression. One positive clone exhibiting acquired thermophilic acetylesterase activity was directly detected by an in situ plate assay using a colony staining procedure with the chromogenic substrate beta-naphthyl acetate. The plasmid isolated from the clone contained a 3.3 kb genomic fragment from S. solfataricus and a full-length esterase coding sequence could be identified. Expression of the active thermostable esterase in E. coli was independent of isopropyl-beta-D-thiogalactopyranoside and of the kind of vector, suggesting that the archaeal esterase gene was controlled by fortuitous bacterial-like sequences present in its own 5' flanking region, not by the bacterial lac promoter or other serendipitous vector-located sequences. The protein, partially purified by thermoprecipitation of the host proteins at high temperature and gel exclusion chromatography, showed a homo-tetrameric structure with a subunit of molecular mass of 32 kDa which was in perfect agreement with that deduced from the cloned gene. The same protein was revealed in S. solfataricus cell extracts, thus demonstrating its functional occurrence in vivo under the cell culture conditions tested. The recombinant enzyme exhibited high thermal activity and thermostability with optimal activity between pH 6.5 and 7.0. The hydrolysis of p-nitrophenyl esters of fatty acids (from C(2) to C(8)) allowed the enzyme to be classified as a short length acyl esterase.
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Affiliation(s)
- Alessandra Morana
- Istituto di Biochimica delle Proteine ed Enzimologia, CNR, Via P. Castellino, 111, 80131, Naples, Italy
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Abstract
The industrial application of enzymes that can withstand harsh conditions has greatly increased over the past decade. This is mainly a result of the discovery of novel enzymes from extremophilic microorganisms. Recent advances in the study of extremozymes point to the acceleration of this trend. In particular, enzymes from thermophilic organisms have found the most practical commercial use to date because of their overall inherent stability. This has also led to a greater understanding of stability factors involved in adaptation of these enzymes to their unusual environments.
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37
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Sehgal AC, Callen W, Mathur EJ, Short JM, Kelly RM. Carboxylesterase from Sulfolobus solfataricus P1. Methods Enzymol 2001; 330:461-71. [PMID: 11210525 DOI: 10.1016/s0076-6879(01)30398-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- A C Sehgal
- Department of Chemical Engineering, North Carolina State University, Raleigh, North Carolina 27606, USA
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38
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Vieille C, Zeikus GJ. Hyperthermophilic enzymes: sources, uses, and molecular mechanisms for thermostability. Microbiol Mol Biol Rev 2001; 65:1-43. [PMID: 11238984 PMCID: PMC99017 DOI: 10.1128/mmbr.65.1.1-43.2001] [Citation(s) in RCA: 1392] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enzymes synthesized by hyperthermophiles (bacteria and archaea with optimal growth temperatures of > 80 degrees C), also called hyperthermophilic enzymes, are typically thermostable (i.e., resistant to irreversible inactivation at high temperatures) and are optimally active at high temperatures. These enzymes share the same catalytic mechanisms with their mesophilic counterparts. When cloned and expressed in mesophilic hosts, hyperthermophilic enzymes usually retain their thermal properties, indicating that these properties are genetically encoded. Sequence alignments, amino acid content comparisons, crystal structure comparisons, and mutagenesis experiments indicate that hyperthermophilic enzymes are, indeed, very similar to their mesophilic homologues. No single mechanism is responsible for the remarkable stability of hyperthermophilic enzymes. Increased thermostability must be found, instead, in a small number of highly specific alterations that often do not obey any obvious traffic rules. After briefly discussing the diversity of hyperthermophilic organisms, this review concentrates on the remarkable thermostability of their enzymes. The biochemical and molecular properties of hyperthermophilic enzymes are described. Mechanisms responsible for protein inactivation are reviewed. The molecular mechanisms involved in protein thermostabilization are discussed, including ion pairs, hydrogen bonds, hydrophobic interactions, disulfide bridges, packing, decrease of the entropy of unfolding, and intersubunit interactions. Finally, current uses and potential applications of thermophilic and hyperthermophilic enzymes as research reagents and as catalysts for industrial processes are described.
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Affiliation(s)
- C Vieille
- Biochemistry Department, Michigan State University, East Lansing, Michigan 48824, USA
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39
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Abstract
Extremozymes offer new opportunities for biocatalysis and biotransformations as a result of their extreme stability. From recent work, major approaches to extending the range of applications of extremozymes have emerged. Both the discovery of new extremophilic species and the determination of genome sequences provide a route to new enzymes, with the possibility that these will lead to novel applications. Of equal importance, protein engineering and directed evolution provide approaches to improve enzyme stability and modify specificity in ways that may not exist in the natural world.
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Affiliation(s)
- D W Hough
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY UK.
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