1
|
Assessing the impact of substrate-level enzyme regulations limiting ethanol titer in Clostridium thermocellum using a core kinetic model. Metab Eng 2022; 69:286-301. [PMID: 34982997 DOI: 10.1016/j.ymben.2021.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/16/2021] [Accepted: 12/29/2021] [Indexed: 11/20/2022]
Abstract
Clostridium thermocellum is a promising candidate for consolidated bioprocessing because it can directly ferment cellulose to ethanol. Despite significant efforts, achieved yields and titers fall below industrially relevant targets. This implies that there still exist unknown enzymatic, regulatory, and/or possibly thermodynamic bottlenecks that can throttle back metabolic flow. By (i) elucidating internal metabolic fluxes in wild-type C. thermocellum grown on cellobiose via 13C-metabolic flux analysis (13C-MFA), (ii) parameterizing a core kinetic model, and (iii) subsequently deploying an ensemble-docking workflow for discovering substrate-level regulations, this paper aims to reveal some of these factors and expand our knowledgebase governing C. thermocellum metabolism. Generated 13C labeling data were used with 13C-MFA to generate a wild-type flux distribution for the metabolic network. Notably, flux elucidation through MFA alluded to serine generation via the mercaptopyruvate pathway. Using the elucidated flux distributions in conjunction with batch fermentation process yield data for various mutant strains, we constructed a kinetic model of C. thermocellum core metabolism (i.e. k-ctherm138). Subsequently, we used the parameterized kinetic model to explore the effect of removing substrate-level regulations on ethanol yield and titer. Upon exploring all possible simultaneous (up to four) regulation removals we identified combinations that lead to many-fold model predicted improvement in ethanol titer. In addition, by coupling a systematic method for identifying putative competitive inhibitory mechanisms using K-FIT kinetic parameterization with the ensemble-docking workflow, we flagged 67 putative substrate-level inhibition mechanisms across central carbon metabolism supported by both kinetic formalism and docking analysis.
Collapse
|
2
|
β-Glucan phosphorylases in carbohydrate synthesis. Appl Microbiol Biotechnol 2021; 105:4073-4087. [PMID: 33970317 PMCID: PMC8140972 DOI: 10.1007/s00253-021-11320-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 01/02/2023]
Abstract
Abstract β-Glucan phosphorylases are carbohydrate-active enzymes that catalyze the reversible degradation of β-linked glucose polymers, with outstanding potential for the biocatalytic bottom-up synthesis of β-glucans as major bioactive compounds. Their preference for sugar phosphates (rather than nucleotide sugars) as donor substrates further underlines their significance for the carbohydrate industry. Presently, they are classified in the glycoside hydrolase families 94, 149, and 161 (www.cazy.org). Since the discovery of β-1,3-oligoglucan phosphorylase in 1963, several other specificities have been reported that differ in linkage type and/or degree of polymerization. Here, we present an overview of the progress that has been made in our understanding of β-glucan and associated β-glucobiose phosphorylases, with a special focus on their application in the synthesis of carbohydrates and related molecules. Key points • Discovery, characteristics, and applications of β-glucan phosphorylases. • β-Glucan phosphorylases in the production of functional carbohydrates.
Collapse
|
3
|
Sun S, You C. Disaccharide phosphorylases: Structure, catalytic mechanisms and directed evolution. Synth Syst Biotechnol 2021; 6:23-31. [PMID: 33665389 PMCID: PMC7896129 DOI: 10.1016/j.synbio.2021.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/13/2021] [Accepted: 01/31/2021] [Indexed: 12/16/2022] Open
Abstract
Disaccharide phosphorylases (DSPs) are carbohydrate-active enzymes with outstanding potential for the biocatalytic conversion of common table sugar into products with attractive properties. They are modular enzymes that form active homo-oligomers. From a mechanistic as well as a structural point of view, they are similar to glycoside hydrolases or glycosyltransferases. As the majority of DSPs show strict stereo- and regiospecificities, these enzymes were used to synthesize specific disaccharides. Currently, protein engineering of DSPs is pursued in different laboratories to broaden the donor and acceptor substrate specificities or improve the industrial particularity of naturally existing enzymes, to eventually generate a toolbox of new catalysts for glycoside synthesis. Herein we review the characteristics and classifications of reported DSPs and the glycoside products that they have been used to synthesize.
Collapse
Affiliation(s)
- Shangshang Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, People’s Republic of China
| | - Chun You
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, People’s Republic of China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing, 100049, People’s Republic of China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, People’s Republic of China
| |
Collapse
|
4
|
Benkoulouche M, Fauré R, Remaud-Siméon M, Moulis C, André I. Harnessing glycoenzyme engineering for synthesis of bioactive oligosaccharides. Interface Focus 2019; 9:20180069. [PMID: 30842872 DOI: 10.1098/rsfs.2018.0069] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2018] [Indexed: 12/13/2022] Open
Abstract
Combined with chemical synthesis, the use of glycoenzyme biocatalysts has shown great synthetic potential over recent decades owing to their remarkable versatility in terms of substrates and regio- and stereoselectivity that allow structurally controlled synthesis of carbohydrates and glycoconjugates. Nonetheless, the lack of appropriate enzymatic tools with requisite properties in the natural diversity has hampered extensive exploration of enzyme-based synthetic routes to access relevant bioactive oligosaccharides, such as cell-surface glycans or prebiotics. With the remarkable progress in enzyme engineering, it has become possible to improve catalytic efficiency and physico-chemical properties of enzymes but also considerably extend the repertoire of accessible catalytic reactions and tailor novel substrate specificities. In this review, we intend to give a brief overview of the advantageous use of engineered glycoenzymes, sometimes in combination with chemical steps, for the synthesis of natural bioactive oligosaccharides or their precursors. The focus will be on examples resulting from the three main classes of glycoenzymes specialized in carbohydrate synthesis: glycosyltransferases, glycoside hydrolases and glycoside phosphorylases.
Collapse
Affiliation(s)
- Mounir Benkoulouche
- Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, LISBP, Université de Toulouse, CNRS, INRA, INSA, 135, avenue de Rangueil, 31077 Toulouse cedex 04, France
| | - Régis Fauré
- Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, LISBP, Université de Toulouse, CNRS, INRA, INSA, 135, avenue de Rangueil, 31077 Toulouse cedex 04, France
| | - Magali Remaud-Siméon
- Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, LISBP, Université de Toulouse, CNRS, INRA, INSA, 135, avenue de Rangueil, 31077 Toulouse cedex 04, France
| | - Claire Moulis
- Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, LISBP, Université de Toulouse, CNRS, INRA, INSA, 135, avenue de Rangueil, 31077 Toulouse cedex 04, France
| | - Isabelle André
- Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, LISBP, Université de Toulouse, CNRS, INRA, INSA, 135, avenue de Rangueil, 31077 Toulouse cedex 04, France
| |
Collapse
|
5
|
Meng D, Wei X, Zhang YHPJ, Zhu Z, You C, Ma Y. Stoichiometric Conversion of Cellulosic Biomass by in Vitro Synthetic Enzymatic Biosystems for Biomanufacturing. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02473] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dongdong Meng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, People’s Republic of China
| | - Xinlei Wei
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, People’s Republic of China
| | - Yi-Heng P. Job Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, People’s Republic of China
| | - Zhiguang Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, People’s Republic of China
| | - Chun You
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, People’s Republic of China
| | - Yanhe Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, People’s Republic of China
| |
Collapse
|
6
|
Prajapati AS, Panchal KJ, Pawar VA, Noronha MJ, Patel DH, Subramanian RB. Review on Cellulase and Xylanase Engineering for Biofuel Production. Ind Biotechnol (New Rochelle N Y) 2018. [DOI: 10.1089/ind.2017.0027] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Anil S. Prajapati
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Ketankumar J. Panchal
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Vishakha A. Pawar
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Monica J. Noronha
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| | - Darshan H. Patel
- P. D. Patel Institute of Applied Sciences, Charotar University of Science and Technology Gujarat, India
| | - R. B. Subramanian
- P.G. Department of Biosciences, UGC-Centre of Advanced Studies, Satellite campus, Sardar Patel Maidan, Sardar Patel University, Gujarat, India
| |
Collapse
|
7
|
Zhang YHP, Sun J, Ma Y. Biomanufacturing: history and perspective. ACTA ACUST UNITED AC 2017; 44:773-784. [PMID: 27837351 DOI: 10.1007/s10295-016-1863-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 10/30/2016] [Indexed: 01/09/2023]
Abstract
Abstract
Biomanufacturing is a type of manufacturing that utilizes biological systems (e.g., living microorganisms, resting cells, animal cells, plant cells, tissues, enzymes, or in vitro synthetic (enzymatic) systems) to produce commercially important biomolecules for use in the agricultural, food, material, energy, and pharmaceutical industries. History of biomanufacturing could be classified into the three revolutions in terms of respective product types (mainly), production platforms, and research technologies. Biomanufacturing 1.0 focuses on the production of primary metabolites (e.g., butanol, acetone, ethanol, citric acid) by using mono-culture fermentation; biomanufacturing 2.0 focuses on the production of secondary metabolites (e.g., penicillin, streptomycin) by using a dedicated mutant and aerobic submerged liquid fermentation; and biomanufacturing 3.0 focuses on the production of large-size biomolecules—proteins and enzymes (e.g., erythropoietin, insulin, growth hormone, amylase, DNA polymerase) by using recombinant DNA technology and advanced cell culture. Biomanufacturing 4.0 could focus on new products, for example, human tissues or cells made by regenerative medicine, artificial starch made by in vitro synthetic biosystems, isobutanol fermented by metabolic engineering, and synthetic biology-driven microorganisms, as well as exiting products produced by far better approaches. Biomanufacturing 4.0 would help address some of the most important challenges of humankind, such as food security, energy security and sustainability, water crisis, climate change, health issues, and conflict related to the energy, food, and water nexus.
Collapse
Affiliation(s)
- Yi-Heng Percival Zhang
- 0000000119573309 grid.9227.e Tianjin Institute of Industrial Biotechnology Chinese Academy of Science 32 West 7th Avenue, Tianjin Airport Economic Area 300308 Tianjin China
- 0000 0001 0694 4940 grid.438526.e Biological Systems Engineering Department Virginia Tech 304 Seitz Hall 24061 Blacksburg VA USA
| | - Jibin Sun
- 0000000119573309 grid.9227.e Tianjin Institute of Industrial Biotechnology Chinese Academy of Science 32 West 7th Avenue, Tianjin Airport Economic Area 300308 Tianjin China
| | - Yanhe Ma
- 0000000119573309 grid.9227.e Tianjin Institute of Industrial Biotechnology Chinese Academy of Science 32 West 7th Avenue, Tianjin Airport Economic Area 300308 Tianjin China
| |
Collapse
|
8
|
Zhong C, Wei P, Zhang YHP. A kinetic model of one-pot rapid biotransformation of cellobiose from sucrose catalyzed by three thermophilic enzymes. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2016.11.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
9
|
Abstract
This article defines protein stability, emphasizes its importance and surveys the field of protein stabilization, with summary reference to a selection of 2009-2015 publications. One can enhance stability by, in particular, protein engineering strategies and by chemical modification (including conjugation) in solution. General protocols are set out on how to measure a given protein's (1) kinetic thermal stability, and (2) oxidative stability, and (3) how to undertake chemical modification of a protein in solution.
Collapse
Affiliation(s)
- Ciarán Ó'Fágáin
- School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland.
- National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland.
| |
Collapse
|
10
|
|
11
|
Zhang YHP. Production of biofuels and biochemicals by in vitro synthetic biosystems: Opportunities and challenges. Biotechnol Adv 2015; 33:1467-83. [DOI: 10.1016/j.biotechadv.2014.10.009] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 10/09/2014] [Accepted: 10/19/2014] [Indexed: 12/20/2022]
|
12
|
Zhang J, Shi H, Xu L, Zhu X, Li X. Site-Directed Mutagenesis of a Hyperthermophilic Endoglucanase Cel12B from Thermotoga maritima Based on Rational Design. PLoS One 2015. [PMID: 26218520 PMCID: PMC4517919 DOI: 10.1371/journal.pone.0133824] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To meet the demand for the application of high activity and thermostable cellulases in the production of new-generation bioethanol from nongrain-cellulose sources, a hyperthermostable β-1,4-endoglucase Cel12B from Thermotoga maritima was selected for further modification by gene site-directed mutagenesis method in the present study, based on homology modeling and rational design. As a result, two recombinant enzymes showed significant improvement in enzyme activity by 77% and 87%, respectively, higher than the parental enzyme TmCel12B. Furthermore, the two mutants could retain 80% and 90.5% of their initial activity after incubation at 80°C for 8 h, while only 45% for 5 h to TmCel12B. The Km and Vmax of the two recombinant enzymes were 1.97±0.05 mM, 4.23±0.15 μmol·mg(-1)·min(-1) of TmCel12B-E225H-K207G-D37V, and 2.97±0.12 mM, 3.15±0.21 μmol·mg(-1)·min(-1) of TmCel12B-E225H-K207G, respectively, when using CMC-Na as the substrate. The roles of the mutation sites were also analyzed and evaluated in terms of electron density, hydrophobicity of the modeled protein structures. The recombinant enzymes may be used in the hydrolysis of cellulose at higher temperature in the future. It was concluded that the gene mutagenesis approach of a certain active residues may effectively improve the performance of cellulases for the industrial applications and contribute to the study the thermostable mechanism of thermophilic enzymes.
Collapse
Affiliation(s)
- Jinfeng Zhang
- Jiangsu Provincial Engineering Laboratory for Biomass Conversion and Process Integration, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
- School of Life Science and Chemical Engineering, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
| | - Hao Shi
- Jiangsu Provincial Engineering Laboratory for Biomass Conversion and Process Integration, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
| | - Linyu Xu
- Jiangsu Provincial Engineering Laboratory for Biomass Conversion and Process Integration, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
- School of Life Science and Chemical Engineering, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
| | - Xiaoyan Zhu
- Jiangsu Provincial Engineering Laboratory for Biomass Conversion and Process Integration, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
- School of Life Science and Chemical Engineering, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
- Jiangsu Key Laboratory for Biomass-based Energy and Enzyme Technology, Huaiyin Normal University, Huaian, Jiangsu 223300, P. R. China
| | - Xiangqian Li
- Jiangsu Provincial Engineering Laboratory for Biomass Conversion and Process Integration, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
- School of Life Science and Chemical Engineering, Huaiyin Institute of Technology, Huaian, Jiangsu 223003, P. R. China
- * E-mail:
| |
Collapse
|
13
|
Kapoor S, Rafiq A, Sharma S. Protein engineering and its applications in food industry. Crit Rev Food Sci Nutr 2015; 57:2321-2329. [DOI: 10.1080/10408398.2014.1000481] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Swati Kapoor
- Department of Food Science and Technology, Punjab Agricultural University, Ludhiana, India
| | - Aasima Rafiq
- Department of Food Science and Technology, Punjab Agricultural University, Ludhiana, India
| | - Savita Sharma
- Department of Food Science and Technology, Punjab Agricultural University, Ludhiana, India
| |
Collapse
|
14
|
Puchart V. Glycoside phosphorylases: Structure, catalytic properties and biotechnological potential. Biotechnol Adv 2015; 33:261-76. [DOI: 10.1016/j.biotechadv.2015.02.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 02/06/2015] [Accepted: 02/07/2015] [Indexed: 12/20/2022]
|
15
|
You C, Chen H, Myung S, Sathitsuksanoh N, Ma H, Zhang XZ, Li J, Zhang YHP. Enzymatic transformation of nonfood biomass to starch. Proc Natl Acad Sci U S A 2013; 110:7182-7. [PMID: 23589840 PMCID: PMC3645547 DOI: 10.1073/pnas.1302420110] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The global demand for food could double in another 40 y owing to growth in the population and food consumption per capita. To meet the world's future food and sustainability needs for biofuels and renewable materials, the production of starch-rich cereals and cellulose-rich bioenergy plants must grow substantially while minimizing agriculture's environmental footprint and conserving biodiversity. Here we demonstrate one-pot enzymatic conversion of pretreated biomass to starch through a nonnatural synthetic enzymatic pathway composed of endoglucanase, cellobiohydrolyase, cellobiose phosphorylase, and alpha-glucan phosphorylase originating from bacterial, fungal, and plant sources. A special polypeptide cap in potato alpha-glucan phosphorylase was essential to push a partially hydrolyzed intermediate of cellulose forward to the synthesis of amylose. Up to 30% of the anhydroglucose units in cellulose were converted to starch; the remaining cellulose was hydrolyzed to glucose suitable for ethanol production by yeast in the same bioreactor. Next-generation biorefineries based on simultaneous enzymatic biotransformation and microbial fermentation could address the food, biofuels, and environment trilemma.
Collapse
Affiliation(s)
- Chun You
- Biological Systems Engineering Department
| | - Hongge Chen
- Biological Systems Engineering Department
- College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Suwan Myung
- Biological Systems Engineering Department
- Institute for Critical Technology and Applied Science, and
| | - Noppadon Sathitsuksanoh
- Biological Systems Engineering Department
- Institute for Critical Technology and Applied Science, and
| | - Hui Ma
- Gate Fuels, Inc., Blacksburg, VA 24060
| | - Xiao-Zhou Zhang
- Biological Systems Engineering Department
- Gate Fuels, Inc., Blacksburg, VA 24060
| | - Jianyong Li
- Biochemistry Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Y.-H. Percival Zhang
- Biological Systems Engineering Department
- Institute for Critical Technology and Applied Science, and
- Gate Fuels, Inc., Blacksburg, VA 24060
- BioEnergy Science Center, Department of Energy, Oak Ridge, TN 37831; and
- Cell Free Bioinnovations, Inc., Blacksburg, VA 24060
| |
Collapse
|
16
|
Singh RK, Tiwari MK, Singh R, Lee JK. From protein engineering to immobilization: promising strategies for the upgrade of industrial enzymes. Int J Mol Sci 2013; 14:1232-77. [PMID: 23306150 PMCID: PMC3565319 DOI: 10.3390/ijms14011232] [Citation(s) in RCA: 265] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/14/2012] [Accepted: 12/24/2012] [Indexed: 11/16/2022] Open
Abstract
Enzymes found in nature have been exploited in industry due to their inherent catalytic properties in complex chemical processes under mild experimental and environmental conditions. The desired industrial goal is often difficult to achieve using the native form of the enzyme. Recent developments in protein engineering have revolutionized the development of commercially available enzymes into better industrial catalysts. Protein engineering aims at modifying the sequence of a protein, and hence its structure, to create enzymes with improved functional properties such as stability, specific activity, inhibition by reaction products, and selectivity towards non-natural substrates. Soluble enzymes are often immobilized onto solid insoluble supports to be reused in continuous processes and to facilitate the economical recovery of the enzyme after the reaction without any significant loss to its biochemical properties. Immobilization confers considerable stability towards temperature variations and organic solvents. Multipoint and multisubunit covalent attachments of enzymes on appropriately functionalized supports via linkers provide rigidity to the immobilized enzyme structure, ultimately resulting in improved enzyme stability. Protein engineering and immobilization techniques are sequential and compatible approaches for the improvement of enzyme properties. The present review highlights and summarizes various studies that have aimed to improve the biochemical properties of industrially significant enzymes.
Collapse
Affiliation(s)
- Raushan Kumar Singh
- Department of Chemical Engineering, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul 143-701, Korea.
| | | | | | | |
Collapse
|
17
|
Cell-free Biosystems in the Production of Electricity and Bioenergy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 137:125-52. [PMID: 23748347 DOI: 10.1007/10_2013_201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
: Increasing needs of green energy and concerns of climate change are motivating intensive R&D efforts toward the low-cost production of electricity and bioenergy, such as hydrogen, alcohols, and jet fuel, from renewable sugars. Cell-free biosystems for biomanufacturing (CFB2) have been suggested as an emerging platform to replace mainstream microbial fermentation for the cost-effective production of some biocommodities. As compared to whole-cell factories, cell-free biosystems comprised of synthetic enzymatic pathways have numerous advantages, such as high product yield, fast reaction rate, broad reaction condition, easy process control and regulation, tolerance of toxic compound/product, and an unmatched capability of performing unnatural reactions. However, issues pertaining to high costs and low stabilities of enzymes and cofactors as well as compromised optimal conditions for different source enzymes need to be solved before cell-free biosystems are scaled up for biomanufacturing. Here, we review the current status of cell-free technology, update recent advances, and focus on its applications in the production of electricity and bioenergy.
Collapse
|
18
|
You C, Percival Zhang YH. Easy preparation of a large-size random gene mutagenesis library in Escherichia coli. Anal Biochem 2012; 428:7-12. [PMID: 22659340 DOI: 10.1016/j.ab.2012.05.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 11/17/2022]
Abstract
A simple and fast protocol for the preparation of a large-size mutant library for directed evolution in Escherichia coli was developed based on the DNA multimers generated by prolonged overlap extension polymerase chain reaction (POE-PCR). This protocol comprised the following: (i) a linear DNA mutant library was generated by error-prone PCR or shuffling, and a linear vector backbone was prepared by regular PCR; (ii) the DNA multimers were generated based on these two DNA templates by POE-PCR; and (iii) the one restriction enzyme-digested DNA multimers were ligated to circular plasmids, followed by transformation to E. coli. Because the ligation efficiency of one DNA fragment was several orders of magnitude higher than that of two DNA fragments for typical mutant library construction, it was very easy to generate a mutant library with a size of more than 10(7) protein mutants per 50 μl of the POE-PCR product. Via this method, four new fluorescent protein mutants were obtained based on monomeric cherry fluorescent protein. This new protocol was simple and fast because it did not require labor-intensive optimizations in restriction enzyme digestion and ligation, did not involve special plasmid design, and enabled constructing a large-size mutant library for directed enzyme evolution within 1 day.
Collapse
Affiliation(s)
- Chun You
- Biological Systems Engineering Department, Virginia Tech, Blacksburg, VA 24061, USA
| | | |
Collapse
|
19
|
You C, Zhang YHP. Cell-free biosystems for biomanufacturing. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2012; 131:89-119. [PMID: 23111502 DOI: 10.1007/10_2012_159] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Although cell-free biosystems have been used as a tool for investigating fundamental aspects of biological systems for more than 100 years, they are becoming an emerging biomanufacturing platform in the production of low-value biocommodities (e.g., H(2), ethanol, and isobutanol), fine chemicals, and high-value protein and carbohydrate drugs and their precursors. Here we would like to define the cell-free biosystems containing more than three catalytic components in a single reaction vessel, which although different from one-, two-, or three-enzyme biocatalysis can be regarded as a straightforward extension of multienzymatic biocatalysis. In this chapter, we compare the advantages and disadvantages of cell-free biosystems versus living organisms, briefly review the history of cell-free biosystems, highlight a few examples, analyze any remaining obstacles to the scale-up of cell-free biosystems, and suggest potential solutions. Cell-free biosystems could become a disruptive technology to microbial fermentation, especially in the production of high-impact low-value biocommodities mainly due to the very high product yields and potentially low production costs.
Collapse
Affiliation(s)
- Chun You
- Biological Systems Engineering Department, Virginia Tech, 304 Seitz Hall, Blacksburg, VA, 24061, USA
| | | |
Collapse
|