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den Haan R, Rose SH, Cripwell RA, Trollope KM, Myburgh MW, Viljoen-Bloom M, van Zyl WH. Heterologous production of cellulose- and starch-degrading hydrolases to expand Saccharomyces cerevisiae substrate utilization: Lessons learnt. Biotechnol Adv 2021; 53:107859. [PMID: 34678441 DOI: 10.1016/j.biotechadv.2021.107859] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/28/2022]
Abstract
Selected strains of Saccharomyces cerevisiae are used for commercial bioethanol production from cellulose and starch, but the high cost of exogenous enzymes for substrate hydrolysis remains a challenge. This can be addressed through consolidated bioprocessing (CBP) where S. cerevisiae strains are engineered to express recombinant glycoside hydrolases during fermentation. Looking back at numerous strategies undertaken over the past four decades to improve recombinant protein production in S. cerevisiae, it is evident that various steps in the protein production "pipeline" can be manipulated depending on the protein of interest and its anticipated application. In this review, we briefly introduce some of the strategies and highlight lessons learned with regards to improved transcription, translation, post-translational modification and protein secretion of heterologous hydrolases. We examine how host strain selection and modification, as well as enzyme compatibility, are crucial determinants for overall success. Finally, we discuss how lessons from heterologous hydrolase expression can inform modern synthetic biology and genome editing tools to provide process-ready yeast strains in future. However, it is clear that the successful expression of any particular enzyme is still unpredictable and requires a trial-and-error approach.
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Affiliation(s)
- Riaan den Haan
- Department of Biotechnology, University of the Western Cape, Bellville, South Africa
| | - Shaunita H Rose
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Rosemary A Cripwell
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Kim M Trollope
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Marthinus W Myburgh
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | | | - Willem H van Zyl
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
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2
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Wang J, Ma Y, Zhang K, Yang H, Liu C, Zou S, Hong J, Zhang M. Mating type and ploidy effect on the β-glucosidase activity and ethanol-producing performance of Saccharomyces cerevisiae with multiple δ-integrated bgl 1 gene. J Biotechnol 2016; 231:24-31. [DOI: 10.1016/j.jbiotec.2016.05.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/20/2016] [Accepted: 05/20/2016] [Indexed: 11/15/2022]
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3
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Ethanol production from acid- and alkali-pretreated corncob by endoglucanase and β-glucosidase co-expressing Saccharomyces cerevisiae subject to the expression of heterologous genes and nutrition added. World J Microbiol Biotechnol 2016; 32:86. [DOI: 10.1007/s11274-016-2043-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 03/01/2016] [Indexed: 10/22/2022]
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4
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Hong J, Yang H, Zhang K, Liu C, Zou S, Zhang M. Development of a cellulolytic Saccharomyces cerevisiae strain with enhanced cellobiohydrolase activity. World J Microbiol Biotechnol 2014; 30:2985-93. [PMID: 25164958 DOI: 10.1007/s11274-014-1726-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 08/20/2014] [Indexed: 11/27/2022]
Abstract
Consolidated bioprocessing (CBP) is a promising technology for lignocellulosic ethanol production, and the key is the engineering of a microorganism that can efficiently utilize cellulose. Development of Saccharomyces cerevisiae for CBP requires high level expression of cellulases, particularly cellobiohydrolases (CBH). In this study, to construct a CBP-enabling yeast with enhanced CBH activity, three cassettes containing constitutively expressed CBH-encoding genes (cbh1 from Aspergillus aculeatus, cbh1 and cbh2 from Trichoderma reesei) were constructed. T. reesei eg2, A. aculeatus bgl1, and the three CBH-encoding genes were then sequentially integrated into the S. cerevisiae W303-1A chromosome via δ-sequence-mediated integration. The resultant strains W1, W2, and W3, expressing uni-, bi-, and trifunctional cellulases, respectively, exhibited corresponding cellulase activities. Furthermore, both the activities and glucose producing activity ascended. The growth test on cellulose containing plates indicated that CBH was a necessary component for successful utilization of crystalline cellulose. The three recombinant strains and the control strains W303-1A and AADY were evaluated in acid- and alkali-pretreated corncob containing media with 5 FPU exogenous cellulase/g biomass loading. The highest ethanol titer (g/l) within 7 days was 5.92 ± 0.51, 18.60 ± 0.81, 28.20 ± 0.84, 1.40 ± 0.12, and 2.12 ± 0.35, respectively. Compared with the control strains, W3 efficiently fermented pretreated corncob to ethanol. To our knowledge, this is the first study aimed at creating cellulolytic yeast with enhanced CBH activity by integrating three types of CBH-encoding gene with a strong constitutive promoter Ptpi.
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Affiliation(s)
- Jiefang Hong
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, 300072, China
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Yang H, Liu C, Zou S, Ma Y, Hong J, Zhang M. Improving bgl1 gene expression in Saccharomyces cerevisiae through meiosis in an isogenic triploid. Biotechnol Lett 2014; 36:1279-85. [PMID: 24563302 PMCID: PMC4000627 DOI: 10.1007/s10529-014-1471-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 01/09/2014] [Indexed: 12/01/2022]
Abstract
Introducing large numbers of target genes into the chromosome of Saccharomyces cerevisiae via δ-sequence-mediated integration is a good strategy for exploring the effects of gene dosage on expression and secretion of heterologous proteins. The expression of exogenous genes might be further improved through meiosis in an isogenic triploid. Here, a stable strain A-8 was screened from 35 sexual spore colonies obtained from an isogenic triploid integratively expressing bgl1 from Aspergillus aculeatus. The corresponding β-glucosidase activity in this strain was increased by ~120 % compared with the parent strain BGL-a. Measurement of doubling time, flow cytometry, and mating experiments further confirmed that A-8 was a spore-forming strain obtained from a triploid parent. Thus, combining δ-integration and meiosis in an isogenic triploid is a promising approach for improving the expression of exogenous proteins in S. cerevisiae.
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Affiliation(s)
- Huajun Yang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,
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Guo C, Jiang N. Physiological and enzymatic comparison between Pichia stipitis and recombinant Saccharomyces cerevisiae on xylose fermentation. World J Microbiol Biotechnol 2012. [PMID: 23180545 DOI: 10.1007/s11274-012-1208-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to better understand the differences in xylose metabolism between natural xylose-utilizing Pichia stipitis and metabolically engineered Saccharomyces cerevisiae, we constructed a series of recombinant S. cerevisiae strains with different xylose reductase/xylitol dehydrogenase/xylulokinase activity ratios by integrating xylitol dehydrogenase gene (XYL2) into the chromosome with variable copies and heterogeneously expressing xylose reductase gene (XYL1) and endogenous xylulokinase gene (XKS1). The strain with the highest specific xylose uptake rate and ethanol productivity on pure xylose fermentation was selected to compare to P. stipitis under oxygen-limited condition. Physiological and enzymatic comparison showed that they have different patterns of xylose metabolism and NADPH generation.
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Affiliation(s)
- Changying Guo
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
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Siddiqui MS, Thodey K, Trenchard I, Smolke CD. Advancing secondary metabolite biosynthesis in yeast with synthetic biology tools. FEMS Yeast Res 2012; 12:144-70. [PMID: 22136110 DOI: 10.1111/j.1567-1364.2011.00774.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 11/18/2011] [Accepted: 11/19/2011] [Indexed: 12/11/2022] Open
Abstract
Secondary metabolites are an important source of high-value chemicals, many of which exhibit important pharmacological properties. These valuable natural products are often difficult to synthesize chemically and are commonly isolated through inefficient extractions from natural biological sources. As such, they are increasingly targeted for production by biosynthesis from engineered microorganisms. The budding yeast species Saccharomyces cerevisiae has proven to be a powerful microorganism for heterologous expression of biosynthetic pathways. S. cerevisiae's usefulness as a host organism is owed in large part to the wealth of knowledge accumulated over more than a century of intense scientific study. Yet many challenges are currently faced in engineering yeast strains for the biosynthesis of complex secondary metabolite production. However, synthetic biology is advancing the development of new tools for constructing, controlling, and optimizing complex metabolic pathways in yeast. Here, we review how the coupling between yeast biology and synthetic biology is advancing the use of S. cerevisiae as a microbial host for the construction of secondary metabolic pathways.
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Affiliation(s)
- Michael S Siddiqui
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
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Kilonzo P, Margaritis A, Bergougnou M. Airlift-driven fibrous-bed bioreactor for continuous production of glucoamylase using immobilized recombinant yeast cells. J Biotechnol 2009; 143:60-8. [PMID: 19539672 DOI: 10.1016/j.jbiotec.2009.06.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 05/03/2009] [Accepted: 06/05/2009] [Indexed: 10/20/2022]
Abstract
Continuous production of a fungal glucoamylase by immobilized recombinant Saccharomyces cerevisiae strain C468 containing plasmid pGAC9. Yeast cells were immobilized on hydrophilic cotton cloth in an inverse internal loop airlift-driven bioreactor. Free-cell culture in the airlift and stirred tank bioreactors confirmed the plasmid instability of the recombinant yeast. Enhanced glucoamylase productivity and plasmid stability were observed both in the free and immobilized cell cultures in the airlift bioreactor system. The glucoamylase level of the free-cell culture in the airlift bioreactor was approximately 20% higher than that in the in stirred tank bioreactor due to high cell density (cell dry weight/volume of bioreactor) and fraction of the plasmid-carrying cells. A potentially high glucoamylase activity of 161U/L and a corresponding volumetric productivity of 3.5U/Lh were achieved when a cell density of approximately 85g/L (or 12.3g/g fiber) was attained in the fibrous-bed immobilized cell bioreactor system. The stable glucoamylase production was achieved after five generations, at which time a fraction of approximately 62% of the plasmid-carrying cells was realized in the immobilized cell system. Plasmid stability was increased for the immobilized cells during continuous culture at the operating dilution rate. The volumetric and specific productivities and fraction of plasmid-carrying cells in the immobilized cell system were higher than in the free-cell counterpart, however. This was in part due to the high viability (approximately 80%) in the immobilized cell system and the selective immobilization of the plasmid-carrying cells in the fibrous bed, and perhaps increased plasmid copy number.
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Affiliation(s)
- Peter Kilonzo
- Department of Chemical and Biochemical Engineering, University of Western Ontario, Ontario, Canada
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Plasmid stability and kinetics of continuous production of glucoamylase by recombinant Saccharomyces cerevisiae in an airlift bioreactor. J Ind Microbiol Biotechnol 2009; 36:1157-69. [PMID: 19504139 DOI: 10.1007/s10295-009-0597-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 05/11/2009] [Indexed: 10/20/2022]
Abstract
Production of glucoamylase by recombinant Saccharomyces cerevisiae C468/pGAC9 (ATCC 20690) in a continuous stirred tank bioreactor was studied at different dilution rates. Plasmid stability was found to be growth (dilution rate) dependent; it increased with the dilution rate. Bioreactor productivity and specific productivity also increased with the dilution rate. A kinetic equation was used to model the plasmid stability kinetics. The growth rate ratio between plasmid-carrying and plasmid-free cells decreased from 1.397 to 1.215, and segregational instability or probability of plasmid loss from each cell division decreased from 0.059 to 0.020 as the dilution rate increased from 0.10 to 0.37 1/h. The specific growth rates increased with dilution rate, while the growth rate difference between plasmid-carrying and plasmid-free cell populations was negligible. This was attributed to the low copy number of the hybrid plasmid pGAC9. Thus, the growth rate had no significant effect on plasmid instability. The proposed kinetics was consistent with experimental results, and the model simulated the experimental data well.
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Abstract
The traditional use of the yeast Saccharomyces cerevisiae in alcoholic fermentation has, over time, resulted in substantial accumulated knowledge concerning genetics, physiology, and biochemistry as well as genetic engineering and fermentation technologies. S. cerevisiae has become a platform organism for developing metabolic engineering strategies, methods, and tools. The current review discusses the relevance of several engineering strategies, such as rational and inverse metabolic engineering, evolutionary engineering, and global transcription machinery engineering, in yeast strain improvement. It also summarizes existing tools for fine-tuning and regulating enzyme activities and thus metabolic pathways. Recent examples of yeast metabolic engineering for food, beverage, and industrial biotechnology (bioethanol and bulk and fine chemicals) follow. S. cerevisiae currently enjoys increasing popularity as a production organism in industrial ("white") biotechnology due to its inherent tolerance of low pH values and high ethanol and inhibitor concentrations and its ability to grow anaerobically. Attention is paid to utilizing lignocellulosic biomass as a potential substrate.
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Latorre-García L, Adam AC, Manzanares P, Polaina J. Improving the amylolytic activity of Saccharomyces cerevisiae glucoamylase by the addition of a starch binding domain. J Biotechnol 2005; 118:167-76. [PMID: 15963591 DOI: 10.1016/j.jbiotec.2005.03.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Revised: 01/26/2005] [Accepted: 03/18/2005] [Indexed: 10/25/2022]
Abstract
Glucoamylase produced by amylolytic strains of Saccharomyces cerevisiae (var. diastaticus) lacks a starch binding domain that is present in homologous glucoamylases from Aspergillus niger and other filamentous fungi. The absence of the binding domain makes the enzyme inefficient against raw starch and hence unsuitable for most biotechnological applications. We have constructed a hybrid glucoamylase-encoding gene by in-frame fusion of the S. cerevisiae STA1 gene and DNA fragment that encodes the starch binding domain of A. niger glucoamylase. The hybrid enzyme resulting from expression of the chimeric gene in S. cerevisiae has substrate binding capability and hydrolyses insoluble starch, properties not present in the original yeast enzyme.
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Affiliation(s)
- Lorena Latorre-García
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Apartado de Correos (CSIC) 73, E46100-Burjassot (Valencia), Spain, Paterna, Valencia, Spain
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Current awareness on yeast. Yeast 2003; 20:455-62. [PMID: 12728936 DOI: 10.1002/yea.943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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