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Tsai SL, Sun Q, Chen W. Advances in consolidated bioprocessing using synthetic cellulosomes. Curr Opin Biotechnol 2022; 78:102840. [PMID: 36356377 DOI: 10.1016/j.copbio.2022.102840] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/02/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022]
Abstract
The primary obstacle impeding the more widespread use of biomass for energy and chemical production is the absence of a low-cost technology for overcoming their recalcitrant nature. It has been shown that the overall cost can be reduced by using a 'consolidated' bioprocessing (CBP) approach, in which enzyme production, biomass hydrolysis, and sugar fermentation can be combined. Cellulosomes are enzyme complexes found in many anaerobic microorganisms that are highly efficient for biomass depolymerization. While initial efforts to display synthetic cellulosomes have been successful, the overall conversion is still low for practical use. This limitation has been partially alleviated by displaying more complex cellulsome structures either via adaptive assembly or by using synthetic consortia. Since synthetic cellulosome nanostructures have also been created using either protein nanoparticles or DNA as a scaffold, there is the potential to tether these nanostructures onto living cells in order to further enhance the overall efficiency.
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Affiliation(s)
- Shen-Long Tsai
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei City 106335, Taiwan
| | - Qing Sun
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA.
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Zou S, Jia Y, He Q, Zhang K, Ban R, Hong J, Zhang M. Comparison of the Unfolded Protein Response in Cellobiose Utilization of Recombinant Angel- and W303-1A-Derived Yeast Expressing β-Glucosidase. Front Bioeng Biotechnol 2022; 10:837720. [PMID: 35433667 PMCID: PMC9008459 DOI: 10.3389/fbioe.2022.837720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
The unfolded protein response (UPR) is one of the most important protein quality control mechanisms in cells. At least, three factors are predicted to activate the UPR in yeast cells during fermentation. Using UPRE-lacZ as a reporter, we constructed two indicator strains, KZ and WZ, based on Angel-derived K-a and W303-1A strains, respectively, and investigated their UPR response to tunicamycin, ethanol, and acetic acid. Then, four strains carrying plasmids BG-cwp2 and BG were obtained to realize the displaying and secretion of β-glucosidase, respectively. The results of cellobiose utilization assays indicated interactions between the UPR and the metabolic burden between the strain source, anchoring moiety, oxygen supply, and cellobiose concentration. Meanwhile, as expected, growth (OD600), β-glucosidase, and β-galactosidase activities were shown to have a positive inter-relationship, in which the values of the KZ-derived strains were far lower than those of the WZ-derived strains. Additionally, extra metabolic burden by displaying over secreting was also much more serious in strain KZ than in strain WZ. The maximum ethanol titer of the four strains (KZ (BG-cwp2), KZ (BG), WZ (BG-cwp2), and WZ (BG)) in oxygen-limited 10% cellobiose fermentation was 3.173, 5.307, 5.495, and 5.486% (v/v), respectively, and the acetic acid titer ranged from 0.038 to 0.060% (v/v). The corresponding maximum values of the ratio of β-galactosidase activity to that of the control were 3.30, 5.29, 6.45, and 8.72, respectively. Under aerobic conditions with 2% cellobiose, those values were 3.79, 4.97, 6.99, and 7.67, respectively. A comparison of the results implied that β-glucosidase expression durably induced the UPR, and the effect of ethanol and acetic acid depended on the titer produced. Further study is necessary to identify ethanol- or acid-specific target gene expression. Taken together, our results indicated that the host strain W303-1A is a better secretory protein producer, and the first step to modify strain K-a for cellulosic ethanol fermentation would be to relieve the bottleneck of UPR capacity. The results of the present study will help to identify candidate host strains and optimize expression and fermentation by quantifying UPR induction.
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Affiliation(s)
- Shaolan Zou
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Key Laboratory for Green Chemical Technology of Ministry of Education, Tianjin University, Tianjin, China
- *Correspondence: Shaolan Zou, ; Jiefang Hong,
| | - Yudie Jia
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Qing He
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Kun Zhang
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, China
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Rui Ban
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Jiefang Hong
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Key Laboratory for Green Chemical Technology of Ministry of Education, Tianjin University, Tianjin, China
- *Correspondence: Shaolan Zou, ; Jiefang Hong,
| | - Minhua Zhang
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Key Laboratory for Green Chemical Technology of Ministry of Education, Tianjin University, Tianjin, China
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Cellulosic Ethanol Production Using a Dual Functional Novel Yeast. Int J Microbiol 2022; 2022:7853935. [PMID: 35295685 PMCID: PMC8920679 DOI: 10.1155/2022/7853935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/07/2022] [Accepted: 02/14/2022] [Indexed: 11/18/2022] Open
Abstract
Reducing the cost of cellulosic ethanol production, especially for cellulose hydrolytic enzymes, is vital to growing a sustainable and efficient cellulosic ethanol industry and bio-based economy. Using an ethanologenic yeast able to produce hydrolytic enzymes, such as Clavispora NRRL Y-50464, is one solution. NRRL Y-50464 is fast-growing and robust, and tolerates inhibitory compounds 2-furaldehyde (furfural) and 5-hydroxymethyl-2-furaldehyde (HMF) associated with lignocellulose-to-fuel conversion. It produces three forms of β-glucosidase isozymes, BGL1, BGL2, and BGL3, and ferment cellobiose as the sole carbon source. These β-glucosidases exhibited desirable enzyme kinetic parameters and high levels of enzyme-specific activity toward cellobiose and many oligosaccharide substrates. They tolerate the product inhibition of glucose and ethanol, and are stable to temperature and pH conditions. These characteristics are desirable for more efficient cellulosic ethanol production by simultaneous saccharification and fermentation. NRRL Y-50464 provided the highest cellulosic ethanol titers and conversion rates at lower cellulase loadings, using either pure cellulose or agricultural residues, as so far reported in the literature. This review summarizes NRRL Y-50464 performance on cellulosic ethanol production from refined cellulose, rice straw, and corn stover processed in various ways, in the presence or absence of furfural and HMF. This dual functional yeast has potential to serve as a prototype for the development of next-generation biocatalysts. Perspectives on continued strain development and process engineering improvements for more efficient cellulosic ethanol production from lignocellulosic materials are also discussed.
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Sharma J, Kumar V, Prasad R, Gaur NA. Engineering of Saccharomyces cerevisiae as a consolidated bioprocessing host to produce cellulosic ethanol: Recent advancements and current challenges. Biotechnol Adv 2022; 56:107925. [DOI: 10.1016/j.biotechadv.2022.107925] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/24/2022] [Accepted: 02/06/2022] [Indexed: 01/01/2023]
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Consolidated Bioprocessing: Synthetic Biology Routes to Fuels and Fine Chemicals. Microorganisms 2021; 9:microorganisms9051079. [PMID: 34069865 PMCID: PMC8157379 DOI: 10.3390/microorganisms9051079] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/27/2021] [Accepted: 05/14/2021] [Indexed: 11/17/2022] Open
Abstract
The long road from emerging biotechnologies to commercial “green” biosynthetic routes for chemical production relies in part on efficient microbial use of sustainable and renewable waste biomass feedstocks. One solution is to apply the consolidated bioprocessing approach, whereby microorganisms convert lignocellulose waste into advanced fuels and other chemicals. As lignocellulose is a highly complex network of polymers, enzymatic degradation or “saccharification” requires a range of cellulolytic enzymes acting synergistically to release the abundant sugars contained within. Complications arise from the need for extracellular localisation of cellulolytic enzymes, whether they be free or cell-associated. This review highlights the current progress in the consolidated bioprocessing approach, whereby microbial chassis are engineered to grow on lignocellulose as sole carbon sources whilst generating commercially useful chemicals. Future perspectives in the emerging biofoundry approach with bacterial hosts are discussed, where solutions to existing bottlenecks could potentially be overcome though the application of high throughput and iterative Design-Build-Test-Learn methodologies. These rapid automated pathway building infrastructures could be adapted for addressing the challenges of increasing cellulolytic capabilities of microorganisms to commercially viable levels.
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Zou S, Sun S, Zhang X, Li J, Guo J, Hong J, Ma Y, Zhang M. Repetitive δ-integration of a cellulase-encoding gene into the chromosome of an industrial Angel Yeast-derived strain by URA3 recycling. Biotechnol Appl Biochem 2020; 68:953-963. [PMID: 32658331 DOI: 10.1002/bab.1984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/25/2020] [Indexed: 11/07/2022]
Abstract
Genetic modification of industrial yeast strains often faces more difficulties than that of laboratory strains. Thus, new approaches are still required. In this research, the Angel Yeast-derived haploid strain Kα was genetically modified by multiple rounds of δ-integration, which was achieved via URA3 recycling. Three δ-integrative plasmids, pGδRU, pGδRU-BGL, and pGδRU-EG, were first constructed with two 167 bp δ sequences and a repeat-URA3-repeat fragment. Then, the δ-integrative strains containing the bgl1 or egl2 gene were successfully obtained by one-time transformation of the linearized pGδRU-BGL or pGδRU-EG fragment, respectively. Their counterparts in which the URA3 gene was looped out were also easily isolated by selection for growth on 5´-fluoroorotic acid plates, although the ratio of colonies lacking URA3 to the total number of colonies decreased with increasing copy number of the corresponding integrated cellulase-encoding gene. Similar results were observed during the second round of δ-integration, in which the δ-integration strain Kα(δ::bgl1-repeat) obtained from the first round was transformed with a linearized pGδRU-EG fragment. After 10 rounds of cell growth and transfer to fresh medium, the doubling times and enzyme activities of Kα(δ::bgl1-repeat), Kα(δ::egl2-repeat), and Kα(δ::bgl1-repeat)(δ::egl2-repeat) showed no significant change and were stable. Further, their maximum ethanol concentrations during simultaneous saccharification and fermentation of pretreated corncob over a 7-day period were 46.35, 33.13, and 51.77 g/L, respectively, which were all substantially higher than the parent Kα strain. Thus, repetitive δ-integration with URA3 recycling can be a feasible and valuable method for genetic engineering of Angel Yeast. These results also provide clues about some important issues related to δ-integration, such as the structural stability of δ-integrated genes and the effects of individual integration-site locations on gene expression. Further be elucidation of these issues should help to fully realize the potential of δ-integration-based methods in industrial yeast breeding.
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Affiliation(s)
- Shaolan Zou
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China
| | - Sifan Sun
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China
| | - Xiaomao Zhang
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China
| | - Jiaman Li
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China
| | - Jinghan Guo
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China
| | - Jiefang Hong
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
| | - Yuanyuan Ma
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
| | - Minhua Zhang
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, People's Republic of China
- Key Laboratory for Green Chemical Technology of Ministry of Education, R&D Center for Petrochemical Technology, Tianjin University, Tianjin, People's Republic of China
- State Key Laboratory of Engine, Tianjin University, Tianjin, People's Republic of China
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Singhvi MS, Gokhale DV. Lignocellulosic biomass: Hurdles and challenges in its valorization. Appl Microbiol Biotechnol 2019; 103:9305-9320. [DOI: 10.1007/s00253-019-10212-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 10/17/2019] [Accepted: 10/20/2019] [Indexed: 12/13/2022]
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Liu H, Sun J, Chang JS, Shukla P. Engineering microbes for direct fermentation of cellulose to bioethanol. Crit Rev Biotechnol 2018; 38:1089-1105. [DOI: 10.1080/07388551.2018.1452891] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Hao Liu
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China
| | - Jianliang Sun
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China
| | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan, China
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
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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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Amores GR, Guazzaroni ME, Arruda LM, Silva-Rocha R. Recent Progress on Systems and Synthetic Biology Approaches to Engineer Fungi As Microbial Cell Factories. Curr Genomics 2016; 17:85-98. [PMID: 27226765 PMCID: PMC4864837 DOI: 10.2174/1389202917666151116212255] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/23/2015] [Accepted: 06/01/2015] [Indexed: 01/03/2023] Open
Abstract
Filamentous fungi are remarkable organisms naturally specialized in deconstructing plant
biomass and this feature has a tremendous potential for biofuel production from renewable sources.
The past decades have been marked by a remarkable progress in the genetic engineering of fungi to
generate industry-compatible strains needed for some biotech applications. In this sense, progress in
this field has been marked by the utilization of high-throughput techniques to gain deep understanding
of the molecular machinery controlling the physiology of these organisms, starting thus the Systems
Biology era of fungi. Additionally, genetic engineering has been extensively applied to modify wellcharacterized
promoters in order to construct new expression systems with enhanced performance under the conditions of
interest. In this review, we discuss some aspects related to significant progress in the understating and engineering of
fungi for biotechnological applications, with special focus on the construction of synthetic promoters and circuits in organisms
relevant for industry. Different engineering approaches are shown, and their potential and limitations for the construction
of complex synthetic circuits in these organisms are examined. Finally, we discuss the impact of engineered
promoter architecture in the single-cell behavior of the system, an often-neglected relationship with a tremendous impact
in the final performance of the process of interest. We expect to provide here some new directions to drive future research
directed to the construction of high-performance, engineered fungal strains working as microbial cell factories.
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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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Two New Native β-Glucosidases from Clavispora NRRL Y-50464 Confer Its Dual Function as Cellobiose Fermenting Ethanologenic Yeast. PLoS One 2016; 11:e0151293. [PMID: 27011316 PMCID: PMC4806929 DOI: 10.1371/journal.pone.0151293] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/25/2016] [Indexed: 11/19/2022] Open
Abstract
Yeast strain Clavispora NRRL Y-50464 is able to produce cellulosic ethanol from lignocellulosic materials without addition of external β-glucosidase by simultaneous saccharification and fermentation. A β-glucosidase BGL1 protein from this strain was recently reported supporting its cellobiose utilization capability. Here, we report two additional new β-glucosidase genes encoding enzymes designated as BGL2 and BGL3 from strain NRRL Y-50464. Quantitative gene expression was analyzed and the gene function of BGL2 and BGL3 was confirmed by heterologous expression using cellobiose as a sole carbon source. Each gene was cloned and partially purified protein obtained separately for direct enzyme assay using varied substrates. Both proteins showed the highest specific activity at pH 5 and relatively strong affinity with a Km of 0.08 and 0.18 mM for BGL2 and BGL3, respectively. The optimum temperature was found to be 50°C for BGL2 and 55°C for BGL3. Both proteins were able to hydrolyze 1,4 oligosaccharides evaluated in this study. They also showed a strong resistance to glucose product inhibition with a Ki of 61.97 and 38.33 mM for BGL2 and BGL3, respectively. While BGL3 was sensitive showing a significantly reduced activity to 4% ethanol, BGL2 demonstrated tolerance to ethanol. Its activity was enhanced in the presence of ethanol but reduced at concentrations greater than 16%. The presence of the fermentation inhibitors furfural and HMF did not affect the enzyme activity. Our results suggest that a β-glucosidase gene family exists in Clavispora NRRL Y-50464 with at least three members in this group that validate its cellobiose hydrolysis functions for lower-cost cellulosic ethanol production. Results of this study confirmed the cellobiose hydrolysis function of strain NRRL Y-50464, and further supported this dual functional yeast as a candidate for lower-cost cellulosic ethanol production and next-generation biocatalyst development in potential industrial applications.
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Ali SS, Nugent B, Mullins E, Doohan FM. Fungal-mediated consolidated bioprocessing: the potential of Fusarium oxysporum for the lignocellulosic ethanol industry. AMB Express 2016; 6:13. [PMID: 26888202 PMCID: PMC4757592 DOI: 10.1186/s13568-016-0185-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 02/09/2016] [Indexed: 12/21/2022] Open
Abstract
Microbial bioprocessing of lignocellulose to bioethanol still poses challenges in terms of substrate catabolism. The most important challenge is to overcome substrate recalcitrance and to thus reduce the number of steps needed to biorefine lignocellulose. Conventionally, conversion involves chemical pretreatment of lignocellulose, followed by hydrolysis of biomass to monomer sugars that are subsequently fermented into bioethanol. Consolidated bioprocessing (CBP) has been suggested as an efficient and economical method of manufacturing bioethanol from lignocellulose. CBP integrates the hydrolysis and fermentation steps into a single process, thereby significantly reducing the amount of steps in the biorefining process. Filamentous fungi are remarkable organisms that are naturally specialised in deconstructing plant biomass and thus they have tremendous potential as components of CBP. The fungus Fusarium oxysporum has potential for CBP of lignocellulose to bioethanol. Here we discuss the complexity and potential of CBP, the bottlenecks in the process, and the potential influence of fungal genetic diversity, substrate complexity and new technologies on the efficacy of CPB of lignocellulose, with a focus on F. oxysporum.
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Kavšček M, Stražar M, Curk T, Natter K, Petrovič U. Yeast as a cell factory: current state and perspectives. Microb Cell Fact 2015; 14:94. [PMID: 26122609 PMCID: PMC4486425 DOI: 10.1186/s12934-015-0281-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/11/2015] [Indexed: 02/06/2023] Open
Abstract
The yeast Saccharomyces cerevisiae is one of the oldest and most frequently used microorganisms in biotechnology with successful applications in the production of both bulk and fine chemicals. Yet, yeast researchers are faced with the challenge to further its transition from the old workhorse to a modern cell factory, fulfilling the requirements for next generation bioprocesses. Many of the principles and tools that are applied for this development originate from the field of synthetic biology and the engineered strains will indeed be synthetic organisms. We provide an overview of the most important aspects of this transition and highlight achievements in recent years as well as trends in which yeast currently lags behind. These aspects include: the enhancement of the substrate spectrum of yeast, with the focus on the efficient utilization of renewable feedstocks, the enhancement of the product spectrum through generation of independent circuits for the maintenance of redox balances and biosynthesis of common carbon building blocks, the requirement for accurate pathway control with improved genome editing and through orthogonal promoters, and improvement of the tolerance of yeast for specific stress conditions. The causative genetic elements for the required traits of the future yeast cell factories will be assembled into genetic modules for fast transfer between strains. These developments will benefit from progress in bio-computational methods, which allow for the integration of different kinds of data sets and algorithms, and from rapid advancement in genome editing, which will enable multiplexed targeted integration of whole heterologous pathways. The overall goal will be to provide a collection of modules and circuits that work independently and can be combined at will, depending on the individual conditions, and will result in an optimal synthetic host for a given production process.
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Affiliation(s)
- Martin Kavšček
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010, Graz, Austria.
| | - Martin Stražar
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
| | - Tomaž Curk
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
| | - Klaus Natter
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010, Graz, Austria.
| | - Uroš Petrovič
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.
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