1
|
Zhao C, Zhao J, Han J, Mei Y, Fang H. Improved consolidated bioprocessing for itaconic acid production by simultaneous optimization of cellulase and metabolic pathway of Neurospora crassa. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:57. [PMID: 38685114 PMCID: PMC11059683 DOI: 10.1186/s13068-024-02505-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/20/2024] [Indexed: 05/02/2024]
Abstract
Lignocellulose was directly used in itaconic acid production by a model filamentous fungus Neurospora crassa. The promoters of two clock control genes and cellobiohydrolase 1 gene were selected for heterologous genes expression by evaluating different types of promoters. The effect of overexpression of different cellulase was compared, and it was found that expression of cellobiohydrolase 2 from Trichoderma reesei increased the filter paper activity by 2 times, the cellobiohydrolase activity by 4.5 times, and that the itaconic acid titer was also significantly improved. A bidirectional cis-aconitic acid accumulation strategy was established by constructing the reverse glyoxylate shunt and expressing the transporter MTTA, which increased itaconic acid production to 637.2 mg/L. The simultaneous optimization of cellulase and metabolic pathway was more conducive to the improvement of cellulase activity than that of cellulase alone, so as to further increase itaconic acid production. Finally, through the combination of fermentation by optimized strains and medium optimization, the titers of itaconic acid using Avicel and corn stover as substrate were 1165.1 mg/L and 871.3 mg/L, respectively. The results prove the potential of the consolidated bioprocessing that directly converts lignocellulose to itaconic acid by a model cellulase synthesizing strain.
Collapse
Affiliation(s)
- Chen Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China.
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - Jiajia Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
- The Second Department of Vaccine, Lanzhou Institute of Biological Products Co., Ltd., Lanzhou, 730046, China
| | - Jingjing Han
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yaojie Mei
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Hao Fang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, 733 Jianshe 3rd Road, Hangzhou, 311200, Zhejiang, China.
| |
Collapse
|
2
|
Jia J, Tan Y, Gao J, Han J, Shi P, Fang H, Zhao C. Cloning and expression of Neurospora crassa cellobiohydrolase II in Pichia pastoris. Protein Expr Purif 2024; 216:106416. [PMID: 38104790 DOI: 10.1016/j.pep.2023.106416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/19/2023]
Abstract
A major cellobiohydrolase of Neurospora crassa CBH2 was successfully expressed in Pichia pastoris. The maximum Avicelase activity in shake flask among seven transformants which selected on 4.0 g/L G418 plates was 0.61 U/mL. The optimal pH and temperature for Avicelase activity of the recombinant CBH2 were determined to be 4.8 and 60 °C, respectively. The new CBH2 maintained 63.5 % Avicelase activity in the range of pH 4.0-10.4, and 60.2 % Avicelase activity in the range of 30-90 °C. After incubation at 70-90 °C for 1 h, the Avicelase activity retained 60.5 % of its initial activity. The presence of Zn2+, Ca2+ or Cd2+ enhanced the Avicelase activity of the CBH2, of which Cd2+ at 10 mM causing the highest increase. The recombinant CBH2 was used to enhance the Avicel hydrolysis by improving the exo-exo-synergism between CBH2 and CBH1 in N.crassa cellulase. The enzymatic hydrolysis yield was increased by 38.1 % by adding recombinant CBH2 and CBH1, and the yield was increased by 215.4 % when the temperature is raised to 70 °C. This work provided a CBH2 with broader pH range and better heat resistance, which is a potential enzyme candidate in food, textile, pulp and paper industries, and other industrial fields.
Collapse
Affiliation(s)
- Jingsong Jia
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Yu Tan
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Jialun Gao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Jingjing Han
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Peng Shi
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Hao Fang
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chen Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China.
| |
Collapse
|
3
|
Characterization of a GH5 endoxylanase from Penicillium funiculosum and its synergism with GH16 endo-1,3(4)-glucanase in saccharification of sugarcane bagasse. Sci Rep 2022; 12:17219. [PMID: 36241677 PMCID: PMC9568505 DOI: 10.1038/s41598-022-21529-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/28/2022] [Indexed: 01/06/2023] Open
Abstract
The production of second-generation fuels from lignocellulosic residues such as sugarcane bagasse (SCB) requires the synergistic interaction of key cellulose-degrading enzymes and accessory proteins for their complete deconstruction to useful monomeric sugars. Here, we recombinantly expressed and characterized unknown GH5 xylanase from P. funiculosum (PfXyn5) in Pichia pastoris, which was earlier found in our study to be highly implicated in SCB saccharification. The PfXyn5 has a molecular mass of ~ 55 kDa and showed broad activity against a range of substrates like xylan, xyloglucan, laminarin and p-nitrophenyl-β-D-xylopyranoside, with the highest specific activity of 0.7 U/mg against xylan at pH 4.5 and 50 °C. Analysis of the degradation products of xylan and SCB by PfXyn5 showed significant production of xylooligosaccharides (XOS) with a degree of polymerization (DP) ranging from two (DP2) to six (DP6), thus, suggesting that the PfXyn5 is an endo-acting enzyme. The enzyme synergistically improved the saccharification of SCB when combined with the crude cellulase cocktail of P. funiculosum with a degree of synergism up to 1.32. The PfXyn5 was further expressed individually and simultaneously with a notable GH16 endoglucanase (PfEgl16) in a catabolite-derepressed strain of P. funiculosum, PfMig188, and the saccharification efficiency of the secretomes from the resulting transformants were investigated on SCB. The secretome of PfMig188 overexpressing Xyn5 or Egl16 increased the saccharification of SCB by 9% or 7%, respectively, over the secretome of PfMig188, while the secretome of dual transformant increased SCB saccharification by ~ 15% at the same minimal protein concentration.
Collapse
|
4
|
Fang H, Deng Y, Pan Y, Li C, Yu L. Distributive and collaborative push‐and‐pull in an artificial microbial consortium for improved consolidated bioprocessing. AIChE J 2022. [DOI: 10.1002/aic.17844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Hao Fang
- ZJU‐Hangzhou Global Scientific and Technological Innovation Center, No.733 Jianshe San Road Hangzhou Zhejiang China
- College of Life Sciences, Northwest A&F University, No.22 Xinong Road Yangling Shaanxi China
- College of Chemical and Biological Engineering, Zhejiang University, No.38 Zheda Road Hangzhou Zhejiang China
| | - Yuntao Deng
- College of Life Sciences, Northwest A&F University, No.22 Xinong Road Yangling Shaanxi China
| | - Yingjie Pan
- ZJU‐Hangzhou Global Scientific and Technological Innovation Center, No.733 Jianshe San Road Hangzhou Zhejiang China
| | - Chaofeng Li
- College of Life Sciences, Northwest A&F University, No.22 Xinong Road Yangling Shaanxi China
| | - Liang Yu
- Department of Biological Systems Engineering Washington State University Pullman Washington United States of America
| |
Collapse
|
5
|
Promoter regulation and genetic engineering strategies for enhanced cellulase expression in Trichoderma reesei. Microbiol Res 2022; 259:127011. [DOI: 10.1016/j.micres.2022.127011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 01/18/2023]
|
6
|
Wang Y, Liu R, Liu H, Li X, Shen L, Zhang W, Song X, Liu W, Liu X, Zhong Y. Development of a powerful synthetic hybrid promoter to improve the cellulase system of Trichoderma reesei for efficient saccharification of corncob residues. Microb Cell Fact 2022; 21:5. [PMID: 34983541 PMCID: PMC8725555 DOI: 10.1186/s12934-021-01727-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 12/17/2021] [Indexed: 02/07/2023] Open
Abstract
Background The filamentous fungus Trichoderma reesei is a widely used workhorse for cellulase production in industry due to its prominent secretion capacity of extracellular cellulolytic enzymes. However, some key components are not always sufficient in this cellulase cocktail, making the conversion of cellulose-based biomass costly on the industrial scale. Development of strong and efficient promoters would enable cellulase cocktail to be optimized for bioconversion of biomass. Results In this study, a synthetic hybrid promoter was constructed and applied to optimize the cellulolytic system of T. reesei for efficient saccharification towards corncob residues. Firstly, a series of 5’ truncated promoters in different lengths were established based on the strong constitutive promoter Pcdna1. The strongest promoter amongst them was Pcdna1-3 (− 640 to − 1 bp upstream of the translation initiation codon ATG), exhibiting a 1.4-fold higher activity than that of the native cdna1 promoter. Meanwhile, the activation region (− 821 to − 622 bp upstream of the translation initiation codon ATG and devoid of the Cre1-binding sites) of the strong inducible promoter Pcbh1 was cloned and identified to be an amplifier in initiating gene expression. Finally, this activation region was fused to the strongest promoter Pcdna1-3, generating the novel synthetic hybrid promoter Pcc. This engineered promoter Pcc drove strong gene expression by displaying 1.6- and 1.8-fold stronger fluorescence intensity than Pcbh1 and Pcdna1 under the inducible condition using egfp as the reporter gene, respectively. Furthermore, Pcc was applied to overexpress the Aspergillus niger β-glucosidase BGLA coding gene bglA and the native endoglucanase EG2 coding gene eg2, achieving 43.5-fold BGL activity and 1.2-fold EG activity increase, respectively. Ultimately, to overcome the defects of the native cellulase system in T. reesei, the bglA and eg2 were co-overexpressed under the control of Pcc promoter. The bglA-eg2 double expression strain QPEB70 exhibited a 178% increase in total cellulase activity, whose cellulase system displayed 2.3- and 2.4-fold higher saccharification efficiency towards acid-pretreated and delignified corncob residues than the parental strain, respectively. Conclusions The synthetic hybrid promoter Pcc was generated and employed to improve the cellulase system of T. reesei by expressing specific components. Therefore, construction of synthetic hybrid promoters would allow particular cellulase genes to be expressed at desired levels, which is a viable strategy to optimize the cellulolytic enzyme system for efficient biomass bioconversion. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01727-8.
Collapse
Affiliation(s)
- Yifan Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Ruiyan Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Hong Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Xihai Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Linjing Shen
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Weican Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Xin Song
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Xiangmei Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
| |
Collapse
|
7
|
Madhavan A, Arun KB, Sindhu R, Alphonsa Jose A, Pugazhendhi A, Binod P, Sirohi R, Reshmy R, Kumar Awasthi M. Engineering interventions in industrial filamentous fungal cell factories for biomass valorization. BIORESOURCE TECHNOLOGY 2022; 344:126209. [PMID: 34715339 DOI: 10.1016/j.biortech.2021.126209] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 05/15/2023]
Abstract
Filamentous fungi possess versatile capabilities for synthesizing a variety of valuable bio compounds, including enzymes, organic acids and small molecule secondary metabolites. The advancements of genetic and metabolic engineering techniques and the availability of sequenced genomes discovered their potential as expression hosts for recombinant protein production. Remarkably, plant-biomass degrading filamentous fungi show the unique capability to decompose lignocellulose, an extremely recalcitrant biopolymer. The basic biochemical approaches have motivated several industrial processes for lignocellulose biomass valorisation into fermentable sugars and other biochemical for biofuels, biomolecules, and biomaterials. The review gives insight into current trends in engineering filamentous fungi for enzymes, fuels, and chemicals from lignocellulose biomass. This review describes the variety of enzymes and compounds that filamentous fungi produce, engineering of filamentous fungi for biomass valorisation with a special focus on lignocellulolytic enzymes and other bulk chemicals.
Collapse
Affiliation(s)
- Aravind Madhavan
- Rajiv Gandhi Centre for Biotechnology, Jagathy, Trivandrum 695 014, India.
| | - K B Arun
- Rajiv Gandhi Centre for Biotechnology, Jagathy, Trivandrum 695 014, India
| | - Raveendran Sindhu
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | - Anju Alphonsa Jose
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | | | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | - Ranjna Sirohi
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea; Centre for Energy & Environmental Sustainability, Lucknow 226001. Uttar Pradesh, India
| | - R Reshmy
- Post Graduate and Research Department of Chemistry, Bishop Moore College, Mavelikara 690 110, Kerala, India
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712 100, PR China
| |
Collapse
|
8
|
Fang H, Li C, Zhao J, Zhao C. Biotechnological Advances and Trends in Engineering Trichoderma reesei towards Cellulase Hyperproducer. BIOTECHNOL BIOPROC E 2021. [DOI: 10.1007/s12257-020-0243-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
9
|
Li C, Lin X, Ling X, Li S, Fang H. Consolidated bioprocessing of lignocellulose for production of glucaric acid by an artificial microbial consortium. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:110. [PMID: 33931115 PMCID: PMC8086319 DOI: 10.1186/s13068-021-01961-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND The biomanufacturing of D-glucaric acid has attracted increasing interest because it is one of the top value-added chemicals produced from biomass. Saccharomyces cerevisiae is regarded as an excellent host for D-glucaric acid production. RESULTS The opi1 gene was knocked out because of its negative regulation on myo-inositol synthesis, which is the limiting step of D-glucaric acid production by S. cerevisiae. We then constructed the biosynthesis pathway of D-glucaric acid in S. cerevisiae INVSc1 opi1Δ and obtained two engineered strains, LGA-1 and LGA-C, producing record-breaking titers of D-glucaric acid: 9.53 ± 0.46 g/L and 11.21 ± 0.63 g/L D-glucaric acid from 30 g/L glucose and 10.8 g/L myo-inositol in fed-batch fermentation mode, respectively. However, LGA-1 was preferable because of its genetic stability and its superior performance in practical applications. There have been no reports on D-glucaric acid production from lignocellulose. Therefore, the biorefinery processes, including separated hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF) and consolidated bioprocessing (CBP) were investigated and compared. CBP using an artificial microbial consortium composed of Trichoderma reesei (T. reesei) Rut-C30 and S. cerevisiae LGA-1 was found to have relatively high D-glucaric acid titers and yields after 7 d of fermentation, 0.54 ± 0.12 g/L D-glucaric acid from 15 g/L Avicel and 0.45 ± 0.06 g/L D-glucaric acid from 15 g/L steam-exploded corn stover (SECS), respectively. In an attempt to design the microbial consortium for more efficient CBP, the team consisting of T. reesei Rut-C30 and S. cerevisiae LGA-1 was found to be the best, with excellent work distribution and collaboration. CONCLUSIONS Two engineered S. cerevisiae strains, LGA-1 and LGA-C, with high titers of D-glucaric acid were obtained. This indicated that S. cerevisiae INVSc1 is an excellent host for D-glucaric acid production. Lignocellulose is a preferable substrate over myo-inositol. SHF, SSF, and CBP were studied, and CBP using an artificial microbial consortium of T. reesei Rut-C30 and S. cerevisiae LGA-1 was found to be promising because of its relatively high titer and yield. T. reesei Rut-C30 and S. cerevisiae LGA-1were proven to be the best teammates for CBP. Further work should be done to improve the efficiency of this microbial consortium for D-glucaric acid production from lignocellulose.
Collapse
Affiliation(s)
- Chaofeng Li
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Xianyang, 712100, Shaanxi, China
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, Xianyang, 712100, Shaanxi, China
| | - Xiaofeng Lin
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Xianyang, 712100, Shaanxi, China
| | - Xing Ling
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Xianyang, 712100, Shaanxi, China
| | - Shuo Li
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Xianyang, 712100, Shaanxi, China
| | - Hao Fang
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Xianyang, 712100, Shaanxi, China.
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, Xianyang, 712100, Shaanxi, China.
| |
Collapse
|
10
|
Kant Bhatia S, Vivek N, Kumar V, Chandel N, Thakur M, Kumar D, Yang YH, Pugazendhi A, Kumar G. Molecular biology interventions for activity improvement and production of industrial enzymes. BIORESOURCE TECHNOLOGY 2021; 324:124596. [PMID: 33440311 DOI: 10.1016/j.biortech.2020.124596] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
Metagenomics and directed evolution technology have brought a revolution in search of novel enzymes from extreme environment and improvement of existing enzymes and tuning them towards certain desired properties. Using advanced tools of molecular biology i.e. next generation sequencing, site directed mutagenesis, fusion protein, surface display, etc. now researchers can engineer enzymes for improved activity, stability, and substrate specificity to meet the industrial demand. Although many enzymatic processes have been developed up to industrial scale, still there is a need to overcome limitations of maintaining activity during the catalytic process. In this article recent developments in enzymes industrial applications and advancements in metabolic engineering approaches to improve enzymes efficacy and production are reviewed.
Collapse
Affiliation(s)
- Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea; Institute for Ubiquitous Information Technology and Application, Konkuk University, Seoul 05029, Republic of Korea
| | - Narisetty Vivek
- Centre for Climate and Environmental Protection, School of Water, Energy and Environment, Cranfield University, Cranfield MK43 0AL, UK
| | - Vinod Kumar
- Centre for Climate and Environmental Protection, School of Water, Energy and Environment, Cranfield University, Cranfield MK43 0AL, UK
| | - Neha Chandel
- School of Medical and Allied Sciences, GD Goenka University, Gurugram 122103, Haryana, India
| | - Meenu Thakur
- Department of Biotechnology, Shoolini Institute of Life Sciences and Business Management, Solan 173212, Himachal Pradesh, India
| | - Dinesh Kumar
- School of Bioengineering & Food Technology, Shoolini University of Biotechnology and Management Sciences, Solan 173229, Himachal Pradesh, India
| | - Yung-Hun Yang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea; Institute for Ubiquitous Information Technology and Application, Konkuk University, Seoul 05029, Republic of Korea
| | - Arivalagan Pugazendhi
- Innovative Green Product Synthesis and Renewable Environment Development Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho ChiMinh City, Viet Nam
| | - Gopalakrishnan Kumar
- Institute of Chemistry, Bioscience and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, Box 8600 Forus, 4036 Stavanger, Norway; School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| |
Collapse
|
11
|
Effects of the Transcription Factor Ace2 from Trichoderma reesei on Cellulase and Hemicellulase Expression in Trichoderma orientalis EU7-22. Appl Biochem Biotechnol 2021; 193:2098-2109. [PMID: 33608806 DOI: 10.1007/s12010-021-03529-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 02/08/2021] [Indexed: 10/22/2022]
Abstract
Trichoderma orientalis (T. orientalis) EU7-22 has a complete cellulase system and shows a remarkable enzyme activity with high potential in the industry. Ace2 is an important transcriptional factor for cellulase and hemicellulase expression in Trichoderma reesei (T. reesei). However, the ace2 gene cannot be found in the genome of T. orientalis. Researches show that the mechanism of cellulase transcriptional regulation in T. orientalis keeps high similarity with T. reesei up till now. So, in this study, the ace2 of Trichoderma reesei QM9414 was heterologous expressed in T. orientalis EU7-22. As a result, xylanase activity and β-glucosidase activity of ace2 heterogeneous expression strains are improved and total cellulase activity is decreased. The result of qPCR is in accordance with enzyme activities. This study provides a reference for an in-depth study on transcriptional regulation mechanisms of T. orientalis.
Collapse
|
12
|
Synergistic Action of a Lytic Polysaccharide Monooxygenase and a Cellobiohydrolase from Penicillium funiculosum in Cellulose Saccharification under High-Level Substrate Loading. Appl Environ Microbiol 2020; 86:AEM.01769-20. [PMID: 32978122 DOI: 10.1128/aem.01769-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/15/2020] [Indexed: 12/25/2022] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are crucial industrial enzymes required in the biorefinery industry as well as in the natural carbon cycle. These enzymes, known to catalyze the oxidative cleavage of glycosidic bonds, are produced by numerous bacterial and fungal species to assist in the degradation of cellulosic biomass. In this study, we annotated and performed structural analysis of an uncharacterized LPMO from Penicillium funiculosum (PfLPMO9) based on computational methods in an attempt to understand the behavior of this enzyme in biomass degradation. PfLPMO9 exhibited 75% and 36% sequence identities with LPMOs from Thermoascus aurantiacus (TaLPMO9A) and Lentinus similis (LsLPMO9A), respectively. Furthermore, multiple fungal genetic manipulation tools were employed to simultaneously overexpress LPMO and cellobiohydrolase I (CBH1) in a catabolite-derepressed strain of Penicillium funiculosum, PfMig188 (an engineered variant of P. funiculosum), to improve its saccharification performance toward acid-pretreated wheat straw (PWS) at 20% substrate loading. The resulting transformants showed improved LPMO and CBH1 expression at both the transcriptional and translational levels, with ∼200% and ∼66% increases in ascorbate-induced LPMO and Avicelase activities, respectively. While the secretome of PfMig88 overexpressing LPMO or CBH1 increased the saccharification of PWS by 6% or 13%, respectively, over the secretome of PfMig188 at the same protein concentration, the simultaneous overexpression of these two genes led to a 20% increase in saccharification efficiency over that observed with PfMig188, which accounted for 82% saccharification of PWS under 20% substrate loading.IMPORTANCE The enzymatic hydrolysis of cellulosic biomass by cellulases continues to be a significant bottleneck in the development of second-generation biobased industries. While increasing efforts are being made to obtain indigenous cellulases for biomass hydrolysis, the high production cost of this enzyme remains a crucial challenge affecting its wide availability for the efficient utilization of cellulosic materials. This is because it is challenging to obtain an enzymatic cocktail with balanced activity from a single host. This report describes the annotation and structural analysis of an uncharacterized lytic polysaccharide monooxygenase (LPMO) gene in Penicillium funiculosum and its impact on biomass deconstruction upon overexpression in a catabolite-derepressed strain of P. funiculosum Cellobiohydrolase I (CBH1), which is the most important enzyme produced by many cellulolytic fungi for the saccharification of crystalline cellulose, was further overexpressed simultaneously with LPMO. The resulting secretome was analyzed for enhanced LPMO and exocellulase activities and the corresponding improvement in saccharification performance (by ∼20%) under high-level substrate loading using a minimal amount of protein.
Collapse
|
13
|
Cai L, Xu S, Lu T, Lin D, Yao S. Salt-tolerant mechanism of marine Aspergillus niger cellulase cocktail and improvement of its activity. Chin J Chem Eng 2020. [DOI: 10.1016/j.cjche.2019.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
14
|
Han H, Ling Z, Khan A, Virk AK, Kulshrestha S, Li X. Improvements of thermophilic enzymes: From genetic modifications to applications. BIORESOURCE TECHNOLOGY 2019; 279:350-361. [PMID: 30755321 DOI: 10.1016/j.biortech.2019.01.087] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/19/2019] [Accepted: 01/21/2019] [Indexed: 06/09/2023]
Abstract
Thermozymes (from thermophiles or hyperthermophiles) offer obvious advantages due to their excellent thermostability, broad pH adaptation, and hydrolysis ability, resulting in diverse industrial applications including food, paper, and textile processing, biofuel production. However, natural thermozymes with low yield and poor adaptability severely hinder their large-scale applications. Extensive studies demonstrated that using genetic modifications such as directed evolution, semi-rational design, and rational design, expression regulations and chemical modifications effectively improved enzyme's yield, thermostability and catalytic efficiency. However, mechanism-based techniques for thermozymes improvements and applications need more attention. In this review, stabilizing mechanisms of thermozymes are summarized for thermozymes improvements, and these improved thermozymes eventually have large-scale industrial applications.
Collapse
Affiliation(s)
- Huawen Han
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China
| | - Zhenmin Ling
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China
| | - Aman Khan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China
| | - Amanpreet Kaur Virk
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan, Himachal Pradesh 173229, India
| | - Saurabh Kulshrestha
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan, Himachal Pradesh 173229, India
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China.
| |
Collapse
|
15
|
Simultaneous enhancement of the beta-exo synergism and exo-exo synergism in Trichoderma reesei cellulase to increase the cellulose degrading capability. Microb Cell Fact 2019; 18:9. [PMID: 30657063 PMCID: PMC6337788 DOI: 10.1186/s12934-019-1060-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/10/2019] [Indexed: 11/18/2022] Open
Abstract
Background Cellulase is the one of the largest contributors to the high production costs of the lignocellulose-based biorefineries. As the most widely used cellulase producer, Trichoderma reesei has two weaknesses, deficiencies in β-glucosidase and cellobiohydrolase II. This work aimed at solving this problem by simultaneous enhancement of the beta–exo synergism and exo–exo synergism in T. reesei cellulase to increase the cellulose degrading capability, i.e. enhanced co-expression of the β-glucosidase gene the cellobiohydrolase II gene of T. reesei. Results Enhanced co-expression of the β-glucosidase gene and the cellobiohydrolase II gene in T. reesei using the strong promoter Pcbh1 was found successful in overcoming the two weaknesses. Filter paper activities of T. reesei cellulase were greatly elevated, which were 7.21 ± 0.45 (E7, Aabgl1 and Trcbh2) and 7.69 ± 0.42 (F6, Anbgl1 and Trcbh2) FPIU/mL. They were much higher than that of the parental strain Rut-C30, 2.45 ± 0.36 FPIU/mL. Enzymatic hydrolysis yields were also improved, from 67.22 ± 1.61% by Rut-C30 cellulase to 87.98 ± 0.65% by E7 cellulase and 86.50 ± 1.01% by F6 cellulase. The substrate loading for 1 g glucose release from SECS were decreased, from 2.9637 g SECS using Rut-C30 cellulase to 2.0291 g SECS using E7 cellulase and 2.0573 g SECS using F6 cellulase. As a result, the efficiency of the process from SECS to glucose was substantially improved. Conclusions Enhanced co-expression of the β-glucosidase gene and the cellobiohydrolase II gene in T. reesei using the strong promoter Pcbh1 in T. reesei was proven triumphal in the simultaneous enhancement of the beta–exo synergism and exo–exo synergism in T. reesei cellulase. This strategy also improved the cellulase production, enzymatic hydrolysis yield and the efficiency of the process from SECS to glucose in the context of on-site cellulase production. This work is a commendable attempt in the cellulase composition optimization at the transcriptional level.
Collapse
|
16
|
Consolidated bioprocessing of lignocellulosic biomass to itaconic acid by metabolically engineering Neurospora crassa. Appl Microbiol Biotechnol 2018; 102:9577-9584. [DOI: 10.1007/s00253-018-9362-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/13/2018] [Accepted: 09/03/2018] [Indexed: 12/18/2022]
|
17
|
Zhang J, Zhang G, Wang W, Wang W, Wei D. Enhanced cellulase production in Trichoderma reesei RUT C30 via constitution of minimal transcriptional activators. Microb Cell Fact 2018; 17:75. [PMID: 29773074 PMCID: PMC5956553 DOI: 10.1186/s12934-018-0926-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 05/11/2018] [Indexed: 01/06/2023] Open
Abstract
Background Cellulase can convert lignocellulosic feedstocks into fermentable sugars, which can be used for the industrial production of biofuels and chemicals. The high cost of cellulase production remains a challenge for lignocellulose breakdown. Trichoderma reesei RUT C30 serves as a well-known industrial workhorse for cellulase production. Therefore, the enhancement of cellulase production by T. reesei RUT C30 is of great importance. Results Two sets of novel minimal transcriptional activators (DBDace2-VP16 and DBDcre1-VP16) were designed and expressed in T. reesei RUT C30. Expression of DBDace2-VP16 and DBDcre1-VP16 improved cellulase production under induction (avicel or lactose) and repression (glucose) conditions, respectively. The strain TMTA66 under avicel and TMTA139 under glucose with the highest cellulase activities outperformed other transformants and the parental strain under the corresponding conditions. For TMTA66 strains, the highest FPase activity was approximately 1.3-fold greater than that of the parental strain RUT C30 at 120 h of cultivation in a shake flask using avicel as the sole carbon source. The FPase activity (U/mg biomass) in TMTA139 strains was approximately 26.5-fold higher than that of the parental strain RUT C30 at 72 h of cultivation in a shake flask using glucose as the sole carbon source. Furthermore, the crude enzymes produced in the 7-L fermenter from TMTA66 and TMTA139 supplemented with commercial β-glucosidase hydrolyzed pretreated corn stover effectively. Conclusions These results show that replacing natural transcription factors with minimal transcriptional activators is a powerful strategy to enhance cellulase production in T. reesei. Our current study also offers an alternative genetic engineering strategy for the enhanced production of industrial products by other fungi. Electronic supplementary material The online version of this article (10.1186/s12934-018-0926-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Jiajia Zhang
- State Key Lab of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 130 Meilong Road, P.O.B. 311, Shanghai, 200237, China
| | - Guoxiu Zhang
- State Key Lab of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 130 Meilong Road, P.O.B. 311, Shanghai, 200237, China
| | - Wei Wang
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Wei Wang
- State Key Lab of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 130 Meilong Road, P.O.B. 311, Shanghai, 200237, China.
| | - Dongzhi Wei
- State Key Lab of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, 130 Meilong Road, P.O.B. 311, Shanghai, 200237, China
| |
Collapse
|
18
|
Hernández C, Milagres AMF, Vázquez-Marrufo G, Muñoz-Páez KM, García-Pérez JA, Alarcón E. An ascomycota coculture in batch bioreactor is better than polycultures for cellulase production. Folia Microbiol (Praha) 2018; 63:467-478. [PMID: 29423709 DOI: 10.1007/s12223-018-0588-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/24/2018] [Indexed: 01/23/2023]
Abstract
Efficient hydrolysis of holocellulose depends on a proper balance between cellulase (endoglucanase, exoglucanase, β-glucosidase) and xylanase activities. The present study aimed to induce the production of cellulases and xylanases using liquid cultures (one, two, three, and four fungal strains on the same bioreactor) of wild strains of Trichoderma harzianum, Aspergillus niger, and Fusarium oxysporum. The strains were identified by amplification and analysis of the ITS rDNA region and the obtained sequences were deposited in Genbank. Enzymes (endoglucanase, exoglucansae, β-glucosidase, and xylanase activities) and the profile of extracellular protein isoforms (SDS-PAGE) produced by different fungal combinations (N = 14) were analyzed by Pearson's correlation matrix and principal component analysis (PCA). According to our results, induction of endoglucanase (19.02%) and β-glucosidase (6.35%) were obtained after 4 days when A. niger and F. oxysporum were cocultured. The combination of A. niger-T. harzianum produced higher endoglucanase in a shorter time than monocultures. On the contrary, when more than two strains were cultured in the same reactor, the relationships of competition were established, trending to diminish the amount of enzymes and the extracellular protein isoforms produced. The xylanase production was sensible to stress produced by mixed cultures, decreasing their activity. This is important when the aim is to produce cellulase-free xylanase. In addition, exoglucanase activity did not change in the combinations tested.
Collapse
Affiliation(s)
- Christian Hernández
- Instituto de Biotecnología y Ecología Aplicada (INBIOTECA), Universidad Veracruzana, Avenida de las culturas veracruzanas no. 101, colonia Emiliano Zapata, 91090, Xalapa, Veracruz, Mexico
| | - Adriane M F Milagres
- Departamento de Biotecnología, Escola de engenharia de Lorena (EEL), Universidade de São Paulo, Estrada Municipal do Campinho s/n - Pte Nova, Lorena, SP, 12602-810, Brazil
| | - Gerardo Vázquez-Marrufo
- Centro Multidisciplinario de Estudios en Biotecnología (CMEB), Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Calle Morelia-Zinapecuaro Km 9.5, colonia La Palma, 58262, Tarímbaro, Michoacán, Mexico
| | - Karla María Muñoz-Páez
- Laboratorio de Investigación en Procesos Avanzados de Tratamiento de Aguas, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, 76230, Querétaro, Mexico
| | - José Antonio García-Pérez
- Facultad de Biología, Universidad Veracruzana, Circuito Gonzalo Aguirre Beltrán, Zona Universitaria, 91090, Xalapa, Veracruz, Mexico
| | - Enrique Alarcón
- Instituto de Biotecnología y Ecología Aplicada (INBIOTECA), Universidad Veracruzana, Avenida de las culturas veracruzanas no. 101, colonia Emiliano Zapata, 91090, Xalapa, Veracruz, Mexico.
| |
Collapse
|
19
|
Li Z, Liu G, Qu Y. Improvement of cellulolytic enzyme production and performance by rational designing expression regulatory network and enzyme system composition. BIORESOURCE TECHNOLOGY 2017; 245:1718-1726. [PMID: 28684177 DOI: 10.1016/j.biortech.2017.06.120] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 06/07/2023]
Abstract
Filamentous fungi are considered as the most efficient producers expressing lignocellulose-degrading enzymes. Penicillium oxalicum strains possess extraordinary fungal lignocellulolytic enzyme systems and can efficiently utilize plant biomass. In recent years, the regulatory aspects of production of hydrolytic enzymes by P. oxalicum have been well established. This review aims to discuss the recent developments for the production of lignocellulolytic enzymes by P. oxalicum. The main cellulolytic transcription factors mediating the complex transcriptional-regulatory network are highlighted. The genome-wide identification of cellulolytic transcription factors, the cascade regulation network for cellulolytic gene expression, and the synergistic and dose-controlled regulation by cellulolytic regulators are discussed. A cellulase regulatory network sensitive to inducers in intracellular environments, the cross-talk of regulation of lignocellulose-degrading enzyme and amylase, and accessory enzymes are also demonstrated. Finally, strategies for the metabolic engineering of P. oxalicum, which show promising applications in the enzymatic hydrolysis for biochemical production, are established.
Collapse
Affiliation(s)
- Zhonghai Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China; Shandong Provincial Key Laboratory of Microbial Engineering, Department of Bioengineering, Qi Lu University of Technology, Jinan 250353, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
| |
Collapse
|
20
|
Qian Y, Zhong L, Gao J, Sun N, Wang Y, Sun G, Qu Y, Zhong Y. Production of highly efficient cellulase mixtures by genetically exploiting the potentials of Trichoderma reesei endogenous cellulases for hydrolysis of corncob residues. Microb Cell Fact 2017; 16:207. [PMID: 29162107 PMCID: PMC5696804 DOI: 10.1186/s12934-017-0825-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/14/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trichoderma reesei is one of the most important fungi utilized for cellulase production. However, its cellulase system has been proven to be present in suboptimal ratio for deconstruction of lignocellulosic substrates. Although previous enzymatic optimization studies have acquired different types of in vitro synthetic mixtures for efficient lignocellulose hydrolysis, production of in vivo optimized cellulase mixtures by industrial strains remains one of the obstacles to reduce enzyme cost in the biofuels production from lignocellulosic biomass. RESULTS In this study, we used a systematic genetic strategy based on the pyrG marker to overexpress the major cellulase components in a hypercellulolytic T. reesei strain and produce the highly efficient cellulase mixture for saccharification of corncob residues. We found that overexpression of CBH2 exhibited a 32-fold increase in the transcription level and a comparable protein level to CBH1, the most abundant secreted protein in T. reesei, but did not contribute much to the cellulolytic ability. However, when EG2 was overexpressed with a 46-fold increase in the transcription level and a comparable protein level to CBH2, the engineered strain QPE36 showed a 1.5-fold enhancement in the total cellulase activity (up to 5.8 U/mL FPA) and a significant promotion of saccharification efficiency towards differently pretreated corncob residues. To assist the following genetic manipulations, the marker pyrG was successfully excised by homologous recombination based on resistance to 5-FOA. Furthermore, BGL1 was overexpressed in the EG2 overexpression strain QE51 (pyrG-excised) and a 11.6-fold increase in BGL activity was obtained. The EG2-BGL1 double overexpression strain QEB4 displayed a remarkable enhancement of cellulolytic ability on pretreated corncob residues. Especially, a nearly complete cellulose conversion (94.2%) was found for the delignified corncob residues after 48 h enzymatic saccharification. CONCLUSIONS These results demonstrate that genetically exploiting the potentials of T. reesei endogenous cellulases to produce highly efficient cellulase mixtures is a powerful strategy to promote the saccharification efficiency, which will eventually facilitate cost reduction for lignocellulose-based biofuels.
Collapse
Affiliation(s)
- Yuanchao Qian
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Lixia Zhong
- Shandong Institute for Food and Drug Control, Jinan, 250101, People's Republic of China
| | - Jia Gao
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Ningning Sun
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Yifan Wang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Guoyong Sun
- Anaesthesiology Department of the Second Hospital of Shandong University, Jinan, 250100, People's Republic of China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China.
| |
Collapse
|
21
|
Sorokina KN, Samoylova YV, Piligaev AV, Sivakumar U, Parmon VN. New methods for the one-pot processing of polysaccharide components (cellulose and hemicelluloses) of lignocellulose biomass into valuable products. Part 2: Biotechnological approaches to the conversion of polysaccharides and monosaccharides into the valuable industrial chemicals. CATALYSIS IN INDUSTRY 2017. [DOI: 10.1134/s2070050417030126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
22
|
Zhao C, Fang H, Chen S. Single cell oil production by Trichosporon cutaneum from steam-exploded corn stover and its upgradation for production of long-chain α,ω-dicarboxylic acids. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:202. [PMID: 28852423 PMCID: PMC5568358 DOI: 10.1186/s13068-017-0889-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Single cell oil (SCO) production from lignocelluloses by oleaginous microorganisms is still high in production cost, making the subsequent production of biofuels inviable economically in such an era of low oil prices. Therefore, how to upgrade the final products of lignocellulose-based bioprocess to more valuable ones is becoming a more and more important issue. RESULTS Differently sourced cellulases were compared in the enzymatic hydrolysis of the steam-exploded corn stover (SECS) and the cellulase from the mixed culture of Trichoderma reesei and Aspergillus niger was found to have the highest enzymatic hydrolysis yield 86.67 ± 4.06%. Three-stage enzymatic hydrolysis could greatly improve the efficiency of the enzymatic hydrolysis of SECS, achieving a yield of 74.24 ± 2.69% within 30 h. Different bioprocesses from SECS to SCO were compared and the bioprocess C with the three-stage enzymatic hydrolysis was the most efficient, producing 57.15 g dry cell biomass containing 31.80 g SCO from 327.63 g SECS. An efficient and comprehensive process from corn stover to long-chain α,ω-dicarboxylic acids (DCAs) was established by employing self-metathesis, capable of producing 6.02 g long-chain DCAs from 409.54 g corn stover and 6.02 g alkenes as byproducts. CONCLUSIONS On-site cellulase production by the mixed culture of T. reesei and A. niger is proven the most efficient in providing cellulase to the lignocellulose-based bioprocess. Three-stage enzymatic hydrolysis was found to have very good application value in SCO production by Trichosporon cutaneum from SECS. A whole process from corn stover to long-chain DCAs via a combination of biological and chemical approaches was successfully established and it is an enlightening example of the comprehensive utilization of agricultural wastes.
Collapse
Affiliation(s)
- Chen Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100 Shaanxi China
| | - Hao Fang
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100 Shaanxi China
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122 Jiangsu China
| | - Shaolin Chen
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100 Shaanxi China
| |
Collapse
|
23
|
Li Y, Zhang X, Xiong L, Mehmood MA, Zhao X, Bai F. On-site cellulase production and efficient saccharification of corn stover employing cbh2 overexpressing Trichoderma reesei with novel induction system. BIORESOURCE TECHNOLOGY 2017; 238:643-649. [PMID: 28486197 DOI: 10.1016/j.biortech.2017.04.084] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 05/05/2023]
Abstract
Although on-site cellulase production offers cost-effective saccharification of lignocellulosic biomass, low enzyme titer is still a barrier for achieving robustness. In the present study, a strain of T. reesei was developed for enhanced production of cellulase via overexpression of Cellobiohydrolase II. Furthermore, optimum enzyme production was achieved using a novel inducer mixture containing synthesized glucose-sophorose (MGD) and alkali pre-treated corn stover (APCS). Within 60h, a remarkably higher cellulase productivity and activity were achieved in the fed-batch fermentation using the optimized ratio of MGD and APCS in the inducer mixture, compared to those reported using cellulosic biomass as the sole inducer. After the enzyme production, APCS was added directly into the fermentation broth at 20% solid loading, which produced 122.5g/L glucose and 40.21g/L xylose, leading to the highest yield reported so far. The improved enzyme titers during on-site cellulase production would benefit cost-competitive saccharification of lignocellulosic biomass.
Collapse
Affiliation(s)
- Yonghao Li
- State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China.
| | - Xiaoyue Zhang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China.
| | - Liang Xiong
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China.
| | - Muhammad Aamer Mehmood
- State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad 38000, Pakistan.
| | - Xinqing Zhao
- State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Fengwu Bai
- State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China.
| |
Collapse
|
24
|
Xue D, Lin D, Gong C, Peng C, Yao S. Expression of a bifunctional cellulase with exoglucanase and endoglucanase activities to enhance the hydrolysis ability of cellulase from a marine Aspergillus niger. Process Biochem 2017. [DOI: 10.1016/j.procbio.2016.09.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
25
|
Xue DS, Liang LY, Zheng G, Lin DQ, Zhang QL, Yao SJ. Expression of Piromyces rhizinflata cellulase in marine Aspergillus niger to enhance halostable cellulase activity by adjusting enzyme-composition. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2016.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
26
|
Expression of Talaromyces thermophilus lipase gene in Trichoderma reesei by homologous recombination at the cbh1 locus. J Ind Microbiol Biotechnol 2016; 44:377-385. [PMID: 28039549 DOI: 10.1007/s10295-016-1897-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 12/22/2016] [Indexed: 10/20/2022]
Abstract
CBH1 (cellobiohydrolase) comprises the majority of secreted proteins by Trichoderma reesei. For expression of Talaromyces thermophilus lipase gene in T. reesei, a self-designed CBH1 promoter was applied to drive the lipase gene expression cassette which was bracketed by flanking sequences of cbh1 gene for homologous recombination. Protoplast and Agrobacterium-mediated plasmid transformations were performed and compared, resultantly, transformation mediated by Agrobacterium was overall proved to be more efficient. Stable integration of lipase gene into chromosomal DNA of T. reesei transformants was verified by PCR. After shaking flask fermentation, lipase activity of transformant reached 375 IU mL-1, whereas no cellobiohydrolase activity was detected. SDS-PAGE analysis further showed an obvious protein band about 39 kDa and no CBH1 band in fermentation broth, implying lipase gene was successfully extracellularly expressed in T. reesei via homologous recombination at cbh1 locus. This study herein would benefit genetic engineering of filamentous fungi and industrial application of thermo-alkaline lipase like in paper making and detergents addition.
Collapse
|
27
|
Zeng R, Hu Q, Yin XY, Huang H, Yan JB, Gong ZW, Yang ZH. Cloning a novel endo-1,4-β-D-glucanase gene from Trichoderma virens and heterologous expression in E. coli. AMB Express 2016; 6:108. [PMID: 27830495 PMCID: PMC5103005 DOI: 10.1186/s13568-016-0282-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 10/31/2016] [Indexed: 12/16/2022] Open
Abstract
Endo-1,4-β-d-glucanase (EG), as a key constituent of cellulase taking the responsibility of cutting β-1,4 glycosidic bonds, plays the essential role in the process of degrading cellulose by cellulase. Cloning and expressing the EG gene is important to the cellulase research and application. In this work, a novel EG gene was cloned from Trichoderma virens ZY-01, which was a cellulase secreting microbe isolated by our laboratory. The DNA sequence showed that the length of the cloned EG is 1069 bp, which had 95.2% similarity to the EG IV from T. viride AS 3.3711. Further, the expression vector pET-32a-EG was constructed and was successfully heterologously expressed in Escherichia coli. The expression product was purified with Ni2+ affinity chromatography and its enzymatic properties were investigated. The SDS-PAGE showed the target protein is 39 kDa, which is consistent with the translated result from the DNA sequence. The kinetic parameter for the expression product was Km = 13.71 mg/mL and Vmax=0.51 μmol/min·mL. The optimal reaction pH and temperature was pH = 7.0 and T = 40 °C, which is similar to the native EG produced by Trichoderma virens ZY-01. It provides the foundation for the endo-1,4-β-d-glucanase further evolution and application.
Collapse
|
28
|
Li Y, Liu C, Bai F, Zhao X. Overproduction of cellulase by Trichoderma reesei RUT C30 through batch-feeding of synthesized low-cost sugar mixture. BIORESOURCE TECHNOLOGY 2016; 216:503-10. [PMID: 27268435 DOI: 10.1016/j.biortech.2016.05.108] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 05/25/2016] [Accepted: 05/26/2016] [Indexed: 05/05/2023]
Abstract
Cellulase is a prerequisite for the bioconversion of lignocellulosic biomass, but its high cost presents the biggest challenge. In this article, low-cost mixture was produced from glucose through the transglycosylation reaction catalyzed by β-glucosidase for cellulase overproduction by Trichodema reesei RUT C30. As a result, cellulase titer of 90.3FPU/mL, which was more than 10 folds of that achieved with lactose as inducer, was achieved at 144h. Meanwhile, cellulase productivity was drastically increased to 627.1FPU/L/h, at least 3-5 folds higher than previously reported by the fungal species. The crude enzyme was further tested by hydrolyzing NaOH-pretreated corn stover with 15% solid loading, and 96.6g/L glucose was released with 92.6% sugar yield at 96h and 44.8g/L ethanol was obtained.
Collapse
Affiliation(s)
- Yonghao Li
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China.
| | - Chenguang Liu
- State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Fengwu Bai
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China; State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Xinqing Zhao
- State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| |
Collapse
|
29
|
Zhao X, Xiong L, Zhang M, Bai F. Towards efficient bioethanol production from agricultural and forestry residues: Exploration of unique natural microorganisms in combination with advanced strain engineering. BIORESOURCE TECHNOLOGY 2016; 215:84-91. [PMID: 27067672 DOI: 10.1016/j.biortech.2016.03.158] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 05/14/2023]
Abstract
Production of fuel ethanol from lignocellulosic feedstocks such as agricultural and forestry residues is receiving increasing attention due to the unsustainable supply of fossil fuels. Three key challenges include high cellulase production cost, toxicity of the cellulosic hydrolysate to microbial strains, and poor ability of fermenting microorganisms to utilize certain fermentable sugars in the hydrolysate. In this article, studies on searching of natural microbial strains for production of unique cellulase for biorefinery of agricultural and forestry wastes, as well as development of strains for improved cellulase production were reviewed. In addition, progress in the construction of yeast strains with improved stress tolerance and the capability to fully utilize xylose and glucose in the cellulosic hydrolysate was also summarized. With the superior microbial strains for high titer cellulase production and efficient utilization of all fermentable sugars in the hydrolysate, economic biofuels production from agricultural residues and forestry wastes can be realized.
Collapse
Affiliation(s)
- Xinqing Zhao
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Liang Xiong
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Mingming Zhang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Fengwu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| |
Collapse
|
30
|
Fang H, Zhao C, Chen S. Single cell oil production by Mortierella isabellina from steam exploded corn stover degraded by three-stage enzymatic hydrolysis in the context of on-site enzyme production. BIORESOURCE TECHNOLOGY 2016; 216:988-95. [PMID: 27343451 DOI: 10.1016/j.biortech.2016.06.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 05/23/2023]
Abstract
Single cell oil (SCO), promising as alternative oil source, was produced from steam exploded corn stover (SECS) by Mortierella isabellina. Different bioprocesses from SECS to SCO were compared and the bioprocess C using the three-stage enzymatic hydrolysis was found to be the most efficient one. The bioprocess C used the lowest enzyme input 20FPIU cellulase/g glucan and the shortest time 222h, but produced 44.94g dry cell biomass and 25.77g lipid from 327.63g dry SECS. It had the highest lipid content 57.34%, and its productivities and yields were much higher than those of the bioprocess B and comparable to the bioprocess A, indicating that the three-stage enzymatic hydrolysis could greatly improve the efficiency of the bioprocess from high solid loading SECS to SCO by Mortierella isabellina. This work testified the application value of three-stage enzymatic hydrolysis in lignocellulose-based bioprocesses.
Collapse
Affiliation(s)
- Hao Fang
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi 712100, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.
| | - Chen Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi 712100, China
| | - Shaolin Chen
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi 712100, China
| |
Collapse
|
31
|
Zhang X, Li X, Xia L. Heterologous Expression of an Alkali and Thermotolerant Lipase from Talaromyces thermophilus in Trichoderma reesei. Appl Biochem Biotechnol 2015; 176:1722-35. [DOI: 10.1007/s12010-015-1673-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/19/2015] [Indexed: 01/28/2023]
|
32
|
Heterologous protein expression in Hypocrea jecorina: a historical perspective and new developments. Biotechnol Adv 2014; 33:142-154. [PMID: 25479282 DOI: 10.1016/j.biotechadv.2014.11.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/18/2014] [Accepted: 11/23/2014] [Indexed: 10/24/2022]
Abstract
Hypocrea jecorina, the sexual teleomorph of Trichoderma reesei, has long been favored as an industrial cellulase producer, first utilizing its native cellulase system and later augmented by the introduction of heterologous enzymatic activities or improved variants of native enzymes. Expression of heterologous proteins in H. jecorina was once considered difficult when the target was an improved variant of a native cellulase. Developments over the past nearly 30 years have produced strains, vectors, and selection mechanisms that have continued to simplify and streamline heterologous protein expression in this fungus. More recent developments in fungal molecular biology have pointed the way toward a fundamental transformation in the ease and efficiency of heterologous protein expression in this important industrial host. Here, 1) we provide a historical perspective on advances in H. jecorina molecular biology, 2) outline host strain engineering, transformation, selection, and expression strategies, 3) detail potential pitfalls when working with this organism, and 4) provide consolidated examples of successful cellulase expression outcomes from our laboratory.
Collapse
|
33
|
Li Q, Ng WT, Wu JC. Isolation, characterization and application of a cellulose-degrading strain Neurospora crassa S1 from oil palm empty fruit bunch. Microb Cell Fact 2014; 13:157. [PMID: 25384340 PMCID: PMC4232651 DOI: 10.1186/s12934-014-0157-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 10/22/2014] [Indexed: 01/05/2023] Open
Abstract
Background Oil palm empty fruit bunch (EFB) is a lignocellulosic waste produced in palm oil industry. EFB mainly consists of cellulose, hemicellulose (mainly xylan) and lignin and has a great potential to be reused. Converting EFB to fermentable sugars and value-added chemicals is a much better choice than treating EFB as waste. Results A cellulase-producing strain growing on oil palm empty fruit bunch (EFB) was isolated and identified as Neurospora crassa S1, which is able to produce cellulases using EFB as the sole carbon source. The strain started to secret cellulases into the medium after 24 h of cultivation at 30°C and reached its maximal cellulase activity at 240 h. Mass spectroscopy (MS) analysis showed that more than 50 proteins were secreted into the medium when EFB was used as the sole carbon source. Among them, 7 proteins were identified as putative enzymes associated with cellulose degradation. The whole cell culture of Neurospora crassa S1 was used to hydrolyze acid-treated EFB, giving a total sugar yield of 83.2%, which is comparable with that (82.0%) using a well-known cellulase producer Trichoderma reesei RUT-C30 (ATCC56765). Conclusion Neurospora crassa S1 is a commercially promising native cellulase producer for EFB hydrolysis especially when the sugars obtained are to be fermented to products that require use of non-genetically engineered strains.
Collapse
Affiliation(s)
- Qingxin Li
- Institute of Chemical & Engineering Sciences, Agency for Science, Technology and Research, 1 Pesek Road, Jurong Island, Singapore, 627833, Singapore.
| | - Wei Ting Ng
- Institute of Chemical & Engineering Sciences, Agency for Science, Technology and Research, 1 Pesek Road, Jurong Island, Singapore, 627833, Singapore.
| | - Jin Chuan Wu
- Institute of Chemical & Engineering Sciences, Agency for Science, Technology and Research, 1 Pesek Road, Jurong Island, Singapore, 627833, Singapore.
| |
Collapse
|
34
|
Akinosho H, Yee K, Close D, Ragauskas A. The emergence of Clostridium thermocellum as a high utility candidate for consolidated bioprocessing applications. Front Chem 2014; 2:66. [PMID: 25207268 PMCID: PMC4143619 DOI: 10.3389/fchem.2014.00066] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/28/2014] [Indexed: 01/25/2023] Open
Abstract
First isolated in 1926, Clostridium thermocellum has recently received increased attention as a high utility candidate for use in consolidated bioprocessing (CBP) applications. These applications, which seek to process lignocellulosic biomass directly into useful products such as ethanol, are gaining traction as economically feasible routes toward the production of fuel and other high value chemical compounds as the shortcomings of fossil fuels become evident. This review evaluates C. thermocellum's role in this transitory process by highlighting recent discoveries relating to its genomic, transcriptomic, proteomic, and metabolomic responses to varying biomass sources, with a special emphasis placed on providing an overview of its unique, multivariate enzyme cellulosome complex and the role that this structure performs during biomass degradation. Both naturally evolved and genetically engineered strains are examined in light of their unique attributes and responses to various biomass treatment conditions, and the genetic tools that have been employed for their creation are presented. Several future routes for potential industrial usage are presented, and it is concluded that, although there have been many advances to significantly improve C. thermocellum's amenability to industrial use, several hurdles still remain to be overcome as this unique organism enjoys increased attention within the scientific community.
Collapse
Affiliation(s)
- Hannah Akinosho
- School of Chemistry and Biochemistry, Institute of Paper Science and Technology, Georgia Institute of Technology Atlanta, GA, USA ; Oak Ridge National Laboratory, BioEnergy Science Center Oak Ridge, TN, USA
| | - Kelsey Yee
- Oak Ridge National Laboratory, BioEnergy Science Center Oak Ridge, TN, USA ; Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Dan Close
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
| | - Arthur Ragauskas
- Oak Ridge National Laboratory, BioEnergy Science Center Oak Ridge, TN, USA ; Department of Chemical and Biomolecular Engineering and Department of Forestry, Wildlife, and Fisheries, University of Tennessee Knoxville, TN, USA
| |
Collapse
|