1
|
Exploiting the Type I-B CRISPR Genome Editing System in Thermoanaerobacterium aotearoense SCUT27 and Engineering the Strain for Enhanced Ethanol Production. Appl Environ Microbiol 2022; 88:e0075122. [PMID: 35862665 PMCID: PMC9361813 DOI: 10.1128/aem.00751-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Thermoanaerobacterium aotearoense strain SCUT27 is a potential industrial biofuel-producing strain because of its broad substrate spectrum, especially the ability to co-use glucose and xylose. The bottleneck hindering the development of strain SCUT27 is the lack of selective markers for polygene manipulation in this thermophilic bacterium. In this study, the endogenous type I-B clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system was developed for multiplex genome editing of strain SCUT27. The protospacer-adjacent motif was identified by in silico analysis and verified with orotidine-5'-phosphate decarboxylase (pyrF) or lactate dehydrogenase (ldh) as the editing target. The type I-B CRISPR/Cas system was functional in strain SCUT27 with 58.3% to 100% editing efficiency. A multiplex genome editing method based on thymidine kinase (tdk) as a negative selection marker was developed, and strain SCUT27/Δtdk/Δldh/ΔargR, in which ldh and the arginine repressor (argR) were knocked out successively, was successfully obtained. Strain SCUT27/Δtdk/Δldh/ΔargR exhibited prominent advantages over wild-type SCUT27 in ethanol production, with significantly improved ability to metabolize xylose. IMPORTANCE Thermophilic microbes have attracted great attention as potential candidates for production of biofuels and chemicals from lignocellulose because of their thermal tolerance and wide substrate spectra. The ability to edit multiple genes using the native type I-B CRISPR/Cas system would speed up engineering of Thermoanaerobacterium aotearoense strain SCUT27 for higher ethanol production from lignocellulosic hydrolysates. Here, we produced a mutant strain, T. aotearoense SCUT27/Δtdk/Δldh/ΔargR, using the native CRISPR/Cas system. The engineered strain showed satisfactory performance with improved ethanol productivity from various lignocellulosic hydrolysates. Our data lay the foundations for development of this thermophilic microbe into an excellent ethanol producer using lignocellulosic hydrolysates. The methods described here may also provide a reference to develop multigene editing methods for other microorganisms.
Collapse
|
2
|
Wu M, Jiang Y, Liu Y, Mou L, Zhang W, Xin F, Jiang M. Microbial application of thermophilic Thermoanaerobacterium species in lignocellulosic biorefinery. Appl Microbiol Biotechnol 2021; 105:5739-5749. [PMID: 34283269 DOI: 10.1007/s00253-021-11450-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 12/13/2022]
Abstract
Recently, thermophilic Thermoanaerobacterium species have attracted increasing attentions in consolidated bioprocessing (CBP), which can directly utilize lignocellulosic materials for biofuels production. Compared to the mesophilic process, thermophilic process shows greater prospects in CBP due to its relatively highly efficiency of lignocellulose degradation. In addition, thermophilic conditions can avoid microbial contamination, reduce the cooling costs, and further facilitate the downstream product recovery. However, only few reviews specifically focused on the microbial applications of thermophilic Thermoanaerobacterium species in lignocellulosic biorefinery. Accordingly, this review will comprehensively summarize the recent advances of Thermoanaerobacterium species in lignocellulosic biorefinery, including their secreted xylanases and bioenergy production. Furthermore, the co-culture can significantly reduce the metabolic burden and achieve the more complex work, which will be discussed as the further perspectives. KEY POINTS: • Thermoanaerobacterium species, promising chassis for lignocellulosic biorefinery. • Potential capability of hemicellulose degradation for Thermoanaerobacterium species. • Efficient bioenergy production by Thermoanaerobacterium species through metabolic engineering.
Collapse
Affiliation(s)
- Mengdi Wu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211800, People's Republic of China
| | - Yujia Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211800, People's Republic of China
| | - Yansong Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211800, People's Republic of China
| | - Lu Mou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211800, People's Republic of China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211800, People's Republic of China.
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, People's Republic of China.
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211800, People's Republic of China.
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, People's Republic of China.
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University, Puzhu South Road 30#, Nanjing, 211800, People's Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, People's Republic of China
| |
Collapse
|
3
|
Qu C, Zhang Y, Dai K, Fu H, Wang J. Metabolic engineering of Thermoanaerobacterium aotearoense SCUT27 for glucose and cellobiose co-utilization by identification and overexpression of the endogenous cellobiose operon. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2020.107922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
4
|
Zhu M, Zhang L, Yang F, Cha Y, Li S, Zhuo M, Huang S, Li J. A Recombinant β-Mannanase from Thermoanaerobacterium aotearoense SCUT27: Biochemical Characterization and Its Thermostability Improvement. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:818-825. [PMID: 31845578 DOI: 10.1021/acs.jafc.9b06246] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
β-Mannanase was expressed in Thermoanaerobacterium aotearoense SCUT27 induced by locust bean gum (LBG). The open reading frame encoding a GH26 β-mannanase was identified and encoded a preprotein of 515 amino acids with a putative signal peptide. The enzyme without a signal sequence (Man25) was overexpressed in Escherichia coli with a specific activity of 1286.2 U/mg. Moreover, a facile method for β-mannanase activity screening was established based on agar plates. The optimum temperature for the purified Man25 using LBG as a substrate was 55 °C. The catalytic activity and thermostability of Man25 displayed a strong dependence on calcium ions. Through saturation mutagenesis at the putative Ca2+ binding sites in Man25, the best mutant ManM3-3 (D143A) presented improvements in thermostability with 3.6-fold extended half-life at 55 °C compared with that of the wild-type. The results suggest that mutagenesis at metal binding sites could be an efficient approach to increase enzyme thermostability.
Collapse
Affiliation(s)
- Muzi Zhu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology , Guangdong Academy of Sciences , Guangzhou 510070 , China
| | | | - Fang Yang
- Integrative Microbiology Research Centre , South China Agricultural University , Guangzhou 510642 , China
| | | | | | | | | | - Jianjun Li
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology , Guangdong Academy of Sciences , Guangzhou 510070 , China
| |
Collapse
|