Metabolic engineering of Thermoanaerobacterium aotearoense strain SCUT27 for biofuels production from sucrose and molasses

Biotechnology for Biofuels and Bioproducts

Research

Chunyun Qu¹  Jun Feng²  Kaiqun Dai²  Yang Lan²  Jufang Wang³  Hongxin Fu³ 

[1] College of Light Industry and Food Science, Guangdong Provincial Key Laboratory of Science and Technology of Lingnan Special Food Science and Technology, Zhongkai University of Agriculture and Engineering, 510225, Guangzhou, China;School of Biology and Biological Engineering, South China University of Technology, 510006, Guangzhou, China;School of Biology and Biological Engineering, South China University of Technology, 510006, Guangzhou, China;Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, 510006, Guangzhou, China;

关键词: Thermoanaerobacterium;    Sucrose;    Metabolic engineering;    Cane molasses;    Biofuels;   

DOI  :  10.1186/s13068-023-02402-3

 received in 2023-05-28, accepted in 2023-09-21,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundSucrose-rich sugarcane trash surpasses 28 million tons globally per year. Effective biorefinery systems could convert these biomasses to bioproducts, such as bioethanol from sugarcane sucrose in Brazil. Thermophilic microbes for biofuels have attracted great attention due to their higher fermentation temperature and wide substrate spectrum. However, few thermophiles using sucrose or molasses for biofuels production was reported. Thermoanaerobacterium aotearoense SCUT27 has been considered as an efficient ethanol producer, but it cannot directly utilize sucrose. In this study, various sucrose metabolic pathways were introduced and analyzed in Thermoanaerobaterium.ResultsThe sucrose-6-phosphate hydrolase (scrB), which was from a screened strain Thermoanaerobacterium thermosaccharolyticum G3-1 was overexpressed in T. aotearoense SCUT27 and endowed this strain with the ability to utilize sucrose. In addition, overexpression of the sucrose-specific PTS system (scrA) from Clostridium acetobutylicum accelerated the sucrose transport. To strengthen the alcohols production and substrates metabolism, the redox-sensing transcriptional repressor (rex) in T. aotearoense was further knocked out. Moreover, with the gene arginine repressor (argR) deleted, the ethanologenic mutant P8S10 showed great inhibitors-tolerance and finally accumulated ~ 34 g/L ethanol (a yield of 0.39 g/g sugars) from pretreated cane molasses in 5 L tank by fed-batch fermentation. When introducing butanol synthetic pathway, 3.22 g/L butanol was produced by P8SB4 with a yield of 0.44 g alcohols/g sugars at 50℃. This study demonstrated the potential application of T. aotearoense SCUT27 for ethanol and butanol production from low cost cane molasses.ConclusionsOur work provided strategies for sucrose utilization in thermophiles and improved biofuels production as well as stress tolerances of T. aotearoense SCUT27, demonstrating the potential application of the strain for cost-effective biofuels production from sucrose-based feedstocks.

【 授权许可】

CC BY   
© BioMed Central Ltd., part of Springer Nature 2023

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