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Indexed by:期刊论文

Date of Publication:2018-09-01

Journal:APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

Included Journals:PubMed、SCIE

Volume:102

Issue:18

Page Number:8107-8119

ISSN No.:0175-7598

Key Words:Clostridium acetobutylicum; Vitamin B1 biosynthesis; Carbohydrate metabolism; Acetone-butanol-ethanol fermentation

Abstract:Vitamin B1 (VB1) is an essential coenzyme for carbohydrate metabolism and involved in energy generation in most organisms. In this study, we found that insufficient biosynthesis of VB1 in Clostridium acetobutylicum ATCC 824 is a major limiting factor for efficient acetone-butanol-ethanol (ABE) fermentation. In order to improve the fermentation performance of C. acetobutylicum ATCC 824, the VB1 biosynthesis pathway was strengthened by overexpressing the thiC, thiG, and thiE genes. The engineered strain 824(thiCGE) showed enhanced VB1 and energy synthesis, resulting in better growth, faster sugar consumption, higher solvents production, and lower acids formation than the wild-type strain in both VB1 free and normal P2 medium (1 mg/L). Compared with the wild-type strain, 824(thiCGE) produced 13.0 +/- 0.1% or 12.7 +/- 1.2% more butanol in VB1 free P2 medium when glucose or xylose was used as the substrate, respectively. When mixed sugar (glucose:xylose = 2:1) was used as the substrate in VB1 free P2 medium, the xylose consumption rate and butanol titer of 824(thiCGE) were 45.8 +/- 1.9% and 20.4 +/- 0.3% higher than those of the wild-type strain. All these results demonstrated that this metabolic engineering strategy could provide a new and effective way to improve the cellular performance of solventogenic clostridia. In addition, it may have some potential application value in ABE fermentation using simple medium and/or lignocellulosic biomass.