title: Improving the performance of solventogenic clostridia by reinforcing the biotin synthetic pathway.
abstract: An efficient production process is important for industrial microorganisms. The cellular efficiency of solventogenic clostridia, a group of anaerobes capable of producing a wealth of bulk chemicals and biofuels, must be improved for competitive commercialization. Here, using Clostridium acetobutylicum, a species of solventogenic clostridia, we revealed that the insufficient biosynthesis of biotin, a pivotal coenzyme for many important biological processes, is a major limiting bottleneck in this anaerobe's performance. To address this problem, we strengthened the biotin synthesis of C. acetobutylicum by overexpressing four relevant genes involved in biotin transport and biosynthesis. This strategy led to faster growth and improved the titer and productivity of acetone, butanol and ethanol (ABE solvents) of C. acetobutylicum in both biotin-containing and biotin-free media. Expressionally modulating these four genes by modifying the ribosome binding site further promoted cellular performance, achieving ABE solvent titer and productivity as high as 21.9g/L and 0.30g/L/h, respectively, in biotin-free medium; these values exceeded those of the wild-type strain by over 30%. More importantly, biotin synthesis reinforcement also conferred improved ability of C. acetobutylicum to use hexose and pentose sugars, further demonstrating the potential of this metabolic-engineering strategy in solventogenic clostridia.
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Nannan
authors.initials: N
authors.lastname: Lang
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Gaohua
authors.initials: G
authors.lastname: Yang
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Meilong Road, Shanghai 200237, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Meilong Road, Shanghai 200237, China. Electronic address: whjiang@sibs.ac.cn.
authors.forename: Weihong
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China. Electronic address: ygu02@sibs.ac.cn.
authors.forename: Yang
authors.initials: Y
authors.lastname: Gu
mesh_terms: D000096:Acetone / Q000378:metabolism*; D001710:Biotin / Q000096:biosynthesis / Q000235:genetics; D000440:Butanols / Q000378:metabolism*; D046969:Clostridium acetobutylicum / Q000235:genetics / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D060847:Metabolic Engineering
chemical_list: D000440:Butanols; D000096:Acetone; D000431:Ethanol; D001710:Biotin
keywords: Biotin synthesis reinforcement; Engineering robust clostridia; Solvent titer and productivity