title: Enhanced solvent production by metabolic engineering of a twin-clostridial consortium.
abstract: The efficient fermentative production of solvents (acetone, n-butanol, and ethanol) from a lignocellulosic feedstock using a single process microorganism has yet to be demonstrated. Herein, we developed a consolidated bioprocessing (CBP) based on a twin-clostridial consortium composed of Clostridium cellulovorans and Clostridium beijerinckii capable of producing cellulosic butanol from alkali-extracted, deshelled corn cobs (AECC). To accomplish this a genetic system was developed for C. cellulovorans and used to knock out the genes encoding acetate kinase (Clocel_1892) and lactate dehydrogenase (Clocel_1533), and to overexpress the gene encoding butyrate kinase (Clocel_3674), thereby pulling carbon flux towards butyrate production. In parallel, to enhance ethanol production, the expression of a putative hydrogenase gene (Clocel_2243) was down-regulated using CRISPR interference (CRISPRi). Simultaneously, genes involved in organic acids reassimilation (ctfAB, cbei_3833/3834) and pentose utilization (xylR, cbei_2385 and xylT, cbei_0109) were engineered in C. beijerinckii to enhance solvent production. The engineered twin-clostridia consortium was shown to decompose 83.2g/L of AECC and produce 22.1g/L of solvents (4.25g/L acetone, 11.5g/L butanol and 6.37g/L ethanol). This titer of acetone-butanol-ethanol (ABE) approximates to that achieved from a starchy feedstock. The developed twin-clostridial consortium serves as a promising platform for ABE fermentation from lignocellulose by CBP.
authors: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors: Zhiqiang
authors: Z
authors: Wen
authors: Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), University of Nottingham, Nottingham, UK.
authors: Nigel P
authors: NP
authors: Minton
authors: Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), University of Nottingham, Nottingham, UK.
authors: Ying
authors: Y
authors: Zhang
authors: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; Graduate University of the Chinese Academy of Sciences, Beijing, China.
authors: Qi
authors: Q
authors: Li
authors: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; Graduate University of the Chinese Academy of Sciences, Beijing, China.
authors: Jinle
authors: J
authors: Liu
authors: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; Shanghai Research and Development Center of Industrial Biotechnology, Shanghai, China.
authors: Yu
authors: Y
authors: Jiang
authors: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; Shanghai Research and Development Center of Industrial Biotechnology, Shanghai, China; Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing, China. Electronic address: syang@sibs.ac.cn.
authors: Sheng
authors: S
authors: Yang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D053898:Biosynthetic Pathways / Q000502:physiology; D000440:Butanols / Q000302:isolation & purification / Q000378:metabolism*; D003013:Clostridium / Q000166:cytology / Q000502:physiology*; D018920:Coculture Techniques / Q000379:methods; D005285:Fermentation / Q000502:physiology; D024861:Genetic Enhancement / Q000379:methods*; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways / Q000502:physiology; D059013:Microbial Consortia / Q000235:genetics*; D012997:Solvents / Q000302:isolation & purification / Q000378:metabolism; D003313:Zea mays / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D000440:Butanols; D012997:Solvents
keywords: Acetone-butanol-ethanol fermentation; Consolidated bioprocessing; Genetic system; Modular metabolic engineering; Twin-clostridia consortium