title: Genome tailoring powered production of isobutanol in continuous CO2/H2 blend fermentation using engineered acetogen biocatalyst.
abstract: The cell energy fraction that powered maintenance and expression of genes encoding pro-phage elements, pta-ack cluster, early sporulation, sugar ABC transporter periplasmic proteins, 6-phosphofructokinase, pyruvate kinase, and fructose-1,6-disphosphatase in acetogen Clostridium sp. MT871 was re-directed to power synthetic operon encoding isobutanol biosynthesis at the expense of these genes achieved via their elimination. Genome tailoring decreased cell duplication time by 7.0 ± 0.1 min (p < 0.05) compared to the parental strain, with intact genome and cell duplication time of 68 ± 1 min (p < 0.05). Clostridium sp. MT871 with tailored genome was UVC-mutated to withstand 6.1 % isobutanol in fermentation broth to prevent product inhibition in an engineered commercial biocatalyst producing 5 % (674.5 mM) isobutanol during two-step continuous fermentation of CO2/H2 gas blend. Biocatalyst Clostridium sp. MT871RG- 11IBR6 was engineered to express six copies of synthetic operon comprising optimized synthetic format dehydrogenase, pyruvate formate lyase, acetolactate synthase, acetohydroxyacid reductoisomerase, 2,3-dihydroxy-isovalerate dehydratase, branched-chain alpha-ketoacid decarboxylase gene, aldehyde dehydrogenase, and alcohol dehydrogenase, regaining cell duplication time of 68 ± 1 min (p < 0.05) for the parental strain. This is the first report on isobutanol production by an engineered acetogen biocatalyst suitable for commercial manufacturing of this chemical/fuel using continuous fermentation of CO2/H2 blend thus contributing to the reversal of global warming.
authors.forename: Eugene
authors.initials: E
authors.lastname: Gak
authors.forename: Michael
authors.initials: M
authors.lastname: Tyurin
authors.forename: Michael
authors.initials: M
authors.lastname: Kiriukhin
mesh_terms: D000085:Acetates / Q000378:metabolism; D055162:Biocatalysis; D000440:Butanols / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D060846:Cell Engineering; D003013:Clostridium / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D005285:Fermentation; D005740:Gases; D017353:Gene Deletion; D016680:Genome, Bacterial; D006859:Hydrogen / Q000378:metabolism; D016296:Mutagenesis
chemical_list: D000085:Acetates; D000440:Butanols; D005227:Fatty Acids; D005740:Gases; D002245:Carbon Dioxide; C040507:isobutyl alcohol; D006859:Hydrogen