1. Genome tailoring powered production of isobutanol in continuous CO/H blend fermentation using engineered acetogen biocatalyst.
- Author
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Gak, Eugene, Tyurin, Michael, and Kiriukhin, Michael
- Subjects
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ISOBUTANOL , *FERMENTATION , *POLYKETIDES , *NUCLEOTIDE sequence , *CLOSTRIDIUM , *GENE expression in bacteria - 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 CO/H gas blend. Biocatalyst Clostridium sp. MT871RGIB6 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 CO/H blend thus contributing to the reversal of global warming. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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