title: Improved ethanol tolerance and ethanol production from glycerol in a streptomycin-resistant Klebsiella variicola mutant obtained by ribosome engineering.
abstract: To improve the ethanol tolerance of the Klebsiella variicola strain TB-83, we obtained the streptomycin-resistant, ethanol-tolerant mutant strain TB-83D by a ribosome engineering approach. Strain TB-83D was able to grow in the presence of 7% (v/v) ethanol and it showed higher ethanol production than strain TB-83. Examination of various culture conditions revealed that yeast extract was essential for ethanol production and bacterial growth. In addition, ethanol production was elevated to 32g/L by the addition of yeast extract; however, ethanol production was inhibited by formate accumulation. With regard to cost reduction, the use of corn steep liquor (CSL) markedly decreased the formate concentration, and 34g/L ethanol was produced by combining yeast extract with CSL. Our study is the first to improve ethanol tolerance and productivity by a ribosome engineering approach, and we found that strain TB-83D is effective for ethanol production from glycerol.
authors.affiliation: Faculty of Life and Environmental Sciences (Bioindustrial Sciences), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Faculty of Life and Environmental Sciences (Bioindustrial Sciences), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Seta
authors.affiliation: Faculty of Life and Environmental Sciences (Bioindustrial Sciences), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Nishikawa
authors.affiliation: Faculty of Life and Environmental Sciences (Bioindustrial Sciences), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Hara
authors.affiliation: Tsukuba Institute of Environmental Microbiology, 8-1 Sakuragaoka, Tsukuba, Ibaraki 300-1271, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Shigeno
authors.affiliation: Faculty of Life and Environmental Sciences (Bioindustrial Sciences), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan. Electronic address: nakajima.toshiaki.ga@u.tsukuba.ac.jp.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nakajima-Kambe
mesh_terms: D061249:Batch Cell Culture Techniques; D056804:Biofuels; D003470:Culture Media; D024881:Drug Resistance, Bacterial; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005561:Formates / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism*; D007709:Klebsiella / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D015202:Protein Engineering; D012270:Ribosomes / Q000235:genetics*; D013307:Streptomycin / Q000494:pharmacology
chemical_list: D056804:Biofuels; D003470:Culture Media; D005561:Formates; C030544:formic acid; D000431:Ethanol; D005990:Glycerol; D013307:Streptomycin
keywords: Ethanol production; Ethanol tolerance; Glycerol; Klebsiella variicola; Ribosome engineering