Improved ethanol tolerance and ethanol production from glycerol in a streptomycin-resistant Klebsiella variicola mutant obtained by ribosome engineering

Bioresour Technol. 2015 Jan:176:156-62. doi: 10.1016/j.biortech.2014.10.153. Epub 2014 Nov 13.

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.

Keywords: Ethanol production; Ethanol tolerance; Glycerol; Klebsiella variicola; Ribosome engineering.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Batch Cell Culture Techniques
  • Biofuels*
  • Culture Media
  • Drug Resistance, Bacterial
  • Ethanol / metabolism*
  • Fermentation
  • Formates / metabolism
  • Glycerol / metabolism*
  • Klebsiella / drug effects
  • Klebsiella / genetics
  • Klebsiella / metabolism*
  • Mutation
  • Protein Engineering
  • Ribosomes / genetics*
  • Streptomycin / pharmacology

Substances

  • Biofuels
  • Culture Media
  • Formates
  • formic acid
  • Ethanol
  • Glycerol
  • Streptomycin