O-030. Proteomic Approach for Molecular Mechanisms under Ethanol Stress in Lactobacillus buchneri

S. Liu;

Lactic acid bacteria have potential to serve as microbial catalysts for production of fuels and chemicals from lignocellulosic biomass. Lactobacillus buchneri NRRL B-30929 is a novel strain that belongs to the hetero-fermentative group of lactic acid bacteria. It was isolated from a fuel ethanol production facility and shown to produce equal molar amounts of lactic acid and ethanol from glucose under anaerobic conditions. Most notably, the microbe exhibited exhibits high tolerance to environmental ethanol concentrations. When medium was supplied with up to 6% ethanol, no visible delay of growth was observed. Approximately 30% to 70% decrease of total cell number was detected when concentrations were increased to 10% to 14% ethanol. Total cellular proteins from duplicate cultures of 0%, 6%, and 10% ethanol were subjected to 2D-gel electrophoresis. Comparisons of between 0% ethanol and 6% or 10% ethanol indicated changes to the protein profiles in both 6% and 10% ethanol treated cells. Both increases and decreases in density of several proteins were visible, with the changes more evident in cells with 10% ethanol. The identification of ethanol stress related proteins will help us to understand the molecular mechanisms governing tolerance to high ethanol concentrations. Combined with genomic analyses, these proteomic data will lead to cloning specific ethanol tolerance related genes which may be used for improving biocatalysts for efficient conversion of biomass to biofuel.

178/O. Emerging Technology and Instrumentation

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