Title: Proteomic Analyses of Ethanol Tolerance in Lactobacillus buchneri NRRL B-30929 Author
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 20, 2014
Publication Date: N/A
Technical Abstract: The Lactobacillus buchneri NRRL B-30929 strain, isolated from a fuel ethanol production facility, exhibits high tolerance to environmental ethanol concentrations. In this study, the ethanol tolerance trait was elucidated at the molecular level by using proteomics comparison and analyses. Cellular proteins expressed by B-30929 growing in media with 6 or 10% ethanol were compared with that of 0% ethanol control. The expression levels of more than 72 proteins were altered upon ethanol treatment. Changes are more evident in cellular proteins in media with 10% ethanol. Bioinformatics analyses identified 24 proteins responsive to ethanol stress. These include protein degradation [U34 dipeptidase (Gene ID: Lbuc_1059), a proline-specific peptidase (Lbuc_1852)]; protein synthesis [translation elongation factor G (Lbuc_1730)]; enzymes involved in redox potential balances [nitroreductase (Lbuc_2051), glyoxylate reductase (Lbuc_0188), and methylglyoxal reductase (Lbuc_0522)]; enzymes involved in carbohydrate metabolism [phosphoglycerate kinase (EC 22.214.171.124, Lbuc_1319) and phosphogluconate dehydrogenase (Lbuc_2157)]; nitrogen, amino acid, and fatty acid metabolism [ ureidoglycolate lyase (EC 126.96.36.199 Lbuc_1994), ornithine carbamoyltransferase (Lbuc_0446), glycine hydroxymethytrasferase (Lbuc_0858), cobyrinic acid acdiamide synthase (Lbuc_2426), branched-chain amino acid aminotransferase Lbuc_0707), and. fumarylacetoacetate hydrolase (Lbuc_0787)]. These changes suggested adaptation of B-30929 to environmental ethanol by shifting from oxidative to reductive metabolisms and resulting degradation of available proteins and fatty acids and synthesis of new enzymes and other molecules dealing with ethanol stress. Membrane protein yajC (Lbuc_0921), general stress related 10 kDa chaperonin (GroESL Lbuc_1359) and a 29 kDa protein of the HK 97 family (Lbuc_1523) were found increased during growth with ethanol in media. These results can be used to guide genetic modifications to increase ethanol tolerance in industrial fermentations.