Submitted to: Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2014
Publication Date: 9/22/2014
Publication URL: http://handle.nal.usda.gov/10113/5642487
Citation: Liu, S. 2014. Proteomic analyses of ethanol tolerance in Lactobacillus buchneri NRRL B-30929. Proteomics. 14(21-22):2540-2544.
Interpretive Summary: The Lactobacillus buchneri NRRL B-30929 strain isolated from a fuel ethanol plant uses a mixture of five-carbon and six-carbon sugars commonly found in lignocellulosic biomass. This strain also exhibits high tolerance to environmental ethanol concentrations. In this paper, 20 specific proteins produced by B-30929 in response to high environmental ethanol contents were identified by proteomics analyses. These results can be used to guide genetic modifications to increase ethanol tolerance in industrial biocatalysts.
Technical Abstract: The Lactobacillus buchneri NRRL B-30929 strain, isolated from a fuel ethanol production facility, exhibits high tolerance to environmental ethanol concentrations. This study aimed to identify proteins produced by B-30929 in response to environmental ethanol. Cellular proteins expressed by B-30929 growing in media with 10% vs. 0% ethanol were compared by 2D gel electrophoresis, followed by in gel digestion and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analyses. Twenty ethanol responsive proteins were indentified. These include a proline-specific peptidase (Lbuc_1852); a membrane protein (Lbuc_0921), two general stress related 10 kDa chaperonin (GroESL Lbuc_1359) and a 29 kDa member of the HK 97 family (Lbuc_1523); metabolic enzymes involving redox potential balances (Lbuc_2051) and (Lbuc_0522)] and carbohydrate fermentation [phosphoglycerate kinase (EC 220.127.116.11, Lbuc_1319) and phosphogluconate dehydrogenase (Lbuc_2157)]; nitrogen, amino acid and fatty acid metabolism [ureidoglycolate lyase (EC 18.104.22.168 Lbuc_1994), ornithine carbamoyltransferase (Lbuc_0446), glycine hydroxymethytrasferase (Lbuc_0858), branched-chain amino acid aminotransferase Lbuc_0707), and fumarylacetoacetate hydrolase (Lbuc_0787)]. These changes suggested B-30929 cells respond to ethanol by degradation of available proteins and fatty acids and synthesis of new enzymes and molecular chaperons, plus a shift from oxidative to reductive metabolisms. These changes resulted in an ethanol-tolerant phenotype. These results can be used to guide genetic modifications to increase ethanol tolerance in industrial biocatalysts.