Location: Renewable Product Technology ResearchTitle: Identification of butanol tolerant genes in Lactobacillus mucosae
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/12/2016
Publication Date: 6/20/2016
Citation: Liu, S., Qureshi, N. 2016. Identification of butanol tolerant genes in Lactobacillus mucosae [abstract]. American Society for Microbiology.
Technical Abstract: Butanol, though in low concentrations, is produced biologically through fermentation of lignocellulosic biomass-derived substrates by Gram-positive Clostridium species. However, naturally available butanol fermenting microbes are sensitive to stress caused by increased production of butanol and the presence of various inhibitors from biomass hydrolyzates. Thus for commercial production, new strains with better tolerance to butanol and inhibitors are desired. One strategy is to genetically modify available species of Clostridium by introducing stress tolerance genes. The rationale of this study is to seek butanol tolerance genes from other Gram-positive species which might be better suited than those from the Gram-negative Escherichia coli or eukaryotic Saccharomyces cerevisiae. Several butanol tolerant Lactobacilli were found capable of growth in 3-4% butanol after long term adaptation. In this study, Lactobacillus mucosae BR0605-3was used to identify new butanol tolerance genes, since this strain showed most robust growth in 4% butanol and the genome sequence of L. mucosae is publically available. Total cellular proteins from duplicate cultures of L. mucosae BR0605-3 grown in MRS with 0 and 4% butanol were extracted and subjected to 2D-gel electrophoresis. Comparisons of 2D gel images between 0% and 4% butanol grown cultures indicated expression levels changed in response to growth in 4% butanol. Both increases and decreases of individual spots were measured and calculated from the intensity on the gel images. Based on the significance and multitude of changes, 50 spots were chosen and analyzed using LC-MS/MS and a total of 31 protein spots were identified either from the L. mucosae database through ProteinLynx Global Server (PLGS) or from the Mascot database through NCBI and SwissProt. The identification of butanol stress related proteins will be presented and the results will help us to understand the molecular mechanisms governing tolerance to high butanol concentrations. This study will lead to cloning of specific genes related to butanol tolerance, which may be used for improving biocatalysts for efficient conversion of biomass to biofuel butanol.