Proteomic analysis identifies dysregulated proteins in butanol-tolerant gram-positive Lactobacillus mucosae BR0713-33

Authors: Liu, Siqing; Qureshi, Nasib; BISCHOFF, KENNETH - Former ARS Employee; DARIE, COSTEL - Clarkson University

Submitted to: ACS Omega
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2021
Publication Date: 1/28/2021
Citation: Liu, S., Qureshi, N., Bischoff, K., Darie, C.C. 2021. Proteomic analysis identifies dysregulated proteins in butanol-tolerant gram-positive Lactobacillus mucosae BR0713-33. ACS Omega. 6(5):4034-4043. https://doi.org/10.1021/acsomega.0c06028.
DOI: https://doi.org/10.1021/acsomega.0c06028

Interpretive Summary: Butanol is an alternative biofuel that can be produced biologically through fermentation of agricultural feedstocks by Gram-positive Clostridium species. For economic feasible production, increased butanol fermentation titers are desired; however, currently available butanol producing microbes are severely inhibited by high butanol concentrations. To increase Clostridium strains' butanol tolerance, obtain high concentrations in fermentation broth, and achieve cost-effective bioproduction it is essential to understand butanol inhibition mechanisms at the molecular level. Here we reported the identification of butanol tolerance genes in a butanol tolerant Gram-positive bacterium. These results can be used as guidance for better targeted engineering strategies to improve tolerance and increased bioproduction of butanol.

Technical Abstract: Butanol can be produced biologically through fermentation of lignocellulosic biomass derived sugars by Gram-positive Clostridium species. For cost-effective production, increased butanol fermentation titers are desired. However, currently available butanol fermenting microbes do not tolerate sufficiently high butanol concentrations, thus, new butanol tolerant strains are desired for a profitable production. One promising strategy is to genetically modify Clostridium by introducing stress tolerance associated genes. This study was aimed to seek butanol tolerance genes from other Gram-positive species which might be better suited than those from Gram-negative E. coli or eukaryotic Saccharomyces cerevisiae. Several butanol tolerant lactobacilli were reported previously and Lactobacillus mucosae BR0713-33, which showed the most robust growth in 4% butanol, was used here for proteomics analyses. Proteins were identified that are dysregulated in response to increased concentrations of butanol in L. mucosae. These results can help guide targeted engineering strategies to improve tolerance and production of biobutanol.