Increased ethanol tolerance associated with the pntAB locus of Oenococcus oeni and Lactobacillus buchneri

Authors: Liu, Siqing; Skory, Christopher - Chris; LIANG, XIAOJIN - University Of California, Davis; MILLS, DAVID - University Of California, Davis; Qureshi, Nasib

Submitted to: Journal of Industrial Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2019
Publication Date: 7/9/2019
Citation: Liu, S., Skory, C., Liang, X., Mills, D., Qureshi, N. 2019. Increased ethanol tolerance associated with the pntAB locus of Oenococcus oeni and Lactobacillus buchneri. Journal of Industrial Microbiology and Biotechnology. 46:1547-1556. https://doi.org/10.1007/s10295-019-02209-y.
DOI: https://doi.org/10.1007/s10295-019-02209-y

Interpretive Summary: Most bacteria are inhibited by the presence of alcohols, but some strains have the ability to survive high concentrations that are present in wineries and fuel ethanol facilities. Determining how these bacteria tolerate alcohol could be used to develop improved strains that can be used to produce important fermentation products in the presence of high alcohol. In this study, we compared the genomes of two alcohol tolerant bacteria, Lactobacillus buchneri and Oenococcus oeni, with other similar strains that were sensitive to the presence of ethanol. Two genes, pntA and pntB, that are often associated with stress response were identified to be unique with the alcohol tolerant isolates. These were each expressed in two other sensitive bacteria and it was found that pntB conferred a much higher tolerance to ethanol and butanol. This is the first study to show that this gene can be used to improve resistance to alcohols in other bacteria. The potential application of this work will lead to more efficient production strains that will benefit fuel ethanol producers.

Technical Abstract: Most bacteria are inhibited by the presence of alcohols, but some strains can survive high concentrations that are present in wineries and fuel ethanol facilities. We hypothesized that determining how these bacteria tolerate alcohol may allow us to develop improved strains that can be used to produce important fermentation products in the presence of high alcohol. In this study, we compared the genomes of two alcohol tolerant bacteria, Lactobacillus buchneri and Oenococcus oeni, with other similar strains that were sensitive to the presence of ethanol. Two genes, pntA and pntB, that are often associated with stress response were identified to be unique with the alcohol tolerant isolates. These were each expressed in two other sensitive bacteria and it was found that pntB conferred a much higher tolerance to ethanol and butanol. This is the first study to show that this gene can be used to improve resistance to alcohols in other bacteria. The potential application of this work will lead to more efficient production strains that will benefit fuel ethanol producers.