Alcohols enhance the rate of acetic acid diffusion in S. cerevisiae: biophysical mechanisms and implications for acetic acid tolerance
Journal article, 2018

Microbial cell factories with the ability to maintain high productivity in the presence of weak organic acids, such as acetic acid, are required in many industrial processes. For example, fermentation media derived from lignocellulosic biomass are rich in acetic acid and other weak acids. The rate of diffusional entry of acetic acid is one parameter determining the ability of microorganisms to tolerance the acid. The present study demonstrates that the rate of acetic acid diffusion in S. cerevisiae is strongly affected by the alcohols ethanol and n-butanol. Ethanol of 40 g/L and n-butanol of 8 g/L both caused a 65% increase in the rate of acetic acid diffusion, and higher alcohol concentrations caused even greater increases. Molecular dynamics simulations of membrane dynamics in the presence of alcohols demonstrated that the partitioning of alcohols to the head group region of the lipid bilayer causes a considerable increase in the membrane area, together with reduced membrane thickness and lipid order. These changes in physiochemical membrane properties lead to an increased number of water molecules in the membrane interior, providing biophysical mechanisms for the alcohol-induced increase in acetic acid diffusion rate. n-butanol affected S. cerevisiae and the cell membrane properties at lower concentrations than ethanol, due to greater and deeper partitioning in the membrane. This study demonstrates that the rate of acetic acid diffusion can be strongly affected by compounds that partition into the cell membrane, and highlights the need for considering interaction effects between compounds in the design of microbial processes.

membrane permeation

carbon-14 uptake

ethanol

lignocellulose

inhibitors

n-butanol

molecular dynamics simulations

Author

Lina Lindahl

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Samuel Genheden

University of Gothenburg

Fábio Luis Da Silva Faria Oliveira

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Stefan Allard

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Nuclear Chemistry

Leif A Eriksson

University of Gothenburg

Lisbeth Olsson

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Maurizio Bettiga

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Microbial cell

2311-2638 (ISSN)

Vol. 5 1 42-55

Driving Forces

Sustainable development

Subject Categories

Cell Biology

Biochemistry and Molecular Biology

Microbiology

Areas of Advance

Energy

DOI

10.15698/mic2018.01.609

More information

Latest update

3/19/2018