Mechanism of imidazolium ionic liquidstoxicity in Saccharomyces cerevisiae and rationalengineering of a tolerant, xylose-fermenting strain

Microbial Cell Factories

Research

Jeff S. Piotrowski¹  Scott Bottoms¹  Li Hinchman¹  Sean McIlwain¹  Quinn Dickinson¹  Trey K. Sato¹  Alexander Hebert²  Joshua J. Coon²  Robert Landick³  Chad L. Myers⁴  Sheena Li⁵  Charles Boone⁶ 

[1] DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, 53726, Madison, WI, USA;DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, 53726, Madison, WI, USA;Biomolecular Chemistry, University of Wisconsin, Madison, WI, USA;DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, 53726, Madison, WI, USA;Departments of Biochemistry and Bacteriology, University of Wisconsin, Madison, WI, USA;Department of Computer Science and Engineering, University of Minnesota-Twin Cities, Minneapolis, MN, USA;RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan;Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada;

关键词: Chemical genomics;    Ionic liquids;    Lignocellulosic;    Biofuel;    Biocatalysts;   

DOI  :  10.1186/s12934-016-0417-7

 received in 2015-09-17, accepted in 2016-01-08,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundImidazolium ionic liquids (IILs) underpin promising technologiesthat generate fermentable sugars from lignocellulose for future biorefineries.However, residual IILs are toxic to fermentative microbes such as Saccharomyces cerevisiae, making IIL-tolerance akey property for strain engineering. To enable rational engineering, we usedchemical genomic profiling to understand the effects of IILs on S. cerevisiae.ResultsWe found that IILs likely target mitochondria as their chemicalgenomic profiles closely resembled that of the mitochondrial membrane disruptingagent valinomycin. Further, several deletions of genes encoding mitochondrialproteins exhibited increased sensitivity to IIL. High-throughput chemicalproteomics confirmed effects of IILs on mitochondrial protein levels. IILsinduced abnormal mitochondrial morphology, as well as altered polarization ofmitochondrial membrane potential similar to valinomycin. Deletion of theputative serine/threonine kinase PTK2 thoughtto activate the plasma-membrane proton efflux pump Pma1p conferred a significantIIL-fitness advantage. Conversely, overexpression of PMA1 conferred sensitivity to IILs, suggesting that hydrogen ionefflux may be coupled to influx of the toxic imidazolium cation. PTK2 deletion conferred resistance to multipleIILs, including [EMIM]Cl, [BMIM]Cl, and [EMIM]Ac. An engineered,xylose-converting ptk2∆ S. cerevisiae (Y133-IIL) strain consumed glucoseand xylose faster and produced more ethanol in the presence of 1 % [BMIM]Cl thanthe wild-type PTK2 strain. We propose a modelof IIL toxicity and resistance.ConclusionsThis work demonstrates the utility of chemical genomics-guidedbiodesign for development of superior microbial biocatalysts for theever-changing landscape of fermentation inhibitors.

【 授权许可】

CC BY   
© Dickinson et al. 2016