title: Ionic liquid-tolerant microorganisms and microbial communities for lignocellulose conversion to bioproducts.
abstract: Chemical and physical pretreatment of biomass is a critical step in the conversion of lignocellulose to biofuels and bioproducts. Ionic liquid (IL) pretreatment has attracted significant attention due to the unique ability of certain ILs to solubilize some or all components of the plant cell wall. However, these ILs inhibit not only the enzyme activities but also the growth and productivity of microorganisms used in downstream hydrolysis and fermentation processes. While pretreated biomass can be washed to remove residual IL and reduce inhibition, extensive washing is costly and not feasible in large-scale processes. IL-tolerant microorganisms and microbial communities have been discovered from environmental samples and studies begun to elucidate mechanisms of IL tolerance. The discovery of IL tolerance in environmental microbial communities and individual microbes has lead to the proposal of molecular mechanisms of resistance. In this article, we review recent progress on discovering IL-tolerant microorganisms, identifying metabolic pathways and mechanisms of tolerance, and engineering microorganisms for IL tolerance. Research in these areas will yield new approaches to overcome inhibition in lignocellulosic biomass bioconversion processes and increase opportunities for the use of ILs in biomass pretreatment.
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, One Shields Ave., Davis, CA, 95616, USA.
authors.forename: Chaowei
authors.initials: C
authors.lastname: Yu
authors.affiliation: Joint BioEnergy Institute, Emeryville, CA, 94608, USA.|Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors.forename: Blake A
authors.initials: BA
authors.lastname: Simmons
authors.affiliation: Joint BioEnergy Institute, Emeryville, CA, 94608, USA.|Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Singer
authors.affiliation: Joint BioEnergy Institute, Emeryville, CA, 94608, USA.|Biosciences Division, Lawrence Livermore National Laboratory, Livermore, CA, 94551, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Thelen
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, One Shields Ave., Davis, CA, 95616, USA. jsvander@ucdavis.edu.|Joint BioEnergy Institute, Emeryville, CA, 94608, USA. jsvander@ucdavis.edu.
authors.forename: Jean S
authors.initials: JS
authors.lastname: VanderGheynst
mesh_terms: D056804:Biofuels; D001688:Biological Products / Q000378:metabolism*; D001711:Biotransformation; D004352:Drug Resistance, Microbial; D052578:Ionic Liquids / Q000633:toxicity*; D008031:Lignin / Q000378:metabolism*; D059013:Microbial Consortia; D012997:Solvents / Q000633:toxicity*
chemical_list: D056804:Biofuels; D001688:Biological Products; D052578:Ionic Liquids; D012997:Solvents; C036909:lignocellulose; D008031:Lignin
keywords: Engineering ionic liquid tolerance; Ionic liquid pretreatment; Ionic liquid tolerance; Microbial community enrichment