Pretreatment of lignocellulosic biomass enables more efficient enzymatic hydrolysis of cellulose and xylan to simple sugars for conversion to biofuels. Recently, ionic liquids, organic salts that are liquids at or slightly above room temperature, have emerged as promising alternatives for pretreatment.  Ionic liquids have been shown to solubilize intact biomass and facilitate more rapid enzymatic hydrolysis of biomass polysaccharides.  However, liquid retained after pretreatment inhibits enzymatic hydrolysis of the polysaccharides.  We have initiated experiments to identify ionic-liquid tolerant microbes that express lignocellulose-deconstructing enzymes that may be more tolerant of these liquids.  We have focused on using compost as the inoculum for enrichment experiments because of the diversity of lignocellulose-utilizing microbes in compost.  Aspergillus fumigatus JF-1 was enriched from cultures with 1% 1-ethyl-3-methylimdazolium acetate (Emim+OAc-), a commonly used ionic liquid, as the sole carbon source and mature compost as the inoculum.  A. fumigatus JF-1 grew with up to 5%  Emim+ OAc- as  sole carbon source, but higher concentrations of the ionic liquid were inhibitory.  When A. fumigatus JF-1 was cultured on switchgrass and corn stover, high levels of cellulase and xylanase activity were detected in the culture supernatant.  Enzymatic activities were largely retained when the assays were repeated in the presence of 5% Emim+OAc-.   We are using biochemical and proteomic methods to identify cellulases and xylanses expressed by A. fumigatus JF-1 in presence to determine if Emim+OAc- has an influence on protein expression.  We are also testing other isolates to determine if ionic-liquid tolerance is a general property of saprophytic fungi.