Enzyme activity in dialkyl phosphate ionic liquids

The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariellavolvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v.

► β-Glucosidase derived from Volvariellavolvacea showed good activity in up to 10% v/v ionic liquids.
► Metagenomic enzymes also showed good to excellent activity in up to 10% v/v ionic liquids.
► The activity of xylanase and arabinofuranosidases were enhanced in the dimethyl phosphate ionic liquids.
► In general, the enzymes were deactivated in greater than 10% v/v 1-ethyl-3-methylimidazolium diethyl phosphate.
► The results indicate that extensive washing of biomass after ionic liquid pretreatment may not be necessary.