Improvement of enzymatic activity of β-glucosidase from Thermotoga maritima by 1-butyl-3-methylimidazolium acetate

•β-Glucosidase gene from thermotoga was cloned and functionally expressed.•The enzyme was optimally active at pH 6.0 and 70 °C.•The effect of ionic liquids on enzyme activity was evaluated.•The enzyme demonstrated high activity in 1-butyl-3-methylimidazolium acetate.

The uses of ionic liquids (ILs) to alter the performance of enzymes and to pretreat cellulosic biomass have been investigated. In the present study, the activity of β-glucosidase from Themotoga maritima (TmBgl1A) was studied in a phosphate buffer containing imidazolium-based ILs. Among the imidazolium-based ILs that were tested, 1-butyl-3-methylimidazolium acetate [Bmim][OAc] showed the most improvement for the hydrolysis activity of TmBgl1A at pH 7.0. From the steady-state emission spectra, [Bmim][OAc] quenched the intrinsic fluorescence of TmBgl1A. The improvement in the activity of TmBgl1A induced by [Bmim][OAc] could be linked to the flexibility of the conformation of TmBgl1A.

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