Deep eutectic solvents compatible Aspergillus niger cellulase and its utility forinsitu pre-treatment and sacc harification of wheat straw

Abstract

Deep eutectic solvents (DES) represent an emerging class of ionic liquids with many novel properties and wide industrial applications. Very recently, they are being used as natural solvent systems for lignocellulosic biomass pre-treatment. The present study deals with the stability of Aspergillus niger cellulase in three types of DES namely reline (choline chloride and urea), glyceline (choline chloride and glycerol) and ethaline (choline chloride and ethylene glycol) at high concentrations (70%, v/v). The tertiary structural changes in the presence of varying concentrations of DES were monitored by intrinsic fluorescence indicating the maintenance of active site of cellulase in the presence of DES. Further, the applicability of DES stable cellulase was checked for the in situ pre-treatment and saccharification of wheat straw. The maximum reducing sugars (~16mg/ml) were generated under the optimised conditions by using ethaline as the chosen DES. Thus, the pre-treatment of wheat straw using DES compatible cellulase in a one-pot process represents an economical feasible approach in the utilisation of lignocellulosic biomass for the generation of biofuels.