NaOH pretreatment and enzymatic hydrolysis of Brassica juncea using mixture of cellulases

Abstract

Now a days lignocellulosic biomass based bioethanol production has been the centre of major research studies due to its varying significances. Bioethanol production by using lignocellulosic biomass as substrate is an economically feasible process. In the current study, very less concentration of sodium hydroxide was used for delignification (pretreatment) and blends of various cellulases was used for enhanced hydrolysis of carbohydrates (cellulose and hemicellulose). It was seen that most noteworthy measure of reducing sugar (40.50 mg/mL) was acquired from Brassica juncea, when it was delignified using 0.5 M sodium hydroxide at 160 °C, 10% solid loading and 30 min duration. The affectivity of above pretreatment (delignification) process was further confirmed by characterization of substrate (control and pretreated) through using SEM, XRD and FTIR. Mixture of cellulases obtained from Fusarium incarnatum KU377454 (isolated by us), Aspergillus niger MTCC284 and Trichoderma harzianum MTCC8230 was utilized for carbohydrate hydrolysis (saccharification) of delignified biomass which demonstrated highest reducing sugar production (62.35 mg/mL) at 15% solid loading, 50 °C temperature and 48 h of time duration. The current process of enzymatic hydrolysis and thermochemical pretreatment by using mixture of cellulases showed efficient reducing sugar production without the use of any costly chemicals and commercial enzymes.