Endoglucanase production was carried out using in-house isolate Aspergillus terreus on rice straw under
solid state fermentation. An increase of 1.25-fold endoglucanase production was obtained under optimized
conditions using response surface methodology. The enzyme was purified to homogeneity by gel
filtration chromatography. Its molecular weight was determined as 28.18 kDa by gel filtration and
29.13 kDa on SDS-PAGE. The enzyme displayed maximum activity at 50 C and pH 4.8. It was stable for
240 min at 50 C and 120 min at 60 C but rapidly inactivated at 70 C. The purified enzyme was specific
towards carboxymethyl-cellulose but showed no activity for cellobiose or xylan. Maximum velocity
(Vmax) and KM were 16.15 mmol min1 mg1 and 12.01 mg ml1, respectively. AgNO3, KCl, NaCl, and
MnSO4 were found to inhibit enzyme activity while CaCl2 and ZnSO4 activated the enzyme. Internal
peptide mass fingerprinting analysis identified that the protein belongs to GH12 superfamily endoglucanases.
External supplementation of the purified enzyme to the crude cellulase showed 38.7% increase
in saccharification efficiency of the delignified rice straw compared to the crude cellulase alone. The
results demonstrated that the addition of GH 12 family purified endoglucanase to the crude cellulase can
efficiently convert lignocellulosic biomass to fermentable sugars.