Development of tailor-made synergistic cellulolytic enzyme system for saccharification of steam exploded sugarcane bagasse

Abstract

Designing a tailor-made synergistic system is a promising strategy for developing an effective enzyme for saccharification of lignocellulosic materials. In this study, a cellulolytic enzyme mixture comprising selected core recombinant enzymes for hydrolysis of sugarcane bagasse pretreated by alkaline-catalyzed steam explosion was optimized using a mixture design approach. The optimized enzyme system comprised a cellobiohydrolase (Cel7A) from Talaromyces cellulolyticus, an endo-glucanase (Cel7B) from Thielavia terrestris, a β-glucosidase (BGL) and an endo-β1,4-xylanase (XYN) from Aspergillus aculeatus at the ratio of 0.34:0.27:0.14:0.25. The maximum reducing sugar yield of 797 mg/g biomass, comprising 543 and 96.8 mg/g glucose and xylose, respectively were achieved, equivalent to 92.44% and 47.50% recoveries, respectively from the pretreated substrate at the enzyme dosage of 20 mg/g biomass. The sugar yield from the quaternary enzyme mixture was 17.37% higher than that obtained with Accellerase 1500.

Keywords: Biorefinery; Glycosyl hydrolase; Lignocellulose; Mixture design; Synergy.