Cellulolytic activity of gut extract of subterranean termite, Odontotermes obesus Rambur: A pretreatment tool for conversion of lignocellulosic biomass to fermentable sugar for biorefinery industry

Abstract

Lignocellulosic biomass is a chief and cheap raw material for bioethanol production. However, pretreatment is a critical and most expensive step in lignocellulosic biomass to biofuel conversion. Biological pretreatments offer an alternative for lignocellulosic biomass conversion using enzyme hydrolysis. Termites are well known for the ability to digest lignocelluloses, using it as a sole food source. To effectively digest ligonocellulose/wood, termites produce an array of enzymes along with the help of microbial and protist symbionts. Subterranean termite, like Odontotermes obesus, devoid of protist symbiont in their hind gut capable of digesting cellulose using endogenous cellulases produced naturally by them. The cellulolytic activity of gut extracts of O. obesus was evaluated with commercially available carboxymethylcellulose (CMC) for their efficacy in conversion of cellulose to fermentable sugar. It is found that the gut extracts of O. besus potentially convert 49 to 75% of CMC into glucose. Hence, we look for novel hydrolytic enzymes in the gut extracts of O. obesus for efficient conversion of lignocellulosic biomass to fermentable sugars.

Key words: Termite gut, Odontotermes obesus, enzymes, lignocelluloses, hydrolytic enzymes.