Lignocellulose Degradation by Termites

Abstract

Termites (Insecta: Isoptera) are imperative terrestrial decomposers as they feed on lignocellulosic plant materials such as decaying wood, grass, animal dung or plant litter at various stages of humification. They are dependent on the microbes of their gut for digestion of complex polysaccharides of the wood into simpler molecules. Cellulose is a major polymeric carbohydrate present in the wood which is broken down to simpler byproducts through metabolic steps by the hind-gut microbes Termite gut microbes also produce gasses during cellulose degradation process of which methane is a major product. Gut microbes belong to three major groups namely, bacteria, archaea and protozoa, show a mutualistic relationship and typically convert 95% of cellulose into simple sugars within 24 hours. More than 200 species of microbes form this community and produce different types of wood-busting enzymes mainly cellulases, cellubiases, hemicellulases, glucosidases and gluconases during wood degradation. Studies suggest that lower termites utilize both endogenous and protozoal enzymes for cellulose digestion while higher termites acquire enzymes from their diet instead of protozoal enzymes. Some termite species change their feeding habits with seasonal variations which affect population of the gut microbes and therefore, are responsible for enhancing their survival efficiency under changed environmental conditions.Key words: Termites, gut, microbes, cellulose, enzymes.