Physiochemical lignocellulose modification by the Formosan subterranean termite Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) and its potential uses in the production of biofuels

Abstract

Formosan subterranean termites (Coptotermes formosanus Shiraki) and other wood-feeding insects have the ability to digest cellulose and structurally modify or degrade lignin. We examined the physical and chemical changes to lignocellulosic components of Chinese red pine (Pinus massoniana) after passing through the termite (C. formosanus) digestive system. The purpose of this research was to evaluate biochemical digestive processes in the C. formosanus gut as potential models for biofuels processing. Results suggest that demethylation, demethoxylation, and propyl side-chain modification are responsible for higher lignin removal and cellulose crystallinity reduction after structural alteration. SEM images also further indicated that unlike the fungus- growing termites Odontotermes formosanus, the lower termites C. formosanus disrupted the lignocellulose structure, and thus resulted in an increase of surface area to cellulase. Comparative enzymatic hydrolysis tests between raw wood and C. formosanus faeces revealed an enhanced level of enzymatic digestibility in digested material. Based on the results, C. formosanus can efficiently modify lignin at ambient temperatures and pressures in contrast to current methods used in biofuels production.