Potential of termite-based biomass pre-treatment strategies for use in bioethanol production

When considering the current state of the biorefinery industry, it is readily apparent that industrial cellulose and hemicellulose digestion processes are relatively advanced, whereas enzymatic pre-treatment strategies for biomass delignification and cellulose solubilization are not well developed. The need for efficient biomass pre-treatment strategies presents a significant opportunity for researchers studying lignocellulose digestion in termites and other insects. With an emphasis on industrial biomass pre-treatment, this review provides an overview of: (i) industrial biorefining operations (feedstocks, processing, and economics); (ii) recent findings from termite research that have revealed candidate enzymes; and (iii) research needs and opportunities for consideration by entomologists working in this area. With respect to research findings, recently identified candidate lignases (laccases, catalases, peroxidases, esterases), other potentially important detoxification enzymes (cytochrome P450, superoxide dismutase), and phenolic acid esterases (carboxylesterases) that may assist in hemicellulose solubilization are overviewed. Regarding research needs and opportunities, several approaches for identification of candidate pre-treatment enzymes from upstream, symbiont-free gut regions are also described.