Termite Hindgut Bacteria TAV5: Key to Lignocellulose Waste Decomposition

Abstract Description: Bioenergy from lignocellulose biomass is one of the most promising candidates to help move towards a fossil fuel free future. The Department of Energy estimates that 104 million tons of agricultural waste can be sustainably harvested each year to provide a renewable domestic source of energy. Agricultural waste can have lignocellulose content of up to 90%. Unfortunately , lignin is resistant to microbial attack under low oxygen conditions which normally occur in landfills, and it often shields lignocellulose components (cellulose and hemicellulose) from decomposition as well. Termite gut bacteria has been proven to degrade lignin boosting methane production from lignocellulose waste.

Lab tests were conducted in batch-scale reactors (125 mL) with four kinds of agriculture waste i.e., rice husk, rice straw, wheat straw and corn stover to determine the optimal ratios of TAV5 to anaerobic digester (AD) microorganisms. Based on batch tests, optimal ratios of TAV5 to AD microorganisms were found to be 30% for rice straw, wheat straw and corn stover and 60% for rice husk. Addition of TAV5 increased methane production from rice husk, rice straw, wheat straw and corn stover, by 19%, 71%, 43% and 55%, respectively.

Based on these results 8 pilot scale digesters (275 gallon) were started, containing all 4 types of agricultural waste. Four of the digesters were seeded with TAV5 whereas others were used as controls. The digesters are still operational, and we will have the data from them to present at the conference.