Tuesday, April 20, 2010
LL Conference Facility (Hilton Clearwater Beach)
Improving condition and efficiency of biomass pretreatment is necessary for reducing the production cost of lignocellulosics-based biofuel. The wood-feeding termite selected by nature to utilize wood as a sole food source is capable of degrading wood-cellulose in hours instead of weeks as in fungal and bacterial systems, which has great significance for biological pretreatment. In this study, we propose a hypothesis that the high efficiency of cellulose utilization by termites is influenced not only by their active cellulase system, but also by other factors involved in lignin pretreatment before hindgut. We employed series analysis including pyrolysis-gas chromatography/ mass spectrometry, fourier transform-infrared, gas chromatography/ mass spectrometry, high performance liquid chromatography, thermogravimery analysis, tetramethylammonium hydroxide thermochemolysis, 13C and 1H liquid nuclear magnetic resonance, and transmission electron microscopy to measure lignin modification/degradation in different gut-sections of selected lower termite Coptotermes formosanus. Different substrates (softwood, lignin model dimers with different specific linkages, lignin sulfonates, kraft lignin, milled wood lignin, lignase indicator, organic dyes, and polycyclic aromatic hydrocarbons) were studied. Meanwhile, micro-environmental conditions of different gut-segments were analyzed using microsensors that specially designed for determining the distribution of oxygen, redox potential, and pH value. The results demonstrate that lignin modification by termite starts from the foregut and occurs mainly in the midgut region, which is supported by micro-environments in different gut-segments. With a fundamental understanding of lignin-disruption mechanism and the facilitated microenvironment conditions, the study contributes scientific knowledge on biomass pretreatment by wood-feeding termite, which can be applied to improve biomass conversion technologies.