Monday, May 2, 2011
Grand Ballroom C-D, 2nd fl (Sheraton Seattle)
Wood-feeding termites have evolved an unique capability to digest lignocellulosic plant material with high efficiency, using it as energy and nutrition sources. This ability depends mainly on the mutualistic interaction of symbiotic gut microbiota and termite itself. This study investigated microorganisms in the midgut of termite Coptotermes formosanus, which was less described compared to the hindgut segment. We initially used fluorescence in situ hybridization (FISH) technique to visualize and identify individual bacteria and archaea in the midgut of termite, the location and ultrastructure of which associated with microvilli were examined by transmission electron microscopy (SEM). After isolation of microorganisms in the midgut through six different medium, preliminary screening was carried out on plates by testing the capabilities of oxidizing guaiacol as well as decolorizing the dye azure B. Two strains were picked out and identified as Streptomyces sp. through 16S rRNA gene sequence analysis. Liquid fermentation of two strains using softwood biomass as substrate, were further performed. The results of thermogravimetric analysis and attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy of biopretreated softwood indicated that biopretreatment can decompose the structure of softwood, optimize the thermal decomposition, and decrease the reaction temperature. The results of liquid chromatography/mass spectrometry (LC/MS) of extracellular proteins from supernatant after fermentation showed that well-known lignolytic enzymes were not detected, yet superoxide dismutase and catalase were induced dramatically.