Degradation of the Lignocellulosic Biomass by Using a Symbiotic Bacterium in the Termite Gut

摘要

In this study, Clostridium xylanolyticum, a symbiotic bacterium in termite gut has been used to degrade the lignocellulose. To evaluate its degradation ability about the cellulose and hemi-cellulose, experiments using different substrates such as glucose, cellobiose, sodium carboxymethyl cellulose, microcrystalline cellulose AviceF PH-101, xylose, and xylan were conducted. The results showed Clostridium xylanolyticum had preference in degradation xylan. Therefore, xylan was then selected as the substrate for acclimation of the inoculum. During acclimation, the ability of xylan degradation and acid resistance were significantly improved. In follow-up substrate fermentation experiment, the first subculture was used as the inoculum for its superiorityin xylan degradation and could be reacted rapidly after one day of inoculation. In fermentation experiment of the annual Ma Bamboo, its sugar content was rapidly consumed at beginning 24 hrs, and large amount of acids, alcohol, hydrogen and carbon dioxide were produced with pH under control. Most hemi-cellulose in Ma Bamboo were almost completely used in this experiment, and 4.85 g/L of acetate, 0.14 g/L of alcohol, 99.3 mL of hydrogen and 179.6 mL of carbon dioxide were produced. Among these products,the acetate can be used as the substrate for methane fermentation, while hydrogen and alcohol can be used as the gaseous and liquid fuel, respectively.