| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 100 === Clostridium xylanolyticum, a symbiotic bacterium in termite gut, and Clostridium cellulolyticum had been found could digest hemicellulose and cellulose, respectively. The objective of this study was to evaluate the possibility of improving the utilization rate of lignocellulose and hence to increase the production of acids and alcohol through fermentation by these two species of bacteria.
Although C. cellulolyticum is an obligate anaerobe, it could be inoculated in the laminar flow hood without filling nitrogen. Only when opening the seeding bacterium ampoule and preparing the medium for activation, to maintain the anaerobic conditions by using the anaerobic glove box is necessary. It was also found that the conventional Hungate-type tube used in cultivation of C. cellulolyticum could be simply replaced by screw-cap test tubes, but similar to other obligate anaerobes, addition of reducing agent is still required.
The growth curve of C. cellulolyticum showed 9 hrs of lag phase was existed and the following exponential phase was from 9 to 20 hrs, and no stationary phase was observed. The mean generation time was 1.37 hrs and the optimal inoculation period was between 16-20 hrs. According to the previous study, cell growth of C. xylanolyticum in modified PYG medium existed a 12 hrs lag phase, exponential phase was from 12 to 30 hrs, and stationary phase was from 30 to 96 hrs. The mean generation time was found to be 2.4 hrs, and the optimal inoculation period was between 24-30 hrs.
Two fermentation tests using different substrates were conducted, artificial substrate fermentation and Ma Bamboo fermentation. In test of the artificial substrate fermentation, the products of co-culture and monoculture fermentation for both C. cellulolyticum and C. xylanolyticum had no significant difference. In monoculture of the Ma Bamboo fermentation, C. cellulolyticum presented better degradation ability about the cellulose and hemicellulose than that of C. xylanolyticum. Additionally, co-culture of the Ma Bamboo fermentation test showed better degradation ability in hemicelluloses than that of monoculture test.
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