| Summary: | 碩士 === 國立中央大學 === 生命科學研究所 === 100 === Anaerobic digestion (AD) is a biological treatment using a wide range of organic wastes, such as animal manure and organic solid waste to produce biogas. Biogas, a mixture of methane and carbon dioxide, is a renewable source of energy. AD can be divided into three major stages: hydrolysis, acidogenesis and methanogenesis. This study was aimed to research structures and functions, using cultivation-dependent and cultivation-independent (clone library and DGGE) methods, of the microbial community in AD at 55°C using pig manure. Based on phylogenetic analysis of 16S rRNA genes, the isolated microbes include 95% Firmicutes, 5% Proteobacteria. The clone libraries indicated that the bacterial community was composed of 54% Proteobacteria, 38% unclassified bacteria and 7% Firmicute. The archaeal community was composed of 79% Methanobacteriaceae, 17% Methanosarcinaceae and 4% unclassified Euryarchaea. The denaturing gradient gel electrophoresis (DGGE) revealed 13 dominant bacterial bands that belonged to the bacteria phyla 50% Firmicute, 40% Proteobacteria and 10% unclassified bacteria. The 7 dominant archaeal bands were composed of 14% Methanobacteriaceae. The diverse species from the phyla Firmicutes and Proteobacteria play key roles in the hydrolysis and acidogenesis stages of degrading the complex organic matters in swine manure. Species from Methanobacteriaceae and Methanosarcinaceae are proved to be able of using H2 and CO2 to produce methane. In addition, Methanosarcinaceae species also use acetate as a substrate to produce methane. This study provides information on the microbial community in thermophilic AD using swine manure as the sole feedstock for the biosynthesis of biogas.
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