鸡粪沼气池产甲烷菌多样性

Methanogenic Diversity in an Anaerobic Digester with Chicken Feces

摘要:

采用分子生物学方法构建16S rDNA基因文库, 研究鸡粪沼气池发酵液中产甲烷菌的菌群结构。随机分析文库中50个克隆的16S rDNA基因序列, 结果发现, 其中46个克隆属于产甲烷菌属, 与Methanogenium marinum strain AK-1菌株的相似性为99%-100%, 占总数的92%; 3个克隆(KD525、KD526和KD567)属于甲烷袋状菌属, 与Methanoculleus sp. dm2菌株的相似性均为99%, 占总数的6%; 1个克隆(KD519)属于甲烷粒菌属, 与Methanocorpusculum bavaricum菌株的相似性为99%, 占总数的2%。另外, 同样分析了样品中甲基辅酶M还原酶alpha亚基mcrA基因氨基酸序列的差异。气相色谱法分析结果显示, 发酵液中甲酸含量为28.85 g/L, 约占总有机酸含量的81.7%; 沼气的主要成分为甲烷、二氧化碳和氢气, 分别约占总气体量的55.5%、41.1%和3.2%。

Abstract:

Methanogenic diversity was characterized in an anaerobic digester with chicken feces by using a culture-independent approach. 50 clones of a 16S rDNA gene library were randomly selected and their sequences were phylogenetically analyzed. 46 of them (92%) was determined belonging to Methanogenium with similarities to Methanogenium marinum strain AK-1 between 99% to 100%; 3 clones (6%), KD525, KD526, and KD567, belonging to Methanoculleus with similarities 99% to Methanoculleus sp. dm2; one clone (2%), KD519, belonging to Methanocorpusculum with a similarity 99% to Methanocorpusculum bavaricum. Further more, the phylogenetic analyse of alpha subunit A of methyl-coenzyme M reductase (mcrA) clones were also performed. Gas chromatography assay showed that the content of formic acid was 28.85 g/L, 81.7% of the total volatile fatty acid of the fresh fermentation slurry; and the produced biogas from the digester was also determined, mainly composing of methane (55.5%), carbon dioxide (41.1%), and hydrogen (3.2%).