高效秸秆厌氧降解复合菌系的构建及功能菌株的筛选

QIBEBT-IR > 工业生物燃气研究组

	高效秸秆厌氧降解复合菌系的构建及功能菌株的筛选
	匡小珠
导师	邱艳玲
	2010-05
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位专业	生态学
关键词	秸秆沼气厌氧微生物 Dgge
其他摘要	秸秆不能被大规模用于沼气生产的主要问题是产气速率较慢。根本原因在于秸秆本身速效养分低，木质纤维素含量高。研究秸秆沼气发酵各阶段关键功能菌，建立秸秆沼气发酵微生物群落选育技术，驯化培养高效秸秆厌氧降解复合菌系对提高秸秆沼气工程效率具有重要意义。本研究以秸秆为唯一碳源进行驯化培养共获得 6 组中温厌氧秸秆降解复合菌系。对其中 2 组复合菌系 WS-H 和 RL 进行了秸秆降解效率实验，结果表明，经过 77 天培养，两者秸秆总固体含量（TS）去除率分别为 31.9%和 23.7%，复合菌系 WS-H 对纤维素和木质素的去除率分别为 54.9%和 38.0%，而半纤维素几乎没有降解；复合菌系 RL 对纤维素和半纤维素的去除率分别为 38.2%和 19.4%，木质素几乎没有降解。运用 16S rRNA genePCR-DGGE（变性梯度凝胶电泳）对复合菌系进行了分子生物学解析，结果显示不同环境来源的秸秆降解复合菌系的优势种群差别较大。以秸秆降解菌大量存在的自然和人工环境为分离源，运用亨盖特厌氧滚管技术对秸秆降解各阶段的功能菌进行了分离培养。获得了 2 株新属水平中温厌氧糖类发酵性细菌（NM7和 NM5）。菌株 NM7 的 16S rRNAgene 序列与菌株 Paludibacter propionicigenes WB4T（分布于紫单胞菌科）同源性最高，相似性为 91.6%；菌株 NM5 的 16S rRNA gene 序列与菌株Chthoniobacter flavus Ellin428（分布于疣微菌门）同源性最高，相似性为 90.109%，通过生理生化特性鉴定和 16S rRNA gene 系统发育树分析表明菌株 NM7 和菌株 NM5 分别代表紫单胞菌科和疣微菌门新属水平菌株，目前菌株 NM7 已在相关保藏机构进行保藏。此外，分离到 3 株氢气营养型的伊万诺夫氏甲烷杆菌、1 株已知中温厌氧梭菌属纤维素降解菌、3株分别分布于梭菌属或拟杆菌属的中温、厌氧木聚糖降解菌。; Slow biogas production is the main problem of Straw-biogas project as a large-scale. The root cause is low available nutrient and high cellulose content of wood of straw itself. Therefore, it is meaningful to improve the efficiency of straw-biogas project by studying the key functional bacteria and establishing the screening technology of microbial community for efficient anaerobic straw-degradation. In this paper, six groups of straw-degrading anaerobic microbial system were screened by adding corn straw as the sole carbon resource, and the mocribial system named WS-H and RL were chosed to study their corn-degrading function. Results showed that the total removal efficiency(TS) of corn straw by the WS-H were 31.9% with its cellulose content decreased by 54.9% and lignin by 38.0%, while by the RL were 23.7% with its cellulose content decreased by 38.2% and hemicellulose by 19.4% after 77 days anaerobic digestion. It is concluded that the dominant strains after domestication differentiate greatly combining the DGGE (denatured gradient gel electrophoresis) results of partial 16S rRNA gene fragment of the two microbial system.In addition, morn than 20 species of mesophilic anaerobes were isolated by Hungate anaerobic technologue from several natural or artificial habitats, in which were abundant straw-degrading microorganism. Two novel genus of fermentative anaerobes, strain NM7T and NM5T were physiologically and phylogenetically characterized. Phylogenetic analysis based on the 16S rRNA gene sequence data showed that strain NM7T has low sequence similarity of 91.6% to its closest recognized strain Paludibacter propionicigenes WB4T (ascribed to the phylum ‘Bacteroidetes’), and strain NM5T has also low sequence similarity of 90.126% to its closest recognized strain Chthoniobacter flavus Ellin428T (ascribed to the phylum ‘Verrucomicrobia’). On the basis of the physiological and phylogenetical data, strain NM7T and NM5T represent novel genus of phylum ‘Bacteroidetes’, ‘Verrucomicrobia’ respectively. Besides, one isolate of cellulytic anaerobe was ascribed to species of clostridium, three others of xylan-degrading anaerobes were ascribed to species of clostridium or bacteroides, still three of methanogens was charaeterized to be Methanobacterium ivanovii with a high 16S rRNA gene sequence similarity of 100%.
作者部门	生物制氢与沼气团队
学科领域	生物制氢与沼气
公开日期	2011-08-30
学位类型	硕士
语种	中文
文献类型	学位论文
条目标识符	http://ir.qibebt.ac.cn/handle/337004/332
专题	工业生物燃气研究组
推荐引用方式 GB/T 7714	匡小珠. 高效秸秆厌氧降解复合菌系的构建及功能菌株的筛选[D]. 北京. 中国科学院研究生院,2010.

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