一株低温产甲烷菌的筛选分离与系统发育分析研究

Isolation and Phylogenetic Analysis of a Psychrophilic Methanogen

采用厌氧分离技术从新疆越冬沼气池分离出一株产甲烷菌株SZ-3,该菌株5～40℃范围内均能生长,其生长pH范围4～8,符合低温兼性嗜冷产甲烷菌筛选要求;该菌株最适生长温度20℃,生长最适pH值为7,最适NaCl浓度为0～0.4mol/L;该菌株革兰氏染色阳性,菌落呈黄色,显微镜观察为不规则球状,菌体聚集且不规则裂殖。菌株只能利用甲醇、H2CO2(80∶20)混合气、甲胺、二甲胺,三甲胺,不能利用甲酸、乙酸等生长;16SrDNA序列分析,SZ-3菌株和产甲烷八叠球菌属同源性最高为99%,系统发育分析和生理生化特征研究表明此菌株为甲烷八叠球菌属湖沉积产甲烷八叠球菌种(Methanosarcina lacustris)。

A methanogen SZ-3 with growth temperature of 5~40℃,pH 4~8 and optimal growth conditions： 20℃,pH 7.0,0~0.4 mol/L NaCl,was isolated from the winter biogas digester of Xinjiang,by anaerobic screening technique,consistent with low temperature and the amphipsychrophilic methanogens screening requirements.The strain was gram-positive,irregular spherical,cell aggregation,and irregular fission.This strain could use hydrogen and carbon dioxide（80∶20）,or methylamine,dimethylamine,trimethylamine,methanol as substrates for its growth and methanogenesis,but it could not use formate acid and acetic acid.Sequence analysis of the 16S rRNA genes of strain SZ-3 and Methanosarcina revealed that the similarity reaches to 99%.Phylogenetic analysis and physicobiochemical characteristics show that strain SZ-3 belongs to Methanosarcina lacustris.