一株低温降解菌的分离鉴定及其降解特性研究

Isolation,Identification and Characterization of a Low-Temperature Degrading Bacterium

从刺参（Apostichopus japonicus）养殖池塘环境中驯化分离筛选到1株低温有机物和氨氮降解菌株DB11。根据其形态特征、生理生化特性以及16S rDNA序列分析,将该菌株鉴定为马氏副球菌（Paracoccus marcusii）。经驯化,该菌株以刺参饵料为唯一营养源,低温（15℃）、低接种量（〈5×10-3）条件下能同时高效降解饵料中的有机物和氨态氮,5 d时间内对富集培养基中COD和NH4＋-N的降解率分别达50%和98%。进一步研究其降解特性表明,菌株生长适温15~30℃,生长适宜pH值为7~10,降解刺参饵料中COD和NH4＋-N的最适温度条件为15~20℃、最适pH条件为8.0~8.5;在最适降解条件下、接种量为5×10-3时,对10~20 g/L高质量浓度的刺参饵料液中COD降解效果显著,3 d时间去除率达56.9%~65.7%,对1~20 g/L质量浓度的刺参饵料液中NH4＋-N 3 d时间的去除率达91.7%~99.9%。

A low-temperature bacterium named DB11 was isolated from sea cucumber outdoor culturing ponds with high degradation of organic-pollutants and ammonia-nitrogen.Physiological and biochemical tests and the 16S rDNA sequence similarity analysis indicated that strain DB11 was similar to Paracoccus marcusii.When inoculated into the sea cucumber-feed-enrichment-medium by less than 5×10-3,strain DB11 was able to utilize 50% of COD and 98% of NH＋4-N within five days at 15 ℃.Further degradation studies showed that the appropriate range of temperature and pH value for growth of strain DB11 was 15～30 ℃ and pH 7～10,respectively,while the optimal temperature and pH value conditions for degradation of sea cucumber feed was 15～20 ℃ and pH 8.0～8.5,respectively.Strain DB11 could decompose sea cucumber feed concentration of 10～20 g/L with 56.9%～65.7% of COD degradation rate,and feed concentration of 1～20 g/L with 91.7%～99.9% of NH＋4-N degradation rate,respectively,within 3 days after inoculated by 5×10-3.