水质净化酵母菌的分离筛选及鉴定

Isolation, screening and identification of yeast for aquaculture water purification

【目的】针对目前水产养殖专用优良菌种资源缺乏的现状,从养殖环境和养殖生物体中分离筛选具有水质净化功能的酵母菌,并对优良菌株进行鉴定。【方法】在低温和常温条件下从皮皮虾、南美白对虾肠道及养殖池底质活性污泥中分离具有水质净化功能的酵母菌,在模拟水体中对分离菌株的水质净化能力进行筛选,并对优良菌株采用形态、生理生化实验及5.8S r DNA ITS序列分析进行鉴定。【结果】从3种介质中共分离到酵母菌37株,其中常温分离16株,低温分离21株。水质净化实验结果表明,常温分离的16株酵母菌中有5株,低温分离的21株酵母菌中有6株对模拟水体中亚硝态氮和氨氮有显著的去除效果;其中低温分离的DN9和常温分离的CN6 48h能将10.64mg/L的亚硝态氮彻底转化,96h对630mg/L CODcr的去除率分别达52%和67%。DN9和CN6均产红色色素,经形态特征、生理生化特性及5.8S r DNA基因序列分析,鉴定菌株CN6为沼泽生红冬胞酵母(Rhodosporidium paludigenum),DN9为胶红酵母(Rhodotorula mucilaginosa)。【结论】红酵母DN9和CN6能有效去除养殖水体中的有机污染物和亚硝态氮,有望开发成水产养殖水质净化高效微生态制剂。

[ Objective ] In order to get excellent yeast strains for aquiculture water purification, we isolated, screened and identified yeasts from the aquacuhural environment and intestinal tract of shrimp. [ Methods ] The potential water purification ability of yeasts, isolated from the activated sludge of aquacuhural environment and intestinal tract of white shrimp and mantis shrimp under normal and low temperature, was evaluated in the simulated wastewater. Morphological physio-biochemical characteristics, 5.8S rDNA ITS gene sequence analysis were used to identify the strains. [ Results] Thirty-seven yeast strains were isolated from 3 samples, among them 16 strains were isolated under normal temperature （25℃） while 21 strains were isolated under low temperature （15℃）. Water purification test suggested 5 strains isolated under 25℃ and 6 strains isolated under 15℃ had higher removal ability of nitrite and ammonia from water. After 48 hours treatment with DN9 and CN6, 10.64 mg/L nitrite in the water was completely removed. After 96 hours treatment, CODo~ degradation rates of the 2 strains were 52% and 67% , respectively. According to morphological, physio-biochemical characteristics and 5.8S rDNA ITS gene sequence analysis, the strain DN9 was identified as Rhodotorula mucilaginosa and CN6 as Rhodosporidium paludigenum. [ Conclusion] Strains DN9 and CN6 would be promising for water purification in aquiculture.