罗非鱼循环水养殖系统中一株肺炎克雷伯氏菌的分离鉴定及其脱氮性能研究

Identification and denitrificaition efficiency research on a strain of Klebsiella pneumoniae isolated from a tilapia recirculating aquaculture system

实验从山东德州市一罗非鱼(Oreochromis niloticus)养殖场循环水养殖系统的脱氮池中分离到一株具有高效脱氮特性的菌株(编号DZYC02),分别以葡萄糖、蔗糖、可溶性淀粉、丁二酸钠、乙酸钠、柠檬酸钠为碳源,研究了碳源种类对菌株DZYC02脱氨氮效果的影响;同时以蔗糖为碳源、NH4Cl为氮源,研究了不同碳氮比、初始pH及盐度对该菌株脱氮效果的影响。结果显示:菌株DZYC02在以柠檬酸钠为碳源、C∶N≥15、pH 5~7、盐度0~15的条件下具有良好的脱氮效果,24 h内对浓度为20 mg/L的NH+4的去除率达100%,48 h内对浓度为20 mg/L的NO-2去除率高达100%;将该菌采用浸泡方式感染斑马鱼(Danio rerio)进行生物安全试验,结果显示菌株DZYC02对斑马鱼表现出较好的安全特性。分别用Biolog细菌鉴定方法和16S rDNA序列分析比对法对该菌进行鉴定,结果显示菌株DZYC02为一株肺炎克雷伯氏菌(Klebsiella pneumoniae)。

A strain of bacteria with denitrification activity was isolated from a tilapia(Oreochromis niloticus)recirculating aquaculture system and designated as DZYC02.Carbon sources including glucose,sucrose,soluble starch,sodium succinate,sodium acetate and sodium citrate were employed to investigate the effects of carbon source on the denitrifying efficacy of strain DZYC02.Also,sodium citrate and ammonia were used as carbon and nitrogen source to evaluate the effects of C∶N,pH and salinity on the efficiency of denitrification.The results showed that the 24 h-denitrifying rate of ammonia(NH+4-N)and 48 h-denitrifying rate of nitrite(NO-2-N)were both 100%under the condition of sodium citrate being used as the carbon source,C∶N≥15,initial pH 5-7 and salinity between 0 and 15.Zebrafish(Danio rerio)were used to evaluate the biosafety of strain DZYC02 by immersion challenge,and the results showed that strain DZYC02 appeared better biosecurity for fish.The strain DZYC02 was identified as Klebsiella pneumoniae by methods of Biolog automated microbes identification system and 16S rDNA sequencing.