不同碳源促进污染水体氮素转化的微生态过程

在试验条件下,向氮污染河道水体中C/N按15∶1补加甲醇、乙醇、乙酸钠、柠檬酸钠、葡萄糖、蔗糖、麦芽糖、羧甲基纤维素钠,检测水体氨氮、亚硝酸盐、硝酸盐、总氮的变化,以及在此过程中水体细菌胞外酶活性、细菌群落结构的变化。结果显示,除甲醇、羧甲基纤维素钠外,补加有机碳源显著降低了水体氨氮的含量,水体β-葡萄糖苷酶活性在碳源补加后快速增加,补加葡萄糖、蔗糖、麦芽糖的水体中细菌群落结构明显异于其他处理,表明添加有机碳源可显著加快污染水体中氮素的转化,水体微生物在此过程中起到关键作用。水体细菌群落结构和代谢活性对不同类型有机碳源有着不同的响应,因而添加不同有机碳源对水体氮素转化具有不同的促进作用。

Microbial ecological process of nitrogen transformation accelerated by different organic carbon in polluted water

In the present study, methanol, ethanol, sodium acetate, sodium citrate, glucose, sucrose, maltose, and CMC-Na was added in nitrogen-polluted urban river water with C/N of 15∶1. Variation of ammonia, nitrite, nitrate, total nitrogen were detected by national standard method, β-glucosidase activity were determined using the fluorogenic model substrates, and the change of bacterial community structure were analyzed by PCR-DGGE. It was shown that contents of ammonia decreased significantly after organic carbon sources addition except methanol or CMC-Na. Addition of organic carbon sources increased β-glucosidase activity. Bacterial community structure differed obviously with addition of glucose, sucrose and maltose. The results indicated that addition of organic carbon could accelerate transformation of nitrogen in the nitrogen-polluted water, in which microbes played key role. Bacterial community and metabolic activity had different responses to varied organic carbons, which would lead to different strength on nitrogen transformation acceleration.