不同环境条件下Pseudomonas sp.脱氮特性及功能基因表达差异研究

从活性污泥中分离获得一株PCL降解菌，经形态学和16S rDNA鉴定后命名为Pseudomonas sp.JQ-H3.经过脱氮实验验证，该菌能够以PCL为唯一碳源，分别以氨氮或硝酸盐氮为氮源进行异养硝化好氧反硝化.该菌能够在36h内去除93.11%的氨氮（初始氨氮浓度为102.41mg/L），氨氮最大降解速率为5.77mg/（L·h）；并且能够在48h内去除93.93%的硝酸盐氮（初始氨氮浓度为99.01mg/L），硝酸盐氮最大降解速率为4.12mg/（L·h）.对PCL膜的降解实验结果表明，菌株能够在60d内将初始重量为100mg的PCL薄膜降解94.03%，且胞外脂肪酶活性在30d时达到最大值9.18mU/mL.另外，Q-PCR实验结果表明，弱碱性环境促进了amoA和nirS基因的表达；napA、cnorB、nosZ基因的成功表达，进一步证明了菌株的异养硝化好氧反硝化能力.

Effect of environmental factors on nitrogen removal and functional genes expression of strain Pseudomonas sp

A PCL-degrading strain was isolated and identified as Pseudomonas sp. JQ-H3 through morphology observation and phylogenetic analysis. The strain showed the heterotrophic nitrification-aerobic denitrification (HN-AD) ability using PCL as a sole carbon source. About 93.11% of initial ammonium (102.41mg/L) was degraded within 36h with the maximum ammonium removal rate of 5.77mg/(L·h), while approximately 93.93% of initial nitrate (99.01mg/L) was removed within 48h with the maximum ammonium removal rate of 4.12mg/(L·h). 94.03% of PCL film with initial weight of 100mg was decomposed after 60days, and the extracellular lipases activity reached the maximum value of 9.18mU/mL at 30th days. In addition, the expression levels of amoA and nirS genes were promoted in the weak alkaline environment. The successful expression of napA, cnorB and nosZ genes further proved the HN-AD ability of the strain JQ-H3.