一株反硝化细菌的分离鉴定及其反硝化特性

从处理城镇污水的移动床生物膜反应器中分离获得一株反硝化细菌D3，并进一步研究该菌株的系统发育地位及反硝化特性。采用16S rDNA序列分析对菌株进行初步鉴定，探讨了基质浓度、起始pH和温度对菌株反硝化活性的影响。根据形态学特征、生理生化特性及16S rDNA序列测定分析，初步鉴定菌株属于寡养单胞菌属。该菌能利用硝酸钠或亚硝酸钠进行反硝化作用，最佳电子受体是硝酸盐氮，反硝化速率最大为19.86 mg/（L·h），最适生长pH为7.36，最适生长温度为33.5℃。菌株D3在初始硝态氮浓度为140 mg/L，以乙酸钠为惟一碳源，pH为7.36，温度33.5℃的最优生长条件下，培养10 h进入对数生长期，倍增时间为9.9 h，48 h内硝酸盐还原率达95%。

Identification and denitrification characteristics of a denitrifier

A denitrifier named D3 was isolated from a moving bed biofilm reactor treating municipal wastewater.Phylogeneticaffiliation and denitrification characteristicsof the strain were further studied. 16S rDNA sequence was analyzed to identify the strain. Effects of substrate concentration, pH and temperature on the denitrification activity of the strain were studied. Strain D3 was identified as Stenotrophomonas sp. through morphological feature, biochemical/biophysical characteristics and 16S rDNA sequence analysis. Strain D3 was able to use either sodium nitrate or sodium nitrite as electron acceptor to oxidize organic matter. The optimal electron acceptor was nitrate, the maximum denitrification rate was 19.86 mg/(L·h). The optimal pH and temperature for D3 were 7.36 and 33.5℃. Under the optimal conditions ( NO3--N 140 mg/L, acetate served as sole organic carbon source, pH 7.36 and 33.5℃), strain D3 in the exponential phase was obtained after 10 h, and the doubling time was 9.9 h. The nitrate removal efficiency was up to 95% in 48 hours.