一株异养硝化-反硝化不动杆菌的分离鉴定及脱氮活性

Isolation and identification of a heterotrophic nitrifying and aerobic denitrifying Acinetobacter sp．YF14 and its denitrification activity

摘要:

摘要:【目的】分离筛选并鉴定一株异养硝化－反硝化细菌，并探讨其在脱氮中的作用。【方法】富集培养分离筛选微生物，通过形态观察和生理生化特征及16S rDNA 鉴定细菌，定时测定其OD600研究生长曲线，正交试验研究其脱氮影响因素和最佳条件，与污水处理厂活性污泥共同作用检验其脱氮活性。【结果】分离到一株异养硝化－ 反硝化细菌，鉴定结果表明是一株不动杆菌，命名为Acinetobacter sp．YF14，这是已知报道的第一株进行异养硝化和好氧反硝化的不动杆菌。该菌在12 h 时进入对数期，22 h 时进入稳定期，45 h 以后进入衰亡期。该菌能进行异养硝化，3 d 后氨氮和总氮的去除率可以达到92% 和91% ，且无硝酸盐氮和亚硝酸盐氮积累。好氧条件下该菌能进行反硝化，在硝酸盐和亚硝盐培养基中均能将氮几乎完全去除。对该菌脱氮的影响程度大小依次为转速＞接种量＞碳源＞碳氮比＞pH。当转速为160r/min，碳源取葡萄糖，接种量1% ，碳氮比为8:1，pH 为6.5时，脱氮效果最好。该菌株可以提高活性污泥对于生活污水总氮脱除率约30%。【结论】菌YF14 可以明显加强活性污泥脱氮效果，显示了良好的应用前景。

Abstract:

Abstract:［Objective］We separated，screened and identified a heterotrophic nitrifying and aerobic denitrifying bacterium from the surface sediment of a culture pool． Furthermore，we studied the role it plays in denitrification．［Methods］We separated the bacterium through enrichment culture，identified it by observing its morphological characteristics，studying its physiological and biochemical properties and making phylogenetic analysis of its 16S rDNA sequences． Then we studied the growth curve by regularly measuring the OD600 value，studied the influencing factors and optimum conditions of denitrification through orthogonal experiment，and examined its denitrification activity through interaction with the activated sludge of sewage treatment plant． ［Results］The strain was identified as Acinetobacter and named A．sp．YF14，which is the first known Acinetobacter that carries out heterotrophic nitrification and aerobic denitrification． It reached the logarithmic growth phase after 12 hours，the stationary phase after 22 hours，and the decline phase after 45 hours． Using strain YF14 in a reactor under heterotrophic conditions，the NH +4 -N and total nitrogen removal rates reached 92% and 91% respectively within 3 days． In addition，nitrate and nitrite nitrogen were not observed during the incubation． Under aerobic incubation conditions，almost all of the nitrogen was removed through denitrification in the nitrate or nitrite culture medium inoculated with strain YF14. The orthogonal experiment results indicated that the denitrification effect was optimal when the rotate speed，carbon source，inoculation percentages，carbon nitrogen ratio and pH were 160 r /min，glucose，1% ，8:1 and 6.5，respectively． Sorting Order of the factors on the denitrification effect was rotate speed ＞ inoculation percentages ＞ carbon source ＞ carbon nitrogen ratio ＞ pH． The strain YF14 could improve the denitrification rate by about 30% when interacting with active sludge．［Conclusion］The strain YF14 coupling of heterotrophic nitrification and aerobic denitrification is feasible and is of practical value in water treatment．