【摘要】 采用稀释土壤悬液-涂布平板法从芦竹根际土壤中分离出22株具有硝酸盐还原能力的细菌,从中筛选出一株产气快、脱氮率高的反硝化细菌LZ-14.该菌株为革兰氏阴性菌,菌体短杆状,大小2.0μm×0.5μm,兼性厌氧,可运动.以乙酸钠为碳源、硝酸钾为氮源分别考察了n(C)/n(N)和pH值对菌株LZ-14生长及脱氮过程的影响.结果表明最佳n(C)/n(N)为5,在n(C)/n(N)为5,初始硝态氮质量浓度为150mg/L的情况下,36h内可将硝态氮完全去除,TN去除率可达到84.5%.最适pH值范围在7～8之间,此区间以外,菌株LZ-14难以生长及保持脱氮能力.菌株LZ-14的脱氮过程主要发生在菌体生长的第12～36h,并伴随有一定量亚硝酸盐的累积,随后24h内亚硝酸盐可被完全降解.更多还原

【Abstract】 22 nitrate reducing strains were isolated using dilute soil suspension-spread plate techniques from soil that sampled from the rhizosphere of Arundo donax L.. Denitrifying bacterium strain LZ-14 with faster gas producing and higher nitrogen removal efficiency was screened. The cells of strain LZ-14 were Gram-negative,facultative anaerobic,mobile and short rod-shaped. The effects of the C/N ratio and pH on the growth and denitrification process of strain LZ-14 were respectively investigated with acetate and nitrate as the sole carbon and nitrogen source. The results showed that the optimal C/N ratio was 5 and TN removal rate of 84.5% was achieved in 36 hours with complete removal of 150?mg/L nitrate-N. The best initial pH range for strain LZ-14 was 7 to 8,also nearly no cell growth and denitrification could be detected. It was also found that the nitrogen removal process mainly happened in the growth phase of 12～36 hours with a considerable amount of nitrite accumulation which can be completely reduced in the later 24 hours.更多还原