一株耐盐异养硝化−好氧反硝化菌Rhodococcus sp.LS-2的分离鉴定与脱氮性能研究

Isolation,Identification and Nitrogen Removal Performance of a Halotolerant Heterotrophic Nitrification-aerobic Denitrification Bacteria Rhodococcus sp.LS-2

高盐含氮废水通常采用生物法处理,但高盐带来的盐胁迫会影响淡水菌的脱氮性能,导致普通反硝化微生物难以有效脱氮。海洋微生物对盐浓度具有较高的耐受能力,可以用于高盐废水脱氮。本研究从深海底泥中富集筛选出一株耐盐的异养硝化−好氧反硝化细菌LS-2,利用生理生化实验及16S rRNA扩增子测序技术对其进行分类鉴定,并基于单因素实验探究不同环境因素对菌株生长及脱氮性能的影响。结果表明:经鉴定菌株LS-2为革兰氏阳性菌,隶属于红球菌属(Rhodococcus),其对盐的最大耐受浓度可高达6%。该菌株的最佳培养条件为:盐浓度为4%、C/N=15、初始氨氮浓度为120 mg/L、pH 7、30℃、140 r/min。在此条件下,菌株对氨氮的去除率为95.5%,且没有硝态氮与亚硝态氮的积累。该菌株具有良好的耐盐能力以及脱氮性能,在高盐含氮废水处理领域具有潜在的应用价值。

High concentration of nitrogen in saline wastewater is usually treated by biological method.However,the high salinity stress can inhibit the nitrogen removal performance of freshwater bacteria.In contrast,marine microorganisms exhibit a higher tolerance to salinity and can effectively remove nitrogen in the saline wastewater.In this study,a novel strain LS-2 was isolated from the marine sediment.The bacterium was identified as Rhodococcus sp.by 16S rRNA gene sequencing and physiological tests.Moreover,the maximum tolerated salt concentration of bacterium and the effects of different environmental factors on the nitrogen removal were investigated by series of single factor experiment.The results show that the salt tolerance of this strain is 6%,and the optimal conditions for nitrogen removal include salinity of 4%,C/N ratio of 15,initial ammonia nitrogen concentration of 120 mg/L,pH 7,30°C and 140 r/min.The removal efficiency of ammonia nitrogen is up to 95.5%without the accumulation of nitrite and nitrate nitrogen in the process.This study demonstrates that Rhodococcus sp.LS-2 displays excellent nitrogen removal performance,highlighting the potential application of this bacterial consortium in nitrogen elimination for the sanity wastewater.