一株芽孢杆菌在低氮源浓度培养基中的生长与氨氮去除特性

对菌株YB3进行了16S rRNA基因序列进化分析,并分别以NH_4Cl、NaNO_2、NaNO_3、尿素和蛋白胨为单一氮源,配制了5种低氮源浓度培养基,研究YB3在与养殖水体相近营养水平条件下的生长与氨氮去除特性.结果显示,菌株YB3属于蜡样芽孢杆菌(Bacullis cereus),在5种培养基中均能够生长,菌悬液(吸光度OD600为1.0)接种量为1.0%(v/v)时,OD600由0.010增长到0.100~0.117.在NH_4Cl培养基中,YB3的氨氮去除速率为1.23 mg·L~(-1)·d~(-1),去除率为93.5%.在尿素、蛋白胨等有机氮源培养基中,YB3将首先导致氨氮的积累,累积倍数分别为51.69和3.38,之后开始去除,去除速率为1.56和0.29 mg·L~(-1)·d~(-1),去除率为93.7%和26.8%.结果也表明,提高YB3接种量至8.0%(v/v),可以使蛋白胨培养基氨氮累积倍数下降至2.02,去除速率提高至1.07 mg·L~(-1)·d~(-1),去除率最终达到98.4%.NaNO_2和NaNO_3培养基中均未检测到氨氮,而NH_4Cl、尿素和蛋白胨培养基中也未检测到NO_2~--N和NO_3~--N,表明YB3的硝化、亚硝化和反硝化作用均不强烈,去除氨氮的同时将不会造成NO_2~--N和NO_3~--N等的大量积累.本文为菌株YB3在养殖水体调控与净化中的应用研究提供了实验基础和理论支持.

Characterization of growth and ammonia removal of a Bacillus strain under low nitrogen source condition

An ammonia-removal strain YB3 was identified using phylogenetic analysis of 16S rRNA gene sequence, and the characteristics of growth of this strain together with ammonia removal under low nitrogen source condition was also studied. For this purpose, 5 culture broths whose trophic level are similar to that of aquaculture waterbody were prepared by using NH₄Cl, NaNO₂, NaNO₃, urea and peptone as unique nitrogen resource, respectively. Phylogenetic analysis displayed that YB3 is a strain affiliated to Bacullis cereus. Results also shown that YB3 slowly grew in all the 5 broths with OD₆₀₀ starting from 0.01 to 0.100~0.117 when inoculation dose of YB3 with an OD₆₀₀ of 1.0 was 1.0%(v/v). In NH₄Cl broth, the conversion rate and efficiency were 1.23 mg·L^-1·d^-1 and 93.5%, respectively. Nevertheless, in the medium supplemented with organic nitrogen source, such as urea and peptone, ammonia accumulated firstly with an accumulation rate of 51.96 and 3.38 times, respectively. And then, ammonia was removed with removal rates of 1.56 and 0.29 mg·L^-1·d^-1, and removal efficiencies of 93.7 and 26.8%, respectively. In peptone broth, however, by increasing the inoculation dose of YB3 up to 8.0%(V/V), the accumulation multiple of ammonia decreased to 2.02, with 1.07 mg·L^-1·d^-1 and 98.4% of removal rate and efficiency, respectively. There no ammonia production was detected in both NaNO₂ and NaNO₃ broths, and also no NO₂^--N and NO₃^--N were produced in NH₄Cl, urea and peptone broths, indicating that the nitrosation, nitrification and denitrification functions of strain YB3 were all weak which meant that production of NO₂^--N and NO₃^--N would not be accompanied with removing of ammonia by YB3. In conclusion, strain YB3 could degrade ammonia under incubation condition with low nitrogen source, demonstrating possibility of the usage of this strain in aquaculture water quality control and decontamination.