ISOLATION AND IDENTIFICATION OF AN ALKALOPHILIC FACULTATIVE AEROBIC DENITRIFICATION STRAIN MARINOBACTER SP.B3 AND ITS DENITRIFICATION PERFORMANCE
To obtain a strain with better denitrification and nitrogen removal efficiency,an alkaliphilic denitrifying bacterial strain was isolated from a seawater Spirulina culture system.Through 16S rRNA identification and BLAST homology analysis,the genus was identified as Marinobacter,and named Marinobacter sp.B3.To clarify the denitrification performance and nitrogen conversion pathway of the sea bacillus,the effects of different single factors(dissolved oxygen(DO),carbon/nitrogen ratio(C/N),pH,and temperature)on the denitrification performance and nitrogen balance were investigated in experiment.Results of single-factor experiments showed that when potassium nitrate(KNO3)was used as the only nitrogen source,the initial concentration of NO3--N was 100 mg/L,the salinity was 32,the oscillation speed was 150 r/min(the initial DO mass concentration was 5.6 mg/L),C/N=10,pH=8,and the temperature was 35 ℃,the maximum nitrogen removal effect could be obtained.In addition,the results of nitrogen balance experiments showed that under aerobic environment,20.11％of NO3--N was converted to intracellular nitrogen,5.58 mg/L NO3--N was converted to other denitrification products(NO2--N,NH4+-N and organic nitrogen),and 74.72％was converted to N2 released.Under anaerobic conditions,26.65％of NO3--N was converted to intracellular nitrogen,and 72.86％of NO3--N was converted to gaseous products for release.The final experimental results showed that under aerobic and anaerobic conditions,Marinobacter sp.B3 had a removal efficiency of 99.89％and 93.80％for NO3--N in 48 hours,respectively,and the NO3--N removal efficiency was higher under aerobic conditions,showing a good application prospect in the treatment of aquaculture tail water in seawater factory recirculating system.
denitrificationrecirculating aquaculturebiological denitrificationaquaculture tail water treatment
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