Bacillus Strains for Efficient Ammonium Nitrogen and Nitrite Removals on Frog Aquaculture Pond

To effectively detox the water in a frog aquaculture pond, Bacillus bacteria capable of degrading NH₄⁺-N and NO₂^--N were collected from the ponds for screening and evaluation. Strain B2 was selected from 15 isolated candidates for this study based upon its superior nitrogen removal and enzyme producing capabilities. It showed 64.56% reduction on NH₄⁺-N and 36.39% on NO₂^--N in 5 days and adequately produced functional enzymes under either aerobic or anaerobic conditions that might present in a frog pond. The physiological and biochemical characteristics and the 16S rDNA sequence of B2 confirmed it to be a strain of Bacillus subtilis. The optimum conditions for NH₄⁺-N and NO₂^--N degradation by B2 ranged from 25℃ to 35℃ at pH 6 to 8. Further study to identify and finetune the application is in order.