Richment And Conservation Of Nitrifying Bacteria And Research On Its' Application In Quaculture

The autotrophic nitrifying bacteria play a critical role in nitrogen cycle in nature. The detection and application of nitrifying bacteria is limited by their peculiar ecophysiology such as strict autotrophic bacteria and slow growth. But they are urgently needed in nitrogen pollution in our country. This paper focused on the key problems about application technology of nitrifying bacteria and finished some research about the techniques of enrichment, detection method and application methods in nitrogen pollution removal. The following are the results. 1.We cultured and enriched nitrifying bacteria from BEEBEI, YUBEI, TANGJQ sewage treatment plants, and using MPN-Griess and colorimetry to detect changing microbial content and ability of denitrifying .The results showed that three samples, after 5 passages, 3 months, turned yellow from black. The number of nitrifying bacteria dramatically increased, which of BEIBEI sample reached 10⁹cfu/mL; Nitrifying activity was obviously enhanced 70%, which of BEIBEI sample reached 100%; We used ss medium to detect the change of number of intestine bacteria .The results showed that the initial number of intestine bacteria of all samples over-standarded, after enrichment and culture, which decreased significantly. 2.We adopted room temperature , 4℃, continuing passage to conserve nitrifying bacteria. Under room temperature, we inspectively used direct conservation ,and after removing culture medium ,20% deposits added to PBS(KH₂PO₄ 10 mg/L, Na₂HPO₄ 5mg/L, NaCl 100g/L, sulfasulfonamide 0.03mg/L) to store nitrifying bacteria. The results indicated direct way was better. After one year, in direct conservation, the rate of denitrifying droped from 100% to 43%, after two years, 100% to 17%. In sample added PBS, the rate of denitrifying droped from 100% to 35.5% in one year, 100% to 10% after two years. Using 4℃ conservation, the rate droped from 100% to 57% in one year,and from 100% to 32.3% in two years. The best was continuing passage, the rate of which drop to 77% in one year, 50% in two and a half years later.