Isolation, Purifying Of Lithoautotrophic Nitrifying Bacteria

Nitrifying bacteria is used in aquaculture, wastewater nitrogen removal and eutrophication lakes restorations have good application prospects. At present, the nitrifying bacteria agents have been applied to aquaculture, but the types of such products are less and many of them has poor application performances, high prices and so on, it is urgent need to develop and apply some better and cheaper nitrifying bacteria agents. In the areas of the wasterwater nitrogen removal and eutrophication lakes restoration, nitrifying bacteria agents are still has not practical application.This research from sewage treatment plant activated sludges, lake sediments, soil etc. niches separate two compounder which contain ammonia-oxidizing bacteria named AT6, AT7, one compounder which contain nitrate -oxidizing bacteria named y3-2, but the three compounders couldn't purified. Through 16SrRNA sequence analysis and the morphology of bacteria identified by electron microscopy, AT6, AT7 were identified belong to the genus Nitrosomonas of ammonia -oxidizing bacteria, y3-2 was belong to the genus Nitrobacter of nitrite-oxidizing bacteria. AT6 and AT7 were not difference in nitrification capacity, so chose AT7 and y3-2 to do the follow-up study.They were investigated the stability in continuous transfer culture and the tolerance to glucose and peptone, the results were that AT7 and y3-2 had good stability in continuous transfer culture and they had better tolerance to glucose and peptone than purified nitrifying bacteria, they had a certain possibility in application.Subsequently, put AT7 and y3-2 into the simulated aquaculture water and eutrophic lake water at the bacteria concentration 1.0×10⁵cfu/mL in glass tanks in the laboratory ,the results showed that: y3-2 in the two kinds of water bodies had both good ability to remove nitrite, in simulated aquaculture water containing 10mg/L of NO₂-N , NO₂-N removal rate was 78.8 percent after 8 days use the bacteria, in the eutrophic lake water, the nitrite concentration was 0.48mg/L in the water use bacteria , the nitrite concentration was 0.89mg/L in control; AT7 in the two kinds of water bodies hadn't good performances, the reason may be that AT7 was not suitable in low concentration ammonia.