Stuty On Creening, Culturing And Applying Of Efficient Ammonia-oxidizing Bacteria

At present, the marine environment of China is polluted seriously, the ocean is eutrophicationand the red tide frequently occurs. Because the marine environment is so large that the direct repairis difficult to carry out.It is important for denitrification technology of urban sewage to Screen andcultrue efficient ammonia-oxidizing bacteria.In this paper, the ecological distribution of ammonia-oxidizing bacteria which is near sea areaof NingboBeilun Port and Zhoushan is preliminary studied by DGGE （denaturing gradientgel electrophoresis） technology.Experiments have taken five points in both sediment samples thedistribution of ammonia-oxidizing bacteria.Ammonia-oxidizing bacteria in the samples in smallquantities is not the dominant bacteria in the bacterial samples and each sample pointforeach season of the different nature of the oxidation of ammonia in the sampletypes of bacteria areat least two.An activity autotrophic ammonia-oxidizing bacteria was isolated from Beilun Taisu ofNingbo. It fits a wider range of salinity and named THD-1.It features in aerobic, spherical or shortrod, and cell size is about0.5⁰.8μm×0.7¹.3μm, gram-negative, and the single colonyis colorless and transparent, needle size, smooth edges.Identified by16S rDNA sequence，it isshowed that the similarity between the srain THD-1and Nitrosomonas europaea is96.3%. Westudied the activity of ammonia-oxidizing bacteria affecting factors （pH, temperature, salinity andthe adsorbate）. Experimental results show at30℃,0²5‰salinity in the ammonia oxidationactivity is the highest, when pH value is greater than or less than8.0ammonia oxida-tionefficiency were significantly affected, and the optimum pH8.0. Adding CaCO₃as adsorbateammonia-oxidizing activity of strain was significantly improved.The method was established to culture high-density Ammonia-oxidizing bacteria. Themethod was used to culture strainTHD-1, as a result the OD600nm up to0.214, and count themaximum number of viable cells up to7.5×10⁸cells/mL by MPN. Use of bio-balls made ofammonia-oxidizing bacteria to immobilized bacteria. The balls immobilized bacteria were stillhigher ammo-nia oxidation, when they had been stored45days. Balls treat river water, ammonianitrogen remo-val rate of50%.