Screening Of Organic Pollutant-degrading Bacillus And Its Clean Characterization

Accumulation of organic matter is the root cause of aquaculture water body self-pollution and micro-ecological imbalance. Organic matter removal was the key to solv the problem. Now, much progress had been achieved for organic matter-degrading bacteria from aquaculture ponds. Because of many kinds of enzymes, strong adaptability to environment, function in biocontrol, Bacillus had been widely used in bioremediation of aquaculture environment which can effective absorpt inorganic pollutants and degrad organic matter.1. Screening of targeted, metabolism efficient probiotics strains has always been the hot spot of the related research. At present, a large of probiotics had been identied from the aquaculture water, and studied influence of temperature, salinity, pH, carbon source to degradation of pollutant matters. But these strains slowly growth. And influences of different environmental factors and supplementary carbon source for strains purified high organic load water rarely reported. Based on three aerobic Bacillus store in laboratory, we had obtained three bacillus subtilis(ZY1-9, ZY2-6 and ZY3-4) with better degradation ability of high-protein matters through repeatedly domesticated, screen of casein plate, starch plate, bait plate. And tested the three Bacillus subtilis of heterotrophic nitrification-aerobic denitrification(HN-AD), results show that the strains ZY2-6 had better ability of HN-AD, respectively to 100 mg/L initial concentration of ammonia nitrogen, nitrate nitrogen and nitrate nitrogen as the sole source of nitrogen in the process of growth, 20 h ammonia nitrogen removal rate reached 100%, 76 h and nitrate removal rate reached 38.35%, 72 h nitrate removal rate reached 51.50%.2. In simulating pollution aquaculture water body with prawn bait fluid, explored the different initial salinity, temperature, and pH influence on ZY2-6 purifying water body, the results showed that pH 5.5 ~ 8.5, salinity 0% ~ 3.5%, and temperature 16℃ ~ 46℃ range, ZY2-6 had better ability to degradat organic matter and inorganic nitrogen; Explored the soluble starch(SS), brown sugar(BS), sucrose(S) and bagasse powder(B) four kinds of carbon sources in 0.05%, 0.15% and 0.25% adding level influence to ZY2-6 purifying water body, the results show that additional carbon source is advantageous to the steady growth of bacteria, promote water purification, and adding brown sugar level at 0.15%, chemical oxygen demand(COD) and total nitrogen(TN) 48 h removal rate are 55.74% and 29.40% respectively; At the same time, using the orthogonal experiment to explore influence of bait residue, ammonia nitrogen accumulation, inoculation amount and duration to ZY2-6 purifying water body, the results show that aquaculture environment protein removal mainly influenced by duration, COD removal was mainly affected by probiotics inoculation quantity, TN removal was mainly affected by ammonia nitrogen accumulation, biomass was mainly affected by bait residues.3. In addition, laboratory simulation water purification and field application research to purify aquaculture water, reserchers often used inorganic nitrogen accumulation, dissolved oxygen level, microbial community structure change etc. few aspects to evaluate overall effect of probiotics to the ecological of aquaculture environment. Taken prawn breeding pond waste water and sediment, builded indoor simulated aquaculture environment, explored environment ecological effect of Bacillus subtilis ZY2-6, increasing oxygen agent, quick lime, copper sulfate, brown sugar, bagasse, zeolite powder etc seven kinds of common repaired material. While detecting 41 kinds of water ecological parameter of overlying water physical and chemical index, and enzyme activity and related physical and chemical index of sediment, using the single factor analysis of variance, correlation analysis, and factor analysis based on the principal component method to parsing aquaculture water body ecological characteristics and ecological effect of seven kinds of repair material. Extract a aquaculture environment ecological model contained three public ecological factors such as sediment activation factor, water eutrophication factor and aging factor with cumulative variance contribution rate of 90.188%. Compared with the control, quick lime, brown sugar, Bacillus can reduce the overall water body pollution degree; quick lime, Bacillus can inhibit the process of water pollution; bagasse, brown sugar, Bacillus can inhibit the process of sediment pollution.To sum up, we had obtained three Bacillus subtilis strains which can be used to purifying pollution aquaculture water body, explored the influences of environment factors and carbon sources on the strain ZY2-6 characteristics of degradation of pollution aquaculture water body, explored the overall ecological effect of various repair matters to aquaculture environmental ecology. At the same time, analysed the ecological characteristics of aquaculture water itself and the process mechanism of aquaculture water repaired, comparative analysised the ecological effect of various repair matters, established ecological model of aquaculture water body. Our woks provided reference for the development of high efficient degradation bacteria probiotics, for the improvement of the targeted repair aquaculture water ecological.