Screening And Culture Conditions Optimization Of Bacillus Used For Aquatic Water Purification

As diets residual,microbial metabolites and carcasses of fishes accumulate upon the pond bottom,organics can be corrupted and decomposed to toxic and hazardous substances by anaerobic bacteria.The content of ammonic nitrogen,nitrite nitrogen and sulfide in water will exceed the normal standard.Therefore it will cause the negative influence on the sustainable development and aquatic products in aquaculture.Bacillus,as a species of probiotics,have potential application value in ammonia nitrogen and nitrite degradation during the metabolic processing,and can produce large amounts of protease,amylase and other beneficial factors.Regularly putting the Bacillus to improve the water quality has been widely used in aquaculture,and the utilization of probiotics to remediate the eutrophication water has been hot points.In this paper,according to the characteristics of water in Wafangdian which was suitable for sea cuciunberfs living,bacillus which could degrade ammonia nitrogen and nitrite and improved the water quality were screened from the local pond mud.The strains' capacity in using nitrite,ammonia and nitrate was tested,and the strains' physiological and biochemical characteristics and the culture conditions were identified and optimized.The results showed that the two strains of bacteria named T01 and T02 separating and purifying from the mud sample could degrade nitrite and ammonia nitrogen,but could not degrade nitrate nitrogen.And physiological and biochemical identification of T01 and T02 showed that the two bacterial strains belong to bacillus.The results of water purification experiment of T01,T02 and compound strains(V(T01):V(T02)=1:1),showect that the T01,T02 and composite strains could rapidly degrade ammonia nitrogen and nitrite nitrogen in water,and chemical oxygen demand(COD)and pH were in the suitable range for the growth of the aquatic animals.Better growth T01 were selected for cultivation,the conclusion was:when glucose 10 g/L,starch IS g/L,peptone 5.0 g/L,soybean meal 10 g/L,Potassium hydrogen phosphate 1.5 g/L,potassium dihydrogen phosphate 1.5 g/L,magnesium sulfate 1.0 g/L,calcium carbonate,1.0 g/L,inoculation amount 1%,culture temperature 30V,speed 180 r/min,100mL/250mL,Baid vilame,the number of living bacternms reaxhed thd highrst,the value was 1.63 ×109 CFU·mL-1.