Study On The Application Of The Complex Microbial Purifying Agent Of Bacillus And Photosynthetic Bacteria

In recent years,because the rapid developing,and increasing density of Aquaculture,significant amount of bait and metabolites are produced,which resulting in deterioration of water quality in later stages of farming and leading to disease.Although antibiotics and disinfectants were used to deal with water quality and controlled pathogens in traditional aquaculture production.However,heavy usage of antibiotics and disinfectants increases resistance of pathogens,their effect are gradually weakened.In addition,excessive antibiotics does remain in the food production,which will cause harm to consumers’ health.Nowadays,people started realizing the serious consequence of overly used antibiotics.Therefore,the standard of antibiotic usage is higher before,and this change opened up a major opportunity for probiotics,which is to improve water quality,to become the focus of healthy farming system.At this point,most of the microecological preparations that has been put into use in aquaculture are prepared from a single strain of Yeast,Bacillus and Lactic acid bacteria.These microecological cannot fully meet the needs of aquaculture products and aquaculture ecological environment.So the focus has been shifted to compound micro-ecological preparations.This study is mainly focused on compare and present the water purification capacity of Photosynthetic bacteria and Bacillus.First we conduct the Wastewater Test by mixing Photosynthetic bacteria and Bacillus in the portion of 1:1,1:2,2:1,and put into artificial wastewater to test.The results show that when they mixed as Photosynthetic bacteria:Bacillus=2:1,it get the best result.At the same time,quality analysis showed that none of the harmful bacteria were detected in this preparations and the content of heavy metal ions was within the approved range of the national bio-feed additive.Second test is to study the effects of different salinity and pH on the compound preparation,in the compound preparation for holothurian feeding experiments.We are using gradient pH(7.0,7.5,8.0,8.5),gradient salinity(25‰,30‰,35‰).The results show that the concentration of ammonia nitrogen and sulfide was better controlled when pH=7.0.When pH=7.5,the control effect of COD on chemical oxygen demand was more obvious:when the water salinity was 35‰,the control effect of ammonia nitrogen,sulfide and chemical oxygen demand in water is the best.After using compound bacteria,the structure of bacteria has changed in the intestinal of holothurian and water,such as the increasing of beneficial bacteria,and the reduction of harmful bacteria,which making the water and intestinal of holothurian have a better balance than before.