Inhibition Effect Of Bacillus Subtilis On Pathogens Of Skin Ulcer Syndrome In Cultured Apostichopus Japonicus And Application In Water Purification Effect

Apostichopus japonica belongs to Echinodermata, Holothuroidea, Aspidochirota, Stichopodidae, Apostichopus. Apostichopus japonica is well know for its rich in Chondroitin sulfate, acidic mucopolysaccharides and collagen, and effect of enhancing human's immune system.Since 1980s, rearing industry of Apostichopus japonica is booming. At the same time, a series of diseases on rearing industry have emerged and bring enormous losses on rearing industry.Reared Apostichopus japonica in China suffers from a kind of skin ulceration disease, which has caused severe economic loss in recent years. The course of this disease is often very short, usually several days. The infection involves a head shaking and viscera expelling at early time, and is followed with mouth and cloacal opening tumidity, then the body of the diseased individuals will shrink and titanic together with white or blue lesion spots on the body wall. In the later period, these small lesions grow more and bigger to large ulceration and finally causes the death of individuals. This disease is highly infectious, and can often cause all individuals reared in the same pool die in a very short time.A Bacillus strain was isolated from sea water, To identify the BS-1 strains, 30 assays of physiological and biochemical determination were done. And according to the previous studies,which established the position of the two strains in bacterial phylogeny through spore stain,Bs-1 were identified as Bacillus subtilis.Marine-derived Bacillus subtilis (Bs-1)grown in PDB medium produces a antimicrobial substance which can inhibit the growth of severa1 marine bacteria isolated from sea cucumber. 1ike C6,TB.The production characteristics of the antimicrobial substance and the antimicrobia1 activity were studied. The results showed that Bs-1 grew rapidly. The results also showed that the substance was stable to heat, pH, denature reagent and proteinase to some extent. Further use of the culture supernatant of Bs-1 to control the C6,TB population demonstrated that the best result could be obtained when 3-4 ml supernatant per liter was added to the water.In application experiment,4,7,10mL per cubic meter of the Bs-1 broth culture was inoculated into fish pond water. The result showed the application of bacillus subtilis could efficiently decompose pollutants and the organic substances in the fish pond water. The concentrations of NH₃-N,NO₂-N, COD were reduced significantly comparing with the non-inoculating control. The highest remove rate of NH₃-N,NO₂-N, COD were 94.5%, 90.3% and 68.3%,respectively. Thus,Bs-1 could probably be developed to be an efficient probiotic agent.