Screening Of High Produced Active Substances Marine Microorganisms And Active Research

Marine special ecological environment (high salt, high pressure, low temperature, low nutrition and without light) makes the marine microorganisms have unique metabolic pathways and genetic background. Therefore, they can produce active substance with special function. The research of antibacterial activity substance from marine microorganisms has become one of the important contents to develop marine resources. This research mainly screening a strain with high antimicrobial activity from sea cucumber plants seawater and sea sludge in Dalian, and antibacterial material was researched systematic. The main results were as follows:(1) 506 marine bacteria strains were isolated from sea cucumber plants water and sediment in Dalian, preliminary screening by using the filter method get 96 strains with antibacterial activity,19% of the total accounted for screening. On the basis, using the Oxford cup method to screen and getting 13 obvious bacteriostatic activity strains.2 strains have stronger inhibition to Staphylococcus aureus,1 strain has stronger inhibition to the Micrococcus lysodeikticus,5 strains have stronger inhibitory effect on Vibrio parachaemolyticus,5 strains have a strong inhibitory effect on four kinds of indicator bacteria. Choose 1 strain with strong antimicrobial activity to both gram positive and negative strains (named HS-A465) for further research.(2) Morphology observation, physiological and biochemical experiments and compared its 16 s rDNA sequence in GenBank to the strain HS-A465, determined the evolutionary status in biosphere by constructing phylogenetic tree. Results show that the strain is Brevibacillus laterosporu, the accession number of 16S rDNA sequence in GenBank is KJ398346,(3) The antimicrobial crude extract isolated by hydrochloric acid precipitation and organic solvent extraction from HS-A465 fermentation supernatant. Three components were detected by TLC and bioautography from HS-A465 antimicrobial crude extract. Separation and purification each components and antimicrobial testing to each component, the result showed that 2 component have significant antimicrobial effect.(4) The physical and chemical properties of active crude produced by the strain HS-A465 were studied in details. The crude extract treatment by different temperature, pH, organic solvent and uv, using oxford cup approach to measure antibacterial activity, the results showed that:the active substances has high temperature resistant, even at 121℃ they are still retain 81% activity. The active substance has good stability between pH 2-12; Exposured at ultraviolet 48 h remains 78% antimicrobial activity, the active substance is not sensitive to common organic solvents.