Isolation And Identification Of Marine Photosynthetic Bacteria And Their Application In The Ornamental Fish

There are all kinds of biology resources in marine world, especially microorganisms, which are great valuable. So in recent years, exploitment and application about the microbial resources from the sea water are more and more popular. Photosynthetic bacterium (PSB) is a sort of microorganisms that can use light as energy source and perform photosynthesis which can not release oxygen. Since photosynthetic bacteria have a series of especial physiological characteriscs, they are more and more accounted of their application. Now they are wildly used in the field of food, agriculture, aquiculture, sewage farm, and so on.In this study, molecular methods based upon 16S rDNA and ARDRA (amplified ribosomal DNA restriction analysis) were used to investigate facultatively anoxygenic phototrophic communities in sediment samples, which were collected from a coastal region of Luoyuan Bay in Fujian province during a research of microbial diversity associated with the marine environment in May, 2006. Thirty five strains enriched by the photosynthetic bacteria liquid medium were isolated from the sediment samples. ARDRA is used for the analysis of diversity of the bacterial strains. 16S rDNA genes amplified from the isolated strains are digested into four and/or six bands by restriction endonucleases Rsaâ… and Hhaâ… , respectively. The digested products of Rsaâ… have nine banding types and the digested products of Hhaâ… have eleven banding types. After calculating the matrix by Popgen Soft and constructing the phylogenetic trees of 16S rDNA bands by Mega 3.1 soft, thirty five strains are placed into ten major groups.Ten representative strains are selected for subsequent 16S rDNA sequencing and phylogenetic analysis. The results show: there are abounds of photosynthetic bacteria in the sediment samples and some strains are worth while further research. The strains c3112, c115, c118, c111 and c313 belong to genera Rhodopseudomonas, Rheinheimera, Ectothiorhodospira,Rhodospirillaceae and Prosthecochloris, respectively. The strain c121 does not belong to photosynthetic bacteria, but it is a novel strain after a series of further studies. Its information has been submitted into the related international organizations and the article about it is going to be published. The strains c314, c124, c312, c117 are not photosynthetic bacteria, and they are most correlative to the genera marinobacter. More studies should be done to determine their clade of these four strains.Moreover, a photosynthetic bacteria strain c3112, identified as Rhodopseudomonas palustris, is used into the breeding of zebrafish to study the effect of PSB on the water. The results show: after appending PSB, NH4-N, NO2-N and COD in the water decrease distinctly, and the rates are 72.3%, 40.5%, 23.0%, respectively. DO increases remarkably, up to 12.2%. pH value increases slowly in the appropriate range, but it will not influence the growth of the zebrafish greatly. When putting 103-105 cell/L of the PSB in to the water, the improvement effect is much better.