Cultivated Marine Bacterial Diversities Marine Sediments In The North Of The South China Sea And Taxonomic Analysis Of One Novel Marine Bacterium

Complicated and unique marine ecosystem provides an important support for the species diversity of marine microorganism. Different microorganisms have different metabolites, which becoming a new resources to develop new natural food preservatives and anti-cancer drugs. The research of this paper mainly include:Cultivated marine bacterial diversities have been studied in two specific ecological environments in Guangxi inshore sediments and the South China Sea deep-sea sediments, and taxonomic positions of one novel bacterium has been analysised. The results are as follows:1. A total of222strains were obtained from marine sediments by conventional cultivation-based method. According to16S rRNA gene sequences alignment, strains isolated from Guangxi inshore sediments belong to4phylum and40species. Marine bacteria isolated from the South China Sea deep-sea sediments in different temperature. At28℃,75strains were isolated, which belong to3phylum and27species. At10℃,33strains were isolated, which belong to3phylum and19species. Bacillus is the advantage species in all.2. Taxonomic analysis of a novel marine bacterium strain:QZ-16was isolated from Maowei Sea of Qinzhou. Highest sequence similarities were to Formosa spongicola A2(95.5%) and Formosa undariae WS-MY3T (95.0%), Similarity is lower than97%. In NJ and ML system evolutionary tree, QZ-16and Mesoflavibacter zeaxanthinifaciens were at the same branch. On the basis of phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain QZ-16was considered to represent a new genus and species in the gene Mesoflavibacter, which name as Mesoflavibacter maoweihai3. Antibacterial activity of those bacteria were tested through filter paper method. Guangxi inshore sediments and the South China Sea deep-sea sediments (28℃and10℃, which strain metabolites have inhibitory effect on four kinds of indicator bacteria accounted for72.5%,37.0%and89.5%of the total respectively. Toxicology activity were tested through brine shrimp lethality assay. Marine bacteria from Guangxi inshore sediments and, Brine shrimp lethality assay results showed that18strains have high brine shrimp lethality activity, in which11strains isolated from Guangxi inshore sediments, which accounts61.1%of all, another7strains isolated from the South China Sea deep-sea sediments (28℃:4;10℃:3). However, there were16strains combined both antibacterial activity and toxicology activity.