Diversity And Biological Activity Of Cultured Bacteria In Weizhou Island,Beihai

The ocean occupies about 70%of the Earth’s area which contains rich and diverse microbial resources.China is a big marine country,and the marine area accounts for 32.87%of the total land area.Guangxi Beibu Gulf is a natural semi-enclosed shallow bay in the northwest continental shelf of South China Sea,with warm climate,sufficient heat and abundant precipitation all the year round.Weizhou Island,located in the middle of the Beibu Gulf,is the youngest volcanic island in China.The oceanic climate is remarkable,and its special marine environment has created a special community composition.Therefore,the mining of marine bacterial resources in Weizhou Island in Beihai is conducive to the discovery of diverse and complex microbial composition,and plays an important role in the study of species diversity,genetic metabolism,and other aspects.This study focused on the study of bacterial resources of tidal samples and marine sediment samples from Weizhou Island,Beihai.11conventional media and 2 innovative media were used to analyze the culturable bacteria in the samples.Among them,HY1 innovative medium(Trehalose-malt extract powder medium)was suitable for isolating of Actinomyces,as well as a small amount of Firmicutes and Proteobacteria.HY2 innovative medium(Mangrove leaf rot medium)was more suitable for the separation of Firmicutes and Proteobacteria.A total of 279different species of bacteria were isolated from different samples by using a variety of conventional media and 2 innovative media,which were distributed in 5 phyla,10 classes,31 orders,44 families,95 genera,including 18 potential new species.From the gene level,7 kinds of functional genes were screened for the purpose of screening functional bacteria with antibiotic biosynthesis gene clusters or other bioactive products clusters.The results showed that there were 10 strains with more than 6 kinds of functional genes,8 strains with more than 5 kinds of functional genes,55 strains with more than 4 kinds,30 strains with more than 3 kinds,and 133 strains with at least one functional gene.Based on the experimental conditions,the biological activity(including enzyme-producing activity and antibacterial activity)of 220 strains were detected by a variety of enzyme production function detection media and the plate confrontation method.A total of 130 strains with biological enzyme activities such as protease,phytase and cellulase as well as the function of degrading potassium and inorganic phosphorus were preliminarily screened.At the same time,120 strains were preliminarily screened out with antibacterial activity.Based on 16S rDNA gene sequence and genomic data,physiological and biochemical characteristics,and cytochemical characteristics,2potentially new taxa with biological activity were identified by polyphase classification,including strain GXH0341~Twhich isolated from decayed pine soil and strain GXH0434~T which isolated from the seaphore of Weizhou Island,namely,Bacillus pinisoli and Microbulbifer litoralis.