Screening and identification of two Macrolactin S-producing bacteria from the sea

Abstract

Objective:To isolate and screen active marine microorganisms from the East China Sea and to identify the phenotypes of the isolated strains.Methods:Thirty strains of bacteria isolated from the East China Sea were selected randomly,and the active strains were screened out by the anti-Escherichia coli model.The active strains were subjected to physiological and biochemical characteristics,salt-aggregation test,and 16S rDNA sequence analysis.Neighbor-joining trees were constructed by comparing the results of 16S rDNA sequences with sequences described in the BLAST server of the National Center for Biotechnology Information(NCBI);the strains were subsequently identified to genus level.Results:Strains F81612 and F201721 were screened out with the optimum salinities of 10% and 7.5%,respectively.Their morphology and biochemical characteristics were similar to those of Bacillus sp..16S rDNA sequence analysis showed that sequences of F81612 had a higher similarity to those of Bacillus subtilis;F201721 was similar to Bacillus amyloliquefaciens.Conclusion:Two Macrolactin S-producing strains have been screened out by the anti-Escherichia coli model,and they are identified as moderate halophilic Bacillus sp.