Identification of a Moderately Halophilic Bacterium whb45 and Screening of Its Antimicrobial and Antitumor Activity

Abstract:

The aim of this study was to isolate and identify moderately halophilic bacteria from solar saltern and to investigate their potential antimicrobial and antitumor activities. Halophilic bacteria were isolated from Ludaokou Solar Saltern in Weihai of Shandong Province. The identification of the strain whb45 was determined by their morphological characteristics, physiological and biochemical tests and phylogenetic analysis based on 16S rRNA sequence comparison. The antimicrobial activity and cytotoxic activity were screened. Our results showed that the strain whb45 was belonged to moderately halophilic bacterium. Phy-logenetic analysis showed the strain whb45 had a 99% homology with Halobacillus trueperi. The crude ex-tract from whb45 showed stronger antimicrobial activities which could inhibit the growth of several bacteria and fungi. MTT analysis revealed that the strain possessed potent anticancer activity with the stronger in-hibitory effect on several human cancer cells. Our results suggested that the moderately halophilic bacterium whb45 may be developed as a potential new source for the discovery of novel bioactive substances.

Key words:Moderately halophilic bacteria, Identification, Halobacillus, Antimicrobial activity, Antitumor activity