Bacteriocin production by indigenous marine catfish associated Vibrio spp.

Fifty strains of genus Vibrio were isolated (identified) from healthy and diseased marine catfish(es). The isolates were screened for bacteriocin (vibriocin) production. About 32% isolates were found bacteriocin producers. The best producer was identified as Vibrio anguillarum AVP10. The maximum production of vibriocin AVP10 was manifested at 29 degrees C at pH 7, after 18-20 h of incubation. Vibriocin activity was enhanced in the presence of citrate-phosphate buffer. The vibriocin AVP10 withstands autoclaving temperature and showed activity even after prolonged chloroform treatment. Proteolytic enzymes inhibited its activity, while lipolytic enzyme had no effect. It was found bioactive only against intrageneric bacterial strains. Mode of action of vibriocin AVP10 varies with the indicator (sensitive) culture used i.e. bactericidal effects was exerted against V. anguillarum AVS9 while bacteriostatic effect was shown against entero-toxigenic E. coli.