Isolation and characteriation of extreme halophiles Halomonas aquamarina and Halomonas marina from trigger fish, Abalistes stellaris (Bloch & Schneider, 1801)

Abstract

Screening of bacteria from the skin, gills and gut of the marine triggerfish, Abalistes stellaris (Bloch & Schneider, 1801), collected from Vizhinjam, Kerala, India, led to the isolation of 8 halophilic bacterial strains. The isolates were able to grow optimally in culture media with 5-15% salt content. Of these, 3 extremely halophilic bacterial isolates that grew in 20-25% of salt were selected for genotypic characterisation. Bacterial strain, IJ1, isolated from skin, and strains, IJ5 and IJ6, isolated from gut of A. stellaris grew optimally at pH 7.0 and 5-15% NaCl at 35 °C. The cells were Gram negative short rods. According to the phenotypic characteristics and comparative partial 16SrRNA sequence analysis, the strain IJ1 was identified as Halomonas marina strain DSM 4741 (GenBank Accession Number: KC599209) and strains IJ5 and IJ6 as Halomonas aquamarina (GenBank Accession Numbers: KC620376 and KC599210 respectively). H. aquamarina has been reported for the first time from any environment in India and both the strains have been deposited in the microbial repository of National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, India.