CHARACTERISATIONS OF NEWLY ISOLATED HALOPHILIC BACTERIUM Salinicola sp. TSLT21 FROM SPRATLY ISLAND AND ITS ABILITY TO BIOSYNTHESIZE POLYHYDROXYALKANOATE (PHA)
Abstract
Polyhydroxyalkanoate (PHA) bioplastic is a type of plastic synthesized by microorganisms in conditions of excess carbon source. There are many microorganisms that can biosynthesize PHA, including halophiles such as Bacillus, Halomonas... However, microorganisms in the Spratly islands area have not been studied. This study presents some results of isolation and evaluation of PHA biosynthetic ability of strains isolated from Spratly Island. Among 21 strains producing PHA, TSLT21 strain demonstrated the remarkable ability to synthesize PHA up to 30.9% of dry cell biomass and the salt tolerance up to 12 %. The TSLT21 strain grew optimally at 30oC, pH 7, NaCl concentration 7%. The best carbon and nitrogen sources were glucose and yeast extract 10g/l. The 16S rRNA gene sequence of strain TSLT21 is 99.93% similar to strains of the genus Salinicola, so it is named Salinicola sp. TSLT21 and registered on GenBank with access number OL757728. The strain Salinicola sp. TSLT21 which is a newly studied strain of halophilic bacteria in Spratly Island has the ability to biosynthesize PHA.