Isolation of exopolysaccharide, galactan from marine Vibrio sp. BPM 19 to template the synthesis of antimicrobial platinum nanocomposite

Herein, a galactan exopolysaccharide (EPS) producing marine bacteria Vibrio Sp. BPM19 was reported. Phylo-genetic analysis based on 16S rRNA gene sequencing showed the proximity of the isolate to Vibrio alginolyticus strain 1306. Gel permeation chromatography revealed the molecular weight of the purified EPS was about 6342.3 Daltons. 1H NMR, 13C NMR, and FTIR analysis indicated that isolated EPS comprises high molecular weight polysaccharides. HPLC analysis suggests that the EPS is composed of a repeating unit of galactose. DSC-TGA studies support that the EPS has very high thermal stability. The potential application of purified EPS in nanotechnology was demonstrated by the synthesis of platinum nanocomposite (PtNC). The PtNC was charac-terized by energy-dispersive X-ray diffraction, transmission electron microscopy, zeta potential, particle size analysis, and FTIR. The antimicrobial potential of the PtNC was demonstrated against drug-resistance Salmo-nellae typhi and Staphylococcus aureus. The result suggested the possible commercial scope of the isolated strain to produce galactan, which can synthesize antimicrobial metal nanocomposite.