Partial characterization of viscous exopolymer produced by Alkalihalobacillus sp. strain SB-D (KJ372395) with emulsification and adhesive properties.

Twenty-two alkaliphilic bacteria were isolated from spent waters of an agrochemical factory, Goa, India, and screened for exopolymer (EP) production on Horikoshi I/II media. Strain SB-D produced highly viscous cell-bound and extracellular EP quantified by alcian blue adsorption assay. The 16S rRNA gene sequence of strain SB-D showed 97.34% similarity to Alkalihalobacillus lehensis strain MLBT. The strain maximally produced EP (10.3 g/L) at pH 10.3, 25 °C after 16 h growth on shaker, followed by 4 h at static condition with 4% inoculum in the presence of 3% glucose and 0.1% yeast extract. The EP precipitated using isopropanol contained carbohydrates (212 µg/mg), lipids (130 µg/mg), and proteins (86.16 µg/mg) as major components. Further, gas chromatography detected the presence of D-glucose, D-arabinose, D-mannose, D-galactose, D-xylose and D-ribose. Preliminary studies on EP characterization revealed emulsification and adhesive properties of the exopolymer.