Polaromonas sp. strain xmsr204 producing a mucoid exopolysaccharide and use thereof

Abstract

This invention discloses a *Pneumocystis nigra* strain XMRS204 producing sticky extracellular polysaccharides and its applications. This strain was isolated from the intestine of a deep-sea amphipod in the Mariana Trench and forms milky-white, highly sticky colonies on LB agar. After fermentation, the strain yielded extracellular polymers through centrifugation, ethanol precipitation, dialysis, and freeze-drying; the main component of these polymers was acidic polysaccharides. The infrared spectrum of the polysaccharides purified by agarose gel size exclusion showed the presence of O–H, C–H, and –COO groups. ‑ It contains typical polysaccharide functional groups such as C–O–C glycosidic bonds. In a 2% aqueous solution, this polysaccharide has a viscosity of 1473 mPa·s, approximately three times that of hyaluronic acid (molecular weight 300 kDa) and significantly higher than polyglutamic acid (molecular weight 700,000–1,100,000). The strain and its polysaccharide provided by this invention can be used as biomaterials and thickeners in the food, pharmaceutical, and cosmetic fields.

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