Production of novel bacterial exopolysaccharides by using Phyllobacterium sp.nov.921F bacterial strain

Abstract

The invention relates to a bacterium capable of producing bacterial exopolysaccharide, and provides a method for producing the bacterial exopolysaccharide by using the strain. The strain has the characteristics of simple nutritional requirement, easy culture, and high yield of the exopolysaccharide. In particular, a semisynthetic medium in the invention is used for to ferment the strain to obtain higher sugar yield. The strain is cultured in a gravy liquid medium containing 3 percent of sucrose for 72 hours, and the yield of a strain exopolysaccharide reaches 1.5 grams per 100 millimeters. The bacterial exopolysaccharide is white powder and is soluble in water, and the weight-average molecular weight thereof is 736 kD, wherein the apparent viscosity of 1.0 percent sugar solution at room temperature is 655 mps. A study on the property of the bacterial exopolysaccharide shows that the polysaccharide consists of glucose, galactose, and repetitive units formed by pyruvic acid substituents, and the mol ratio of the three components is 1 to 1 to 1. The polysaccharide is different from that produced from any industrial production strains in the past; at the same time, as the strain for producing the bacterial exopolysaccharide, the strain of the invention has the characteristics of high product yield, good stability, short production cycle and low cost, and can realize industrial application and production.

Description

technical field [0001] Biotechnology Background technique [0002] The currently reported strains capable of producing exopolysaccharides are the following: D-glucose, D-galactose, D-mannose, L-rhamnose and D- Acidic polysaccharide composed of glucuronic acid, exopolysaccharide composed of glucose and xylose produced by Chlamydomonas ulvaensis, and polysaccharide composed of D-mannose and arabinose of M.tuberculosis. Streptococci S. equi and S. zooepidernicus are able to produce hyaluronic acid consisting of glucuronic acid and glucosamine. Streptococcus thermophilus (S. Thermophilus) is capable of producing polysaccharides consisting of repeating units of D-galactose, D-glucose and N-acetylgalactose. Wild Xanthomonas Campestris can produce xanthan gum, which is composed of D-glucose, D-mannose, and D-glucuronic acid. There are also a few species that can produce homogeneous glycans, such as extracellular glucans produced by Leuconostoc sp. and Pediococcus sp.; extracellu...

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Problems solved by technology

[0003] Phyllobacterium sp.nov.921F is capable of producing exopolysaccharides. According to the inventor's information and literature search, there is currently no research report on the exopolysaccharides produced by Phyllobacterium

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