Study And Application Of A High Polysaccharide-producing Strain

Saccharides has been found widespread commercial in the field of industry and agriculture, but most of them are extracted from higher plants, algae and some kinds of mushrooms. Recently, great attentions were paid to bacterial polysaccharides because of their stable structure and function, inexpensive price and law dosage. In this paper, a strain which could produce high-yield exopolysaccharide was introduced, including its screening, ferment technics and extraction technics optimized, its chemic constituent as well as its application.This strain was screened by our laboratory, which was identified as Agrobacterium radiobacter through physiological and biochemical characteristic determining and 16S rDNA gene string appraisal. It was named GY04.Going through about two years time, a lot of experimentations were done. Some results were get along as following:1. The strain GY04 was screened by non-nitrogenous medium, re-screening medium and basal medium from soil sample obtained in Guiyang. The organism was identified as Agrobacterium radiobacter according to 16S rDNA gene string appraisal and the Critical Manual of hackneyed Bacteriology.Round entire, convex, opaque, mucoid and milk white colonies of GY04 strain appear in 3-4 days at 28℃ on basal medium, the diameter of the colonies is about 1cm. The strain GY04 is a gram-negative. The size of cell is about 1.2-1.8μm× 0.5-0.8μm, single or doubled. After cultured 3 days, observed by the method capsule coloration, transparent ring is found, which is capsule.The strain GY04 is aerobic, nosporeforming, immotile. The organism grows at temperature between 4-42℃ and at pH value 4-9. But the optimum temperature and pH value are 28℃ and around 7, respectively. Pigment production is not observed.