Isolation, Identification And Products Characterization Of Strain JW-725 Producing Bioactive Substance Against Eumycetes

Strain JW-725 is a bacteria isolated from a soil sample collected in alpine meadow of Xiema mountain pass,suburb of Leiwuqi, Tibet.By the antibiogramic research,the strain JW-725 has strong activity against eumycetes especially Penicillium italicum, and has activity against Gram-positive bacteria to some extent, such as Staphylococcus aureus.By the primary taxonomic study, strain JW-725 is identified as Bacillus polymyxa. The shape of the single cell is pole, and its flegellum can be seen when inspected by light microscope.The strain is facultative anaerobe.The cells of the strain are Gram-negative.The strain has endospore and the sporangium is swelling.The shape of the spore is oval,and budding from the middle or subend of the strain.The color of the strain's clone is creamy, and its size is about 1~2mm large, the edge is irregular,and the centre is hollow and ringlike.The strain can grow under 10 and survive through 50 vaccum treatment after 24hours.The optimum temperature for the strain JW-725 is 28 and its salt-resisting is under 5%.The strain can make use of D-arabinose,D-xylose,D-mannose,D-galactose, D-lactose,D-fructose,D-maltose,D-sucrose and produce acid and gas;and can make use of D-sorbose to produce gas;but can't make use of D-rhamnose. According to the shape,physiological and biochemical characters,it is identified as B. polymyxa and named as B, polymyxa JW-725.It is studied that the activity against eumycetes of the fermentation filtrate(16h) of strain JW-725 is the strongest.The optimum nutritional sources arewheat bran and soya bean meal.The fermentation filtrate reserved under 4 still has bioactivity after 20 days or so,but its bioactivity decreases much while being treated under high temperature.The pH of fermentation filtrate has much influence upon the bioactive substance,and it remains activity at the range of 5. 0~7. 0.The strain B. polymyxa is a new bacteria strain which is able to restrain the growth of eumycetes.We have studied the properties of the bioactive substance, which is the foundation of the further research.This experiment is helpful to the study of fruit antisepsis and fresh-preservation, and to the exploitation of microbiology resource of Tibet area.