Study On Identification Of Antagonistic Bacteria B02 And Medial Components And Cultural Condition Of Antagonistic Substances Produced By B02

Strain B02 was isolated from field of Beijing suburb,it can strongly inhibits the growth of many plant pathogen.studies on the morphology of strain B02, physiological and biochemical characteristics, showed that strain B02 belongs to Busillus subtilis.The medial components and cultural condition for antagonistic activity of strain B02 were optimized by single factor and uniform test in shake-flask. Single factor result was belowe:The optimum carbon souce was dextrin, organic nitrogen source were beef extract and tryptone, inorganic nitrogen source was potassium nitrate. inorganic hydronium was a major effective factor of B02,especially MnSO₄ and FeSO₄ ,can enlarge the inhibitive circle obviously.The fianal result conclude by uniform test was belowe:The optimum medial components was composed of 1.55% dextrin, 2% beef extract , 0.4% tryptone, 1.15% sodium chloride, 1.15% potassium nitrate, and 0.5% manganese sulfate.The optimum culture condition was at temperature 30°C with starting pH between 7 and 8, inoculum volume 5%, medium volume 50ml in 500ml flask and rotation speed 200r/min. The results showed that the optimum seed aged was 24 hours, and the fermentation time was 72 hours.The experiment showed that ,carbon,nitrogen source,inorganic hydronium,fermenttaion time,temptrtue,original pH can effect the antagonistic substance produced by B02 obviously. We confirmed the optimum medial components and cultural condition ,this is very important for future study.