Studies On The Fermentation Conditions And Antibiotic Of Bacillus Subtilis B-903 Strain

ABSTRACT: This paper studies on the Bacillus subtilis B-903 strain ,it was selected from orchard in Zhengzhou by Institute of plant protection, Henan academy of agriculture sciences. It produces antagonistic substance which is strong antagonistic to various plant pathology fungi. This study showed that the fermentation time was 72h under the condition of seed liquid age 24h, culture volume 200ml/500ml, temperature 28℃,shaking speed 126r/min). It saves energy and time.Using strain Bacillus subtilis B-903 as starting strain, 13 high-yield strains were obtained after 200μg/mL NTG treatment and 100s (850w 2450MHz) Microwave irradiation,Through fermentation experiment in shaking flasks, inhibitory effect of N₁ and W₂ were above 26mm and 24mm steadily increased respectively by 21.8% and 14.8% compared with the starting strain.Then the culture filtrates were autoclaved at 121℃ for 20min in acid solution. The liquid was collected by centrifugation for 15min at 4800r/min. After the steps of 80% ammonium sulfate precipitation, decolor (the coloring matter was got rid of by active carbon), filtrate, The purified material was exhibited position in ninhydrin color reaction. We can deduce the antitungal substance may contain polypeptide, protein, amino acid.Different extracting and purifing methods were taken, such as 80% ammonium sulfate precipitation, organic solvent extraction, silica gel column chromatography etc. We can get single point.30%, 50%, 80% methylalcohol were used inODS-C¹⁸ column chromatography,active ingrement was in 80%methyl alcohol. Through the advanced equipment-nuclear magnetic resonance spectrum, active ingrement was identified. The result shows it is polypeptide. Its struture is been studying.