The Study On Fermentation Conditions And Enzyme Production Capacity Of Antagonistic Bacteria BHG、BTZ

Grape Botrytis cinerea, which lead to great loss of grape production, is one of the significant grape diseases in the world. Nowadays, agronomic control and chemical control are important prevention and control measures; however both of them have some limitations. The antagonistic bacteria BHG and BTZ, which are extracted from the microflora of grape leaf in Lanzhou Honggu District Open field and in Tianzhu Sunlight Greenhouse in Gansu province, of remarkably showed inhibition to grape Botrytis cinerea. From the perspective of bacteriostatic effects, fermentation conditions, fungistatic protein activity and characteristics, physiological and biochemical test of BHG and BTZ, the paper drew a conclusion as follows:1Bacteriostatic action of BTZ and BHGTaken the Botrytis cinerea as indicator bacteria, the action mechanism and bacteriostatic action of BHG and BTZ is tested through the experiment, which demonstrated that the bacteriostatic belt wide of BHG and BTZ is respectively7.00mm and10.00mm, while the inhibitive rate is71%and70.05%after the5days cultivation on the plate. Due to these two strains, the mycelium of Botrytis cinerea is resulted in intracellular vesicles phenomenon which is showed as deformity, shorter and cruder. The inhibition rate of BHG and BTZ fermentation liquid is98%and98.8%for pathogen spore Botrytis cinerea. BHG and BTZ strains have identical bacteriostatic on7ordinary kinds of pathogenic fungal growth including Thielaviopsis basicola Ferraris., particularly the inhibition rates for Marssonina coronaria Davis is prespectively61.67%and60%.2Fermentation conditions optimization and bacteriostatic action mechanism study of BHG and BTZFermentation conditions of BHG and BTZ strains were analyzed in order to improve the production amount of bacteria and bacteriostatic characteristics of two strains. The result is demonstrated as the glucose and peptone with carbon source and nitrogen source components is the best fermentation conditions for BHG, and optimum temperature and time length are28degree and36h with initial pH7.0and liquid volume20ml/150ml; while the best fermentation conditions of BTZ included Sodium carboxymethyl cellulose and Ammonium sulphate,28degree, cultivation time length36h, starting pH6.0and liquid volume20ml/150ml. Through the study of different concentration of ammonium sulfate salting-out precipitation, when the ammonium sulfate concentration is70%two strains have the highest inhibition effect on Botrytis cinerea which is respectively70%and78.94%. The inhibition effect of BHG and BTZ is rather stable under the high temperature, and the antimicrobial activity is still active is different temperature after20mins treatment. From pH4to pHll circumstances the protein has certain sterilization ability. While the bacteriostatic of strain is weak under acidic environment comparing to alkaline environment and the bacteriostatic is the best under the neutral environment.3Identification of antagonistic bacterium BHG and BTZ strainsThrough more than20physiological and biochemical test of the BHG and BTZ strains, BHG is identified Preliminary as Pseudomonas.pseudomallei and BTZ is identified as Pseudomonas mallei.4Preliminary study on the enzyme activity of antagonistic bacterium BHG and BTZThe enzyme screening of BHG and BTZ strains showed the two strains were able to secrete amylase, lipase and cellulose. Strain BTZ is superior to producing amylase and lipase, and the enzyme activity was higher, while the strain BHG is better in producing cellulose.