Optimization Of Ferment Condition Of Antagonistic Streptomyces In Vermicompost And Application In Preventing Plant Diseases

Vermicompost was a biological degradation product of organic wastes by earthworms. Some experiments showed that vermicompost could control some plant diseases when it was added to cultivation of plant as fertilizer. When being added in soil, they could affect the population of some microbe, Two actinomyces had been derived from vermicompost by confronting pathogen on cultureplates. They had the ability of antagonistic effect on some pathogens.(1) In single-factor and poly-factor experiments, some materials had been selected, and their proportion were optimized, so two kind of culture medium were gotten, 1000ml Streptomyces globisporus culture included: Sorbitol 10g, Yeast extract powder 5g, Beef extract 5g, CaCO3 5g, MgSO4 5g, NaCl 0.5g, FeSO40.01g; 1000 ml Streptomyces syringini culture included: Glucose 30g, Dissoluble starch 30g, Peptone 5g, KNO30.4g, CaCO3 5g, MgSO40.5g, NaC10.5g, FeSO40.01g.(2) Cultivating conditions were optimized in single-factor experiments, and then conditions that were more efficient were gotten. Streptomyces globisporus: optimum temperature was 30℃, seed age was 36h, initial pH was 7.5, shaking speed was 150r/min, fermentation time was 36- 48h, inoculation volume was 10%; Streptomyces syringini: optimum temperature was 30℃, seed age was 48h, initial pH was 7.0, shaking speed was 150r/min, fermentation time was 36- 48h, inoculation volume was 15%.(3) Culture mediums were optimized once again. In culture medium of Streptomyces globisporus, some materials were substituted by corn powder and bean cake powder because of lower cost. When corn powder and bean cake powder were in the proportion of 15/5, the inhibiting ability was the most. In culture medium of Streptomyces syringini, some materials were substituted by corn powder and bean cake powder. When corn powder and bean cake powder were in the proportion of 20/10, the inhibiting ability was the most. Cultivation in 50L fermentation pot was compared with in 250 ml bottle, and some factors were researched primarily.(4) Single-factor experiments of different storage conditions had been on trial. Different storage conditions could affect their activity. Under the conditions of high temperature, UV, conservation in 4℃ refrigerator, the inhibiting ability of fermentation liquid was reduced by long time. Diluted by different multiple, the fermentation liquid of Streptomyces globisporus couldn't show inhibition if the dilution multiple was more than 130, Streptomyces syringini couldn't show inhibition if the dilution multiple was more than 100.(5) In another experiment, two Streptomyces were used to control plant diseases. The fermentation liquid was sprayed to leaves, or filled in root. The results showed that they could control some diseases to some degree.