Screening, Identification and Fermentation Condition Optimization of Antagonistic Bacterium Q96 Against Alternaria Alternata

In order to isolate and screen antagonistic bacteria with good control effect against A. Alternata. In this study, antagonistic bacteria were screened from vermicompost with A. alternata as the target fungus through initial screening and rescreening, and then the antagonistic bacteria were identified by morphological, physiological and biochemical characteristics and 16S rDNA analysis. The biocontrol effect of antagonistic fermentation broth was studied, and the fermentation conditions were optimized by the optimum design method. The results showed that antagonistic bacteria Q96 was screened out, and the inhibitory rate of the Q96 strain against A. Alternata was more than 60% after initial screening and rescreening. It was identified as Bacillus paralicheniformis. The inhibitory rates of spores germination and mycelial growth of the Q96 strain were 73.33% and 79.68%. The control effect of crude fermentation liquid was 60.04% in vitro. The Q96 strain can be used as a strain resource for biocontrol of tobacco brown spot.