Optimizing Fermentation Conditions of Bacillus subtilis Czk1,an Endophytic Antagonistic Bacterial Strain from Rubber Tree
Bacillus subtilis Czk1 is a bacterial strain isolated from the root of the rubber tree.In dual culture test it showed strong antagonism against many plant fungal pathogens,including all of five rubber root pathogens and eight important pathogens occurring on other crops.Therefore the bacterial strain could be potentially developed as a biological control agent.In this article its optimal culture medium and conditions were studied.The optimal culture meidium was determined by one factor experimental design and orthogonal experimental design.The results indicated that the best culture medium contained 2% glucose,1% yeast extract + tryptone + NH 4 Cl(2:2:1),0.3% Na 2 HPO 4,0.1% NaH 2 PO 4 and the proportion of C/N was 2:1.One factor experimental design was used to determine the optimal culture condition.The results showed that 33 ℃,the initial pH7.5,200 r/min,24 h culture duration,5% initial inoculation amount and 100 mL VE were the best culture conditions for Czk1.This study would provide useful data for the further exploitation of Czk1 as a biocontrol agent.