Microencapsulation of Bacillus subtilis B99-2 and its biocontrol efficiency against Rhizoctonia solani in tomato

The objectives of this study were to develop a microencapsulation procedure of B. subtilis B99-2 using maltodextrin and gum arabic as wall materials to determine the optimum conditions of spray-drying in microencapsulation, evaluate storage stability of microcapsules, and assess their biocontrol efficiency against Rhizoctonia solani in tomato under field conditions. We microencapsulated the Bacillus thallus by spray-drying with various concentrations of the wall material. Maltodextrin was found to be an efficient wall material, especially at concentrations higher than 80%, while gum arabic did not affect the bacterial survival rate. The mean survival rate of B. subtilis was more than 90%, when spray drying was performed at 145°C, with a feed flow rate of 550mLh−1, and a spray pressure of 0.15MPa. B. subtilis microcapsule survival rate was 87.53% after 540d of storage, which was a longer shelf life than that of wettable powders. Moreover, its biocontrol efficacy reached 79.91% when a dosage of 300ghm−2 was used, the microcapsule showed higher control efficacy than Thiram wettable powder against R. solani in tomato under field conditions. All these characteristics indicated that B. subtilis microcapsules have the potential to become a successful biocontrol product. Graphical abstract
Source: Biological Control - Category: Biology Source Type: research