Production process technique and characteristics of microcapsules of Bacillus amyloliquefaciens against sturgeon-pathogenic Aeromonas hydrophila

Abstract:

[Objective] The aim of the present study was to optimize the production process technique of microcapsules of Bacillus amyloliquefaciens against sturgeon-pathogenic Aeromonas hydrophila, and to observe their characteristics. [Methods] Based on the use of gelatin as the wall materials, the influences of gelatin concentration, inlet temperature, feeding speed and air flow on the viable cells in B. amyloliquefaciens microcapsules were assayed using single factor method, the spray drying processing parameters of its microcapsules were optimized through orthogonal experimental design, and their morphology and tolerance to artificial gastric and intestinal juices were further examined. [Results] The experimental results showed that the optimum spray drying processing parameters to prepare B. amyloliquefaciens microcapsules were gelatin concentration of 3%, inlet temperature of 155 °C, feeding speed of 8 mL/min and air flow of 700 L/h, and the most leading influence factor on the production of B. amyloliquefaciens microcapsules was the gelatin concentration, followed by feeding speed, air flow and inlet temperature. In addition, B. amyloliquefaciens microcapsules were spherical, featured dimpled surface without holes and cracks, uniformly-distributed with an average size of 9.22 μm. They were also found to have good tolerance to artificial gastric and intestinal juices, and exhibited a good inhibitory effect on the growth of sturgeon Aeromonas hydrophila. [Conclusion] The present study laid a good foundation for the industrial production of B. amyloliquefaciens microcapsules.