Formulation and Characterization of Encapsulated Bacillus spp. for Enhanced Agro-Industrial Efficacy

The use of biological control agents such as Bacillus spp. has gained increasing recognition among farmers as an eco-friendly alternative for pest and disease management. However, Bacillus spp., like other microorganisms, are sensitive to environmental stressors and require specific conditions for survival and efficacy. Therefore, to ensure its effectiveness as a biological control agent in field applications, Bacillus spp. must be incorporated into a suitable formulation. Conventional liquid formulations often fail to maintain the long-term viability of bacteria in soil environments. In contrast, bioencapsulation—particularly in the form of microcapsules—has shown promise in enhancing bacterial stability and viability under field conditions. This study investigates the influence of sodium alginate concentration on the encapsulation efficiency of Bacillus sp. Microcapsules were prepared via the extrusion technique by mixing bacterial suspensions with sodium alginate solutions at concentrations of 1%, 1.5%, and 2%, and subsequently dropping the mixture into a calcium chloride solution to form gel beads. Encapsulation efficiency was evaluated by extracting the bacteria from the microcapsules, culturing them on a suitable growth medium, and quantifying viable cells. The results demonstrated encapsulation efficiencies of 1%, 0.36%, and 1.35% for sodium alginate concentrations of 1%, 1.5%, and 2%, respectively. These findings suggest that the concentration of sodium alginate significantly affects the encapsulation efficiency of Bacillus spp., with higher or optimal concentrations enhancing the protective matrix and viability of the encapsulated bacteria.