Encapsulation of Bacillus subtilis in Chitosan Gel Beads for Eco-Friendly Crop Protection

Chitosan gel beads represent a promising biopolymer-based delivery system for encapsulating <i>Bacillus subtilis</i>, an effective biocontrol agent in sustainable agriculture. This study investigates the influence of chitosan molecular weight on bead structure, water retention, and swelling behavior, as well as its impact on the viability and antifungal activity of encapsulated <i>B. subtilis</i>. The results demonstrate that chitosan provides a protective microenvironment, enhancing microbial viability, promoting colonization, and ensuring controlled release for prolonged plant protection. Moreover, encapsulation within chitosan gel beads preserved bacterial viability during long-term storage for up to 90 and 180 days. Additionally, the biodegradable and antimicrobial properties of chitosan contribute to pathogen suppression while supporting the plant growth-promoting activities of <i>B. subtilis</i>. The encapsulated bioagent exhibited strong antifungal activity against <i>Fusarium avenaceum</i> and <i>Rhizoctonia solani</i>, highlighting the effectiveness of this eco-friendly approach as an alternative to chemical pesticides. These findings underscore the potential of chitosan-based formulations to enhance the efficacy of bioinoculants, offering a sustainable solution for modern crop management.