Development of chitosan‐based nanoparticles encapsulating Bacillus velezensis CMRP4490 metabolites for enhanced in vitro control of Sclerotinia sclerotiorum

Modern agriculture seeks to control pests and diseases in the field while maintaining production, reducing the use of dangerous chemical molecules, and resorting to more sustainable solutions. One of the ways to achieve these objectives is biological control. Furthermore, combined with biological control, the use of nanoencapsulation techniques of biological control agents with materials that are bioavailable and biodegradable in the environment has proven to be an alternative to reducing the use of non‐renewable materials. Therefore, the present work aimed to develop a nanoparticle system for biological control of Sclerotinia sclerotiorum. The nanoparticle system was produced using the ionotropic gelation technique using chitosan (CHI) as a polymer. The cell‐free supernatant (CFS) of the microorganism Bacillus velezensis CMRP4490 was used to produce nanoparticles, as preliminary studies show that its metabolites act in biological control. The nanoparticles produced were prepared in different concentrations of CHI and CFS and their antimicrobial activity was evaluated against the fungus S. sclerotiorum. The encapsulated samples have a concentration of 20%–80% of CFS and 0.25% and 0.8% of CHI and showed a 100% inhibitory effect against S. Sclerotiorum, and the results obtained indicate a synergistic effect between CHI and CFS.