Electrospun Cellulose Acetate Scaffolds with Electrosprayed Chitooligosaccharides for Bacillus subtilis Delivery and Biocontrol

The increasing demand for sustainable agriculture necessitates the development of eco-friendly alternatives to chemical pesticides. This study reports the design and characterization of biodegradable fibrous mats for the delivery of <i>Bacillus subtilis</i>, a plant-beneficial biocontrol agent, using cellulose acetate (CA) scaffolds functionalized with chitooligosaccharides (COS). Electrospun CA fibers were coated by electrospraying with COS or COS/<i>B. subtilis</i> suspensions in a single-step process to produce open, porous biohybrid scaffolds. Scanning electron microscopy confirmed uniform fiber formation and successful deposition of COS and bacterial layers, while ATR-FTIR spectroscopy verified the chemical composition of the fibrous mats. Water contact angle measurements indicated a shift from hydrophobic to highly hydrophilic surfaces, enhancing microbial adhesion and moisture-mediated activation. Mechanical testing demonstrated that thin COS coatings slightly improved tensile strength without compromising flexibility. Viability assays confirmed that encapsulated <i>B. subtilis</i> remained viable and capable of sporulation, and dual-culture assays demonstrated effective inhibition of <i>Alternaria solani</i>, <i>Fusarium avenaceum</i>, and <i>Rhizoctonia solani</i>. These results indicate that the electrospun/electrosprayed CA/COS platform provides a protective, sustainable, and effective delivery system for biocontrol agents. This approach offers a promising strategy for reducing reliance on synthetic pesticides while maintaining crop protection efficacy.