Development of a kaolin-based Bacillus velezensis BF01 composite for application in biocontrol of postharvest strawberry diseases.

Background: Biological control agents are promising alternatives to conventional fungicides for managing postharvest diseases but their practical use is hindered by variable effectiveness and by application challenges. One promising yet underexplored approach involves utilizing bacteria that produce volatile organic compounds (VOCs) with antifungal properties.

Results: In this study, Bacillus velezensis BF01, a strain with significant antifungal activity, was identified and isolated. Volatile organic compounds produced by this strain inhibited the growth and conidial germination of Botrytis cinerea, Fusarium oxysporum, and Colletotrichum gloeosporioides. Gas chromatography-mass spectrometry identified 90 VOCs, with ketones, esters, nitrogen compounds, aldehydes, and alcohols as the dominant components, many of which exhibited antifungal or plant resistance-inducing properties. To enhance practical application, B. velezensis BF01 was incorporated into a kaolin-based composite, which maintained long-term viability under refrigerated conditions and inhibited fungal growth through the controlled release of volatile organic compounds. This composite significantly extended the shelf life of strawberries by reducing postharvest decay.

Conclusion: The development of a kaolin-based B. velezensis BF01 composite provides an effective and sustainable biocontrol strategy for postharvest disease management. By improving bacterial stability and facilitating the controlled release of antifungal volatile organic compounds, this approach offers a practical alternative to chemical fungicides, highlighting its potential in extending fruit shelf life and improving food safety. © 2025 Society of Chemical Industry.