A novel Aureobasidium pullulans isolate for the biological control of Penicillium commune in potato decay and its optimization for enhanced antifungal activity using the Taguchi method

Abstract Penicillium commune is a significant postharvest fungal pathogen responsible for blue mold rot in stored potatoes, resulting in substantial economic losses worldwide. In this study, we isolated and characterized a novel epiphytic strain of Aureobasidium pullulans SBAN-IAUF-1 from potato foliage and evaluated its antagonistic activity against Penicillium commune SBAN-IAUF-12. The new isolate exhibited strong inhibitory effects, reducing pathogen growth by 60% in vitro and 69.41% in vivo, outperforming values reported for most previously studied A. pullulans strains. Extracellular antifungal metabolites produced by Aureobasidium pullulans SBAN-IAUF-1 also showed substantial antifungal activity, indicating that extracellular antifungal metabolites play a key role in antagonism. To further enhance extracellular antifungal metabolites activity, we applied a Taguchi L9 orthogonal design, which identified optimal culture conditions and significantly increased the extracellular antifungal metabolites activity. The optimal conditions suggested by L9 analysis for maximizing extracellular antifungal metabolites production were 20 °C, 7 days of incubation, pH 5, and 1% (wv − 1 ) YMB concentration. This study provides the first report of a potato-derived A. pullulans isolate optimized through Taguchi methodology for controlling Penicillium commune . The strong biocontrol activity of Aureobasidium pullulans SBAN-IAUF-1 highlights its potential as an environmentally safe and effective candidate for postharvest management of blue mold disease in potatoes.