Metal-squid-chitosan nanoparticles as antifungal agents against neurospora spp. pathogen on pleurotus sajor-caju: in vitro and in vivo studies

Abstract

Contamination of oyster mushroom (Pleurotus sajor-caju) cultivation with orange mold (Neurospora spp.) poses a significant economic threat, underscoring the need for sustainable, eco-friendly antifungal strategies. To address this, this study evaluates the efficacy of chitosan nanoparticles (CNs), chitosan–copper (CN–Cu), and chitosan–silver (CN–Ag) nanoparticles. These were synthesized from squid-pen-derived chitosan using ionic gelation. Furthermore, characterization showed that nanoparticles containing high-deacetylated chitosan (DD > 90%) and low molecular weight (150 kDa) offered the best stability and activity. In vitro assays revealed that CN–Ag was the most potent, inhibiting N. crassa mycelial growth and biomass by almost 100% at 150 ppm. In addition, in in vivo tests on infected substrate bags, CN–Ag effectively suppressed mold growth. Interestingly, while treated bags initially yielded lower yields than uninfected controls, by the third week, the mushroom mass in the CN–Ag group surpassed that of the controls. Overall, these results highlight high-DD CN–Ag as an effective, sustainable solution for fungal contamination and suggest it may enhance productivity in commercial mushroom systems.