Valorization of Momordica charantia seeds into phytogenically synthesized silver nanoparticles for the protection of oyster mushrooms against Trichoderma pleuroticola

Green mold caused by Trichoderma pleuroticola is the most invasive disease of oyster mushrooms, causing massive losses worldwide. Herein, we valorized food waste, the Momordica seed extract (MSE), into silver nanoparticles (AgNPs-MSE). The synthesis parameters were optimized, and the biogenic AgNPs showed a remarkable antifungal activity against T. pleuroticola. Quantitative and qualitative analyses showed that the MSE was rich in bioactive compounds. The highly stable AgNPs-MSE was synthesized under the following conditions: MSE–AgNO3 ratio, 5:95; synthesis time, 9 min; temperature, 60 °C; and pH, 8.0. The UV absorption spectra showed surface plasma resonance peak at 428 nm, confirming the presence of spherical nanoparticles. FTIR spectra ascertained the involvement of phytoconstituents in the MSE during synthesis, and X-ray diffraction analysis revealed a face-centered cubic (fcc) crystalline structure with an average particle size of 11.34 nm. HR-TEM analysis corroborated the spherical shape, with a nanoparticle size of 8.0 nm. EDX analysis revealed the presence of silver, carbon, oxygen, nitrogen, sulfur, and chlorine in the AgNPs-MSE, which was further substantiated by XPS analysis. A zeta potential of − 29.7 mV and PDI of 0.144 revealed the good stability and uniformity of the synthesized AgNPs-MSE. The optimized AgNPs-MSE exhibited a potent antifungal activity against T. pleuroticola at 300 ppm in vitro. SEM and TEM analyses of AgNPs-MSE-treated T. pleuroticola showed hyphal system breakage and leakage of cytoplasmic contents that leads to cell death. Therefore, the use of the AgNPs-MSE as a nanoparticle-based fungicide has the potential to effectively control T. pleuroticola for oyster mushroom protection.