Biosynthesis of silver nanoparticles using Lactobacillus delbrueckii subsp. bulgaricus cultured for anti-fungal activity against Pyricularia oryzae

The rice is the main food crop worldwide. The fungi Pyriculariaoryzae infected the rice and caused a decrease in rice production. The silver nanoparticle (AgNPs) are popular in several research areas such as cosmetics, agriculture, and medicine due to their biological activities and environmentally friendly. Interestingly, the biosynthesis using the microbe is a preferred alternative route for AgNPs production because it does not involve a supplementary reducing agent. The objective of this work was to biosynthesize the AgNPs using Lactobacillus delbrueckii subsp. bulgaricus and then also evaluate for antifungal activity against P.oryzae. Biosynthesis of AgNPs was used Lactobacillus delbrueckii subsp. bulgaricus cultured with AgNO3 in Man, Rogosa, and Sharpe medium. AgNPs characterized using UV-Vis spectrophotometer and particle size analyzer (PSA). The AgNPs sample at different concentrations (0.1%, 0.25%, 0.5%, 10%, 25%, 50%, 75%, and 100%) were evaluated for antifungal properties against P. oryzae using the agar diffusion method. Results confirmed the absorbance maximum of AgNPs at 423 nm. The size of the AgNPs was 2.0 nm. AgNPs showed antifungal activity against P. oryzae and the highest activity was observed at 0.75% concentration.The results showed the AgNPs could be used as a complementary to bio-fungicide against P. oryzae in the blast disease treatment of rice.