Novel biosynthesis of MnO NPs using Mycoendophyte: Industrial bioprocessing strategies, characterization, scaling-up production, and its evaluation as anti-phytopathogenic agents

Abstract Objectives: This is the first time in literature to the biosynthesis of rod-shaped myco-synthesized MnO NPs in average diameter ~35nm using extracellular bioactive metabolites of endophytic Trichoderma virens strain EG92 as capping/reducing agents and MnCl2.4H2O as a parent component. Methods: The wheat bran medium was chosen to grow endophytic strain EG92, which produced a variety of bioactive metabolites in extracellular fraction, which increases the yield of MnO NPs to 9.53 g/l. The whole medium and fungal growth conditions that influenced biomass generation were optimized as successive statistical optimization approaches (Plackett-Burman and Box-Behnken designs). Results: The production improvements were achieved at pH 5.5, WBE (35%), and inoculum size (10%), which increased Xmax to twelve-folds (89.63 g/l); thereby, Pmax increased to eight-folds (82.93 g/l). After 162 hours, Xmax (145.63 g/l) and Pmax (99.52 g/l) on the side of µmax and YX/S were determined as 0.084 and 7.65, respectively. Via Taguchi experimental design, fungus-fabricated MnO NPs reaction was improved by adding 0.25M of MnCl2.4H2O to 100% of fungal extract (reducing/capping agents) and adjusting the reaction pH adjusted to ~5. This reaction was incubated at 60°C for 5h before adding 20% fungal extract (stabilizing agent). Also, Pmax was raised 40-fold (395.36g/l) over the BC. Conclusions: Our myco-synthesized MnO NPs exhibit faster and more precise antagonistic actions against phytopathogenic bacteria than fungi; they could be employed as an alternative and promised nano-bio-pesticide to manage a variety of different types of disease-pathogens in the future.