Abstract
In our search for an active biocontrol agent against Fusarium solani and F. oxysporum, the major species causing wilt, root rot and damping-off in plants affecting crops. The fungal isolate genetically identified as Aspergillus quadrilineatus MT083999 displayed high antagonistic activities against the tested root-rot fungi, and presented valuable chitinase and beta-glucanase activities of 235.484 and 508.953 U/gds, respectively. Solid state fermentation conditions were optimized by applying 20 trails of the central composite design (Three-factor-five-level) and two responses of chitinase R1 and beta-glucanase R2 activities, respectively. The optimum activities of chitinase (386.70 U/gds) and beta-glucanase (1094.70 U/gds) were obtained in trial 4 and 2 respectively, with about 1.64-fold increase in chitinase activity and 2.15-fold increase in beta-glucanase activity when compared with initial fermentation. Biosynthesis of nano-silver from A. quadrilineatus was evaluated in 10 experiments of another design of 2-factors-5-levels. The antifungal effects of each biosynthesized nano-silver against F. solani (R1) and F. oxysporum (R2) were evaluated as Inhibition Zone Diameter (IZD).The high fungicide nano-silver against both tested phytopathogens was characterized by UV-visible spectrophotometry, Transmission Electron Microscopy (TEM), Zeta Dynamic Light Scatter (DLS) and Fourier Transform Infrared Spectroscopy (FTIR). The results indicated that A. quadrilineatus MT083999 chitinolytic enzymes and nano-silver can be applied as a novel candidate in biocontrol of Fusarium wilt infecting crops worldwide.