Optimizing Nano-silver Formation by Fusarium oxysporum PTCC 5115 Employing Response Surface Methodology

Fusarium oxysporum was grown in medium containing malt, yeast extracts and glucose on shaker at 25±1°C and180 rpm for 96 h. The mycelia were used to convert silver nitrate solution into nano-silver. The bioconversion was optimized through response surface methodology-central composite design .The factors which affected the process were pH, temperature, agitation rate, concentration of silver nitrate, time of reaction and weight of Fusarium oxysporum mass. The R² was calculated to be 98% indicating the accuracy and ability of the polynomial model to be suitable and reasonable. Positive coefficient of the factors like concentration of silver nitrate solution (E) and weight of Fusarium oxysporum biomass (F), quadratic terms A², B², F² and interaction term BC affected linearly formation of nano-silver whereas negative coefficient of pH(A), temperature (B), rate of agitation(C), time(D) along with quadratic terms C², D², E², and interaction terms such as BF decreased the nano-silver formation.