Surface response methodology for the optimization of lipase production under submerged fermentation by filamentous fungi

A Plackett–Burman Factorial Design of 16 experiments was conducted to assess the influence of nine factors on the production of lipases by filamentous fungi. The factors investigated were bran type (used as the main carbon source), nitrogen source, nitrogen source concentration, inducer, inducer concentration, fungal strain (Aspergillus niger or Aspergillus flavus were selected as good lipase producers via submerged fermentation), pH and agitation. The concentration of the yeast extract and soybean oil and the pH had a significant effect (p < 0.05) on lipase production and were consecutively studied through a Full Factorial Design 23, with the concentration of yeast extract and pH being significant (p < 0.05). These variables were optimized using a central composite design, obtaining maximum lipolytic activities with the use of 45 g/L of yeast extract and pH 7.15. The statistical model showed a 94.12% correlation with the experimental data.