Statistical Optimization by Response Surface Methodology to Enhance Lipase Production by Aspergillus fumigatus

Lipases have various commercial applications and microorganisms serve as a potential source of production.

The aim of this paper was to study the effect of interactions among different production parameters on lipase yield of Aspergillus fumigatus.

Plackett Burman and Central Composite Design (CCD) were established by using Design Expert software 10.0.

In the present study, interactions were studied for six different variables such as inoculum size, pH, temperature, galactose concentration, peptone concentration and incubation time. In Plackett-Burman design, galactose concentration, peptone concentration, pH and incubation time were found to be important factors. Using the statistical approach, the optimum factors were found to be as: galactose concentration (1.5%), peptone concentration (1.8%), pH (10.0) and incubation time (72 h) at 45°C under response surface curves. Upon statistical analysis, the coefficient of determination (R²) obtained was 0.9318 which showed that the model was significant.

The statistical tools used predicted the optimal conditions for the production of the lipase. The optimized parameters were galactose concentration 1.5%, peptone concentration 1.4%, temperature 45°C, pH 10.0 and incubation time of 72 h for obtaining a maximum lipase activity of 6.22 U/ml.