Effect of process parameters on lipase production by Candida cylindracea in stirred tank bioreactor using renewable palm oil mill effluent based medium

A two-level full factorial design (FFD) was employed to determine the effects of process parameters on lipase production by Candida cylindracea ATCC 14830 in palm oil mill effluent (POME)-based medium. Ten experimental runs based on three parameters (temperature, agitation and aeration) as indicated by the FFD were carried out in a stirred-tank bioreactor. On statistical analysis of the results, the optimum temperature, aeration and agitation rates were found to be 30 °C, 1.0 vvm and 400 rpm respectively, with a maximum activity of 41.46 U/ml after 36 h of fermentation. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) value of 0.999, indicating a satisfactory fit of the model with the experimental data. All the three parameters were statistically significant at p < 0.05. The validation experiment also confirmed that apart from lipase production, there was an increase in chemical oxygen demand (COD) removal throughout the fermentation period.

Temperature, agitation and aeration as process parameters have significant influence on lipase production by Candida cylindracea ATCC 14830 in POME-based medium. The maximum lipase production of 41.46 U/ml was obtained through the statistical method, full factorial design in a stirred tank reactor with a significant reduction in fermentation time. The graphical results obtained appear to be promising taking into account that it was attained using a cheaply and available raw material with significant reduction in COD.Figure optionsDownload as PowerPoint slideHighlights
► Full factorial design was used to optimize the production of Candida cylindracea lipase in POME-based medium.
► Interactions and dependence of the selected process parameters on the lipase production.
► Optimal working conditions for lipase production in 2-L bioreactor were found to be 35 °C, 1.0 vvm and 400 rpm.
► Two-fold increment as well as reduction in fermentation time was observed based on this methodology.