Optimization of lipase production by Staphylococcus warneri EX17 using the polydimethylsiloxanes artificial oxygen carriers.

In this research, the combined effects of polydimethylsiloxane (PDMS) and different conditions of oxygen volumetric mass transfer coefficient (k(L)a) on lipase production by Staphylococcus warneri EX17 were studied and optimized in bioreactor cultures. Raw glycerol from biodiesel synthesis was used as the sole carbon source. Full-factorial central composite design and the response surface methodology were employed for the experimental design and analysis of the results. The optimal polydimethylsiloxane concentration and mass coefficient transfer (k(L)a) were found to be 13.5% (v/v) and 181 h(-1), respectively. Under these conditions, the maximal cell production obtained was 10.0 g/l, and the volumetric lipase activities of approximately 490 U/l, after 6 h of cultivation. These results are in close agreement with the model predictions. Results obtained in this work reveal the positive effects of PDMS on oxygen volumetric mass transfer coefficient (k(L)a) in the Staphylococcus warneri EX17 cultivation and lipase production.