Improvements in lipase production and recovery from Acinetobacter radioresistens in presence of polypropylene powders filled with carbon sources

Polypropylene powders as the adsorbent for organic solution containing n-hexadecane and olive oil were employed as the carbon source for producing an alkaline lipase from Acinetobacter radioresistens. The best volumetric ratio of n-hexadecane to olive oil around 5 for lipase production was determined from shake-flask and fermentation cultivations. The existence of a maximum time course lipase activity of the aqueous phase was attributed to the compensation effects of olive oil on cell growth and lipase production, repression of lipase synthesis by oleic acid, and lipase adsorption on the supports. A linear relationship between the average cell growth rate in the exponential phase and the ratio of surface areas of the supports was found. The benefits of using the present fermentation process include less foaming and emulsion of the broth, less organic phase used, higher lipase production, and easy recovery of the lipase in the centrifugation step.