Abstract
A primary and secondary screening of several wild types of microorganisms, living in spoiled food and oily waste products, as potential lipase producers has been performed. The endemic wild type encoded as M2, isolated from spoiled milk, showed noticeable lipolytic activity and was identified as the yeast mould Geotrichum candidum penicillatum strain. The oil refining waste was used as a sole carbon source in the media for lipase production by the isolated microbial strain in concentrations of (mL/L): 10, 30, 50 and 70. Its utilisation in concentration of 50 mL/L resulted in highest lipolytic activity of 0.8 U/mL and a biomass production of 34.72 g/L. When the medium with 10 mL/L oil waste was used the maximal lipolytic activity was 0.44 U/mL and the maximal growth had a value of 13.16 g/L. Since the downstream processes were very complicated when using the sunflower oil waste in high concentrations, the medium with only 10 mL/L was used for further evaluation of the process parameters. The effects of cultivating conditions such as: inoculum concentration, mixing rate, initial pH of the medium e.t.c. on the biosynthetic activity of the selected strain, were all examined. It was clearly shown that the neutral pH area, the high agitation rates and the high inoculum concentrations had a very negative effect on both the biosynthetic activity and the growth of the fungus.
