Glycerol is considered an important renewable feedstock as well as an undesirable side-product of biodiesel production. The aim of this study was to determine whether supplementing a culture medium with a combination of three different carbon sources (olive oil, glucose and glycerol) would optimize lipase production by the yeast Yarrowia lipolytica. The optimization experiments were conducted with a statistical approach using the mixture design. Analysis of the response surface revealed that it would be possible to compose a medium in which both an an extracellular lipase activity of 0.1 U/mL and up to 37.5 g/L of pure glycerol could be obtained. An YPO-Gl30 medium consisting of 30 g/L glycerol and 19.2 mL/L olive oil was selected for further investigation. Although a high biomass yield was found in all cultures, the glycerol content of the YPO-Gl30 medium slightly influenced yeast growth, but it did not prolong the duration of the lag phase. The hydrolytic activity of the extracellular lipases produced in YPO-Gl30 medium was satisfactory.
Keywords: Glycerol; Lipase; Lipolytic activity; Mixture design; Yarrowia lipolytica.