Valorization of olive mill wastewater by the yeast Yarrowia lipolytica

Abstract

The aim of this work was to study the ability of two different strains of the yeast Yarrowia lipolytica to grow on Olive Mill Wastewater (OMW) and their potential to produce high-value products such as lipases. Factors affecting cellular growth and OMW degradation were studied, such as nitrogen supplementation, cells concentration and surfactant addition. Both strains used were able to grow in a OMW with a COD of 19 g/L and total phenols concentration of around 800 mg/L. The strain W29 presented the highest potential for extracellular lipase production from OMW. Lipase productivity was improved by the medium supplementation with ammonium sulphate up to 6 g/L, leading to 80 % of COD degradation and 70 % of total phenols reduction. The surfactant Tween 80 enhanced cell growth and COD degradation, but had no significant effect on lipase productivity. The results evidenced that the conditions that favoured lipase production differ from the conditions that improve COD removal from OMW.