The use of Yarrowia lipolytica to reduce pollution in olive mill wastewaters

Wastewater produced from the processing of olive oil presents a serious pollution problem in the Mediterranean area, because of its high chemical oxygen demand (COD) level (100–200 g/litre), and the high level of other organic and inorganic compounds. This paper examines the growth of the yeast Yarrowia lipolytica ATCC 20255 on olive mill wastewater. The practical results presented show that the yeast is capable of reducing the COD level by 80% in 24 h, when grown in a 3.5 litre fermenter. This produces a useful biomass of 22.45 g/litre and the enzyme lipase. During this process, most of the organic and inorganic substances are consumed.