Lipid and gamma-linolenic acid production by two oleaginous fungi from potato processing wastewater

This study examined the utilization of potato processing wastewater as the feedstock by two oleaginous fungi, Aspergillus flavus I16-3 and Mucor rouxii, for lipid and gamma linolenic acid production. The high strength wastewater contained soluble carbohydrates of 36.2 g/l, soluble chemical oxygen demand (COD) of 40 g/l, total soluble nitrogen of 0.62 g/l, and soluble total phosphorus of 0.24 g/l. Its total carbohydrates and total soluble nitrogen ratio was 72.4. Without addition of any external nutrients, 3.3 g/l and 4.1 g/l of lipids were produced by Aspergillus flavus I16-3 and Mucor rouxii, respectively, with corresponding maximum GLA yields of 132 mg/l and 180 mg/l. Aspergillus flavus I16-3 and Mucor rouxii reduced COD from the wastewater by 60% and 90%, total soluble nitrogen by 100% and 98%, and total soluble phosphorus by 92% and 81%, respectively. Thus the oleaginous fungi can produce lipids and GLA from the potato processing wastewater as well as efficiently remove COD and nutrients.