Efficient conversion from cheese whey to lipid using Cryptococcus curvatus

• Hydrodynamic cavitation under alkaline is an effective way of pretreating cheese whey.
• Nutrients of cheese whey are efficiently taken up by Cryptococcus curvatus.
• Cheese whey stimulates the lipid content and growth rate of C. curvatus.
• Utilization of cheese whey can greatly reduce the biodiesel production cost.

Cheese whey, which is a byproduct of the cheese-making process, was pretreated by means of hydrodynamic cavitation (HC) under an alkaline condition and then was converted to lipid using our newly isolated oleaginous yeast Cryptococcus curvatus. The growth rate (7.2 g/L/day) and lipid content (65%) were nearly double those obtained using commercial types of sugars such as glucose, galactose, and lactose. The lipid productivity level (4.68 g/L/day) was the highest ever reported. HC-pretreated cheese whey under alkaline condition can serve as an excellent complete nutrient source and/or as a stimulant of lipid production.