Waste Cooking Oil as Substrate for Single Cell Protein Production by Yeast Yarrowia lipolytica

Abstract

Cooking oils are widely used in food preparation. During cooking, harmful compounds are formed in oils, therefore utilization of used cooking oils (waste cooking oils) is limited. Single cell protein (SCP) is dietary protein, which can be produced from various protein-rich microorganisms that are capable of utilizing industrial by-products such as waste cooking oil (WCO). In this study the utilization of industrial WCO (obtained from local potato chips manufacturer) as a carbon source for single cell protein production by yeast Yarrowia lipolytica was assessed. The medium containing 27.5 g/L WCO and C/N ratio of 5–10 for batch fermentations was determined to be the optimal composition for SCP production. In this study, the highest reported Yarrowia lipolytica biomass concentration (57.37 g/L) was achieved when WCO was used as the main carbon source. Protein concentrations were relatively low (12.6 %), which also affected the final protein yield (7.23 g/L). The resulting biomass accumulated low concentrations of toxic malondialdehyde (MDA) (2.32 mg MDA/kg) compared to concentrations initially detected in the WCO itself (30.87 mg MDA/kg). To the best of the authors knowledge this is the first study to report on MDA decrease via microbial fermentations.

Keywords

• agricultural residues
• animal feed
• low-cost substrate
• malondialdehyde
• microbial protein
• tbars test
• used cooking oil