High-pressure methods for extraction of lipids from Rhodosporidium toruloides

Date

2023-7-24

Author

Erdir Kolcu, Melis

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Oleaginous microorganisms are known to accumulate lipids ranging from 20 to 80%. In this study, the lipid producing yeast was Rhodosporidium toruloides DSM 4444 was grown in enzymatically hydrolyzed cheese whey was used for 8 days and obtained biomass was disrupted by high pressure homogenizer (HPH) and high hydrostatic pressure (HHP) methods. For HPH, spent fermentation medium was directly used, applying pressures between 50-200 MPa with 3-13 passes. Response surface methodology (RSM) was used to design experimental conditions. For HHP, two different procedures were followed pressurizing dried biomass slurry and direct pressurization of the fermentation medium. High-speed homogenization (HSH) was chosen as the control for comparative evaluation. The optimal conditions for HPH were determined as 125 MPa pressure and 5 passes, resulting in a lipid yield of 32.4%. In experiments conducted with the HHP method, the optimum conditions were 230 MPa pressure, 15 minutes duration, and 1 g biomass/25 mL organic solvent. For experiments conducted with direct pressurization of the fermentation medium, the optimum conditions were determined as 300 MPa pressure, 5 minutes duration, and 30°C. In repeated experiments for the HHP method, lipid yields of 20% and 27.6% were obtained for different experimental procedures. Fatty acid methyl ester analysis demonstrated that microbial oils derived from R. toruloides contained significant amounts of palmitic, stearic, oleic, and linoleic acids. Based on the results, it can be inferred that the HPH method provided more efficient outcomes for cell disruption and subsequent lipid extraction compared to the HHP method.

Subject Keywords

Yeast lipid, Rhodosporidium toruloides, High pressure homogenizer, High hydrostatic pressure, Whey

URI

https://hdl.handle.net/11511/104807

Collections

Graduate School of Natural and Applied Sciences, Thesis