Lıpomyces starkeyı ve rhodosporıdıum toruloıdes mayalarından mikrobiyal yağların üretimi ve yüksek hidrostatik basınç destekli özütlenmesi

Lipomyces starkeyi and Rhodosporidium toruloides are able to accumulate high lipid fractions, so called microbial oil, in their cells. Microbial oils are of high potential as dietary supplements and future energy sources. In this study, use of HHP in cell disruption of Lipomyces starkeyi DSM 70295 was investigated. The HHP process variables (pressure, time, and temp) were optimized for maximal oil yield using response surface method (RSM). The pressurized L. starkeyi yeasts were imaged by scanning electron microscopy (SEM). Apple pomace was tested as sole raw material in different conditioned forms, in which only Rhodosporidium toruloides DSM 4444 was grown. The best form of apple pomace hydrolysate medium was scaled-up to 1 L and 10 L fermentor. The extracted oil samples were analyzed for fatty acid composition. A maximal lipid yield of 45.8±2.1% was obtained at 200 MPa and moderate temperature of 40 oC, within 15 min, while the lowest yield of 15.2±0.9% was observed at 300 MPa, 40 oC, and 10 min. Scanning electron microscopy (SEM) analysis revealed that lower pressure (200 MPa) caused cell distortions, whereas higher pressure (400 MPa) resulted in surface scars and swellings. It was observed that detoxified apple pomace media gave a maximum lipid yield of 47.5±2.47% at flask scale experiments. In 1 L and 10 L fermentors, the lipid yields were measured as 40.1±5.51% and 50.9%, respectively, for detoxified apple pomace medium. The apple pomace conversion was calculated as 0.08 (g oil/ g dry apple pomace) for the detoxified medium. High palmitic (C16:0) and palmitoleic acid (C16:1) contents imply that L. starkeyi-origined oils are favorable to substitute palm oil or cocoa butter. R. toruloides-origined oils were rich in oleic (C18:1) and linoleic acids (C18:2). The results proved that HHP can be effective for microbial oil extraction. Also, apple pomace was demonstrated as suitable source for lipid production.