Abdoulrhman Amir, Ebtsam M. Morsy and Mohammed Z. Sedik( 2015). Yeasts as a Promising Tool for Microbial Oil ProductionMiddle East Journal of Agriculture Research, Volume : 04 | Issue : 02 | April-June | 2015 Pages: 223-231
Abstract: In the present study, thirty three of oleaginous yeast isolates were obtained from different location from Egyptian soil by using enrichment technique on YPD medium. These isolates were screened on its ability to accumulate lipid within cells on nitrogen limiting medium. Estimation of biomass, lipid weight and lipid content were done for all isolates. Five isolates exhibited high values of lipid content (more than 10%). One isolate was found to produce lipid content up to 14.96% and it was identified as Rhodosporidium toruloides. The optimal conditions were studied in different nitrogen limited media to produce high amount of lipids compared to Lipomyces starkeyi as a reference strain. The highest lipid content obtained when both strains were grown on pre-production medium (1) and nitrogen limited medium 2 (NLM 2) at 25 ᴼC, at 100 rpm for 5 days. Chloroform: methanol (2:1) was the suitable solvent system to extract high amount of lipids from yeast cells. Different carbon and nitrogen sources were also studied. Sucrose and glycerol were the best carbon sources to accumulate high amount of lipid content for R. toruloides and L. starkeyi, respectively. Whereas, the mixture of peptone and ammonium sulphate (1:1) and sodium nitrate were the best nitrogen sources for producing high quantity of lipids by the tested strains reached to 41.28% lipid content for R. toruloides and 32.52% by L. starkeyi. So, it can be use R. toruloides in the economic production of lipids under the tested conditions.
Keywords: (Yeasts, Microbial Oil Production)
