Evaluation of Lipid-producing Yeast for Biodiesel Production | ||
| Egyptian Journal of Microbiology | ||
| Article 5, Volume 49, Issue 1, December 2014, Pages 81-98 PDF (902.7 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejm.2014.243 | ||
| Abstract | ||
| A TOTAL of 76 yeast isolates were isolated from different sources included soil, organic manure, rotted fruits and different pickles based on the typical morphological character of yeast using light microscopy. These isolates were screened for their ability to accumulate intracellular lipids within the cells by culturing on nitrogen-limited medium (productive medium) and using Sudan Black B staining technique. Sixty lipid producing yeast isolates were detected. Estimation of biomass, lipid yield, and lipid content was done for 33 oleaginous yeast isolates, based on the amount of lipid accumulation. Four isolates (S5, D5, J3 and C9) proved to have high lipid levels. The growth parameters ( lipid content, biomass yield, sugar utilization efficiency, conversion coefficient) were determined during the fermentation time under circumstances of N-limitation medium using a shake flask technique. Lipid synthesis was partially associated with both the linear growth phase and during the stationary phase. The fatty acids profile analysis revealed that the lipid extracted from the four promising yeast isolates mainly contained the principal fatty acids (triacylglyceols, TAGs) as palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2) which is similar to that of vegetable oils. The ratio of saturated and unsaturated fatty acids for the four oleaginous yeasts varied. Isolates S5 and D5 which showed the most potential in lipid production and had the similar fatty acid profile to plant oils, were identified as Candida tropicalis and Pichia kudriavzevii respectively using a molecular genetics technique. Finally, the data show that the identified strains of oleaginous yeast are promising as viable producers of biodiesel | ||
| Keywords | ||
| Biodiesel; Lipids-producing yeast; fatty acid profile; 26S rRNA gene | ||
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