Biodiesel is a renewable alternative fuel and glycerol as a main byproduct of the manufacturing process. Lipids could be produced from crude glycerol by using yeasts. The ability of 107 yeast strains to utilize glycerol was screened and 92 of these were selected. 60 strains were determined as a potential for lipid production by Sudan Black B staining. After secondary screening 25 of them showed specific growth rates (OD 600), high biomass production and lipid content. These strains were identified as Pichia cactophila, P. fermentans, P. anomala, Rhodotorula mucilaginosa, R. dairenensis, Clavispora lusitaniae, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida glabrata, C. inconspicua, C. albicans, Yarrowia lipolytica with molecular identifications based on ITS and D1/D2 26S rDNA sequences. The results showed that P. cactophila accumulated lipid up to 64.94%, the highest lipid content. C16:0, C18:0, C18:1 and C18:2 essential fatty acids for biodiesel production were detected by GC-MS in the lipids accumulated by all strains. P. cactophila and C. lusitaniae were reported for the first time as lipid-producing yeasts. The results suggest that selected 25 isolates have the ability to grow on crude glycerol and especially P. cactophila produce lipid that has potential use as a feedstock for second generation biodiesel production.

Biodiesel is a renewable alternative fuel and glycerol as a main byproduct of the manufacturing process. Lipids could be produced from crude glycerol by using yeasts. The ability of 107 yeast strains to utilize glycerol was screened and 92 of these were selected. 60 strains were determined as a potential for lipid production by Sudan Black B staining. After secondary screening 25 of them showed speci c growth rates (OD 600), high biomass production and lipid content. These strains were identi ed as Pichia cactophila, P. fermentans, P. anomala, Rhodotorula mucilaginosa, R. dairenensis, Clavispora lusitaniae, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida glabrata, C. inconspicua, C. albicans, Yarrowia lipolytica with molecular identi cations based on ITS and D1/D2 26S rDNA sequences. The results showed that P. cactophila accumulated lipid up to 64.94%, the highest lipid content. C16:0, C18:0, C18:1 and C18:2 essential fatty acids for biodiesel production were detected by GC-MS in the lipids accumulated by all strains. P. cactophila and C. lusitaniae were reported for the rst time as lipid-producing yeasts. The results suggest that selected 25 isolates have the ability to grow on crude glycerol and especially P. cactophila produce lipid that has potential use as a feedstock for second generation biodiesel production. Statement Of Novelty In this study, two step screening was used for determining oleaginous yeasts which metabolize crude glycerol. Screening of new oleaginous microorganisms was important to nd alternative sources of microorganisms to be used in biodiesel production. The 25 tested strains were potentially lipid-producer and generating more than 25.55% (wt/wt) lipids. Crude glycerol, a by-product of the biodiesel industry, was consumed mainly by Pichia cactophila and it was showed the highest yield (64.94%). Hence, the novelty of this study is for the rst time Pichia cactophila and Clavispora lusitaniae being categorized as an oleaginous yeast. Palmitic, stearic, oleic and linoleic acid, essential fatty acids were produced by all strains.

Objective The pulp, remaining after the rose oil and rose water are extracted from the rose, are left around and cannot be utilized economically. It was aimed in this study to produce microbial oil for the first time by means of W. subpeliculosa in medium containing waste rose pulp as a carbon source. The aim of ceasing the high amount of rose pulp to be a pollutant and also making contribution to the biodiesel production, which is a cheap and environmentally-friendly fuel for the national economy. Methods Two applications were made on the waste rose pulp. One of them is that the waste rose pulp has been treated with water. In the second application, it was pretreated with 1% H2SO4. “Box Behnken Experimental Design Method”, having 3 variables with 2 replicates from 15 experimental points, was used in the optimization experiments with the response surface method of the lipid production parameters, containing temperature, and inoculum age and inoculum volume. Results 45% oil yield was obtained from W. subpelliculosus with the waste rose pulp treated with acid and the microbial lipid was produced for the first time in this study. The profile of fatty acid produced consists of 45% palmitic acid, 42,62% stearic acid and 7,38% oleic acid and its fatty acid composition is highly similar to the vegetable oil acids. Conclusion It is considered to be a suitable material for biodiesel production.