Screening the Potential Oleaginous Yeast Strains for Lipid Accumulation on Glycerol, a By-Product from Biodiesel Production

Abstract

In this work, glycerol, a by-product from palm oil-biodiesel plant, was used as an alternative substrate for cultivating oleaginous yeast Rhodotorula glutinis (R. glutinis). Three R. glutinis strains were selected to compare the biomass production and lipid accumulation potencies namely, NBRC 0695, NBRC 1099 and NBRC 1501. The results found that R. glutinis NBRC 1099 was identified as the best lipid accumulation strain among the three strains tested, with a total biomass of 0.17 g/L and a lipid content of 40.80% at 24 hours when using the concentration of glycerol in the medium at 30 g/L. Furthermore, the optimization of cultivation conditions for the best oil producing strain obtained was evaluated using response surface methodology (RSM). A 5-level 2-factor central composite design (CCD) was used to build the statistical model. The optimum cultivation conditions for R. glutinis NBRC 1099 found in this study was: the glycerol concentration in the medium (34.14 g/L), the inoculum volume (1.6 mL; 4.5 x 107 cell) and incubated at 30°C for 24 hours. This optimum condition gave 43.65% of the lipid content. Five fatty acids were found in the lipid produced from this condition namely, myristic acid (0.72%), palmitic acid (19.64%), stearic acid (54.59%), oleic acid (19.44%), linoleic acid (2.04%) and linolenic acid (3.56%).