Improving microbial oil production with standard and native oleaginous yeasts by using Taguchi design

Abstract

Production of microbial oil has attracted a great attention in recent years. The potential of lipid production by the yeast strains is the reason for using microorganisms for biodiesel production. Microbial lipid has high similarity to the oil obtained from plants and animals in type and composition. Production of oil from yeasts must be economical, so optimization of the cultivation condition to reach higher production must be done. Native oleaginous yeast, Cryptococcus albidus, was isolated from soil by the nitrogen-limited medium and screened by Nile red staining. Yarrowia lipolytica DSM 8218 was used for lipid production as a standard strain. C. albidus was an excellent oleaginous yeast, and the lipid quantity, dry biomass and lipid productivity of this strain were 11.81 g/l, 19.65 g/l and 60.1 %, respectively, in shaking flask cultivation at 150 rpm and 25 °C in nitrogen-limited medium containing per liter 75 g glucose, 1 g (NH4)2SO4, 1 g yeast extract, 3 g KH2PO4, 1.5 g MgSO4.7H2O, 0.15 g CaCl2, 0.06 g MnSO4.H2O, 0.02 g ZnSO4.7H2O and 0.15 g FeCl3.6H2O with pH adjusted to 6.5. Fourier transform infrared spectroscopy was used for analyzing and confirming the production of microbial oil in this study.