Evaluation of In Vitro Lipid and Carotenoid Synthesis by Yeast, Rhodosporidium Diobovatum

Recently, lipid and carotenoid synthesis by microorganism has been considered as the alternative method to the conventional animal and plant based resources. This study is focused on the ability of in vitro synthesis of these high-value products using Rhodosporidium diobovatum yeast.
Rate of biomass production, lipid and carotenoid content, were investigated for cell cultures in nitrogen-limiting medium containing glucose (217 mM) or glycerol (434 mM) during a five-day period of post inoculation (pi). The experiments were carried out at 30 °C and 150 rpm.
Regarding the biomass yield (g dcw/g carbon consumed), no significant variation (5% probability) was observed in glucose (0.72±0.01) and glycerol (0.73±0.03) cell cultures after 120 h, but the glucose cultures synthesized more significant content of lipid at different time-points, and reached to a slightly greater amounts of lipid (46.29 ± 0.92 % dcw) than the glycerol cultures (44.57 ± 0.49 % dcw) at 120 h. In addition, the quantity of carotenoid production in glucose cultures was higher than those in glycerol cultures at 120 h pi (1987 ± 249 µg/L, versus 1758 ± 15 µg/L, respectively). Glucose grown cells produced 5.11% of mono-unsaturated fatty acid (MUFA) and 3.7% of poly-unsaturated fatty acid (PUFA) more than those in glycerol fed cultures, whereas the saturated fatty acid (SFA) were synthesized 8.21% more in the glycerol cultures.
The study shows extensive accumulation of neutral lipids and carotenoid, and suggests that R. diobovatum could be an effective strain for production of feedstock for food, fuel and bio industries from various substrates.