Optimization of Lipid Production of Rhodosporidium toruloides from Various Substrates

Abstract

Background and Aim: In recent years, bioenergy has received a lot of attention from a technical point of view due to its ability to use reversible resources and its applicability worldwide. Biodiesel is a non-toxic, safe, renewable, and degradable fuel that is obtained from natural sources, such as vegetable oils, food waste oils, animal fats, algae, and microorganisms. This study aimed to optimize the lipid production of Rhodosporidium toruloides as a biofuel from different substrates. Materials and Methods: In this experimental laboratory study, after lipid extraction from Rhodosporidium toruloides CECT1137, cell biomass, nitrogen, and sugar consumption were measured according to the Bly and Dyer method. Then, using gas chromatography, the produced lipid compounds were identified, and lipid production was optimized by the one-factor method (type of nitrogen source and KH2PO4) and the Taguchi method (carbon and nitrogen source, temperature, pH, centrifuge, and time). Finally, the feasibility of mutation was investigated using UV to optimize lipid production. Results: The amount of lipid produced by Rhodosporidium toruloides was 4.95 g/l, which, after optimization by the Taguchi method, reached 8.54 g/l. Cell biomass, residual nitrogen, and consumed sugar were measured as 14.05, 0.19, and 28.85 g/l, respectively. Optimal production conditions were estimated by Taguchi, including 80 g/l carbon source, 1 g/l nitrogen source, 25 ° C, pH = 5.5, centrifuge at 180 rpm, and 96 hours. Most lipids produced were oleic acid and palmitic acid. Lipid production increased after UV exposure. Conclusion: The results showed that Rhodosporidium toruloides can accumulate a significant amount of lipid in its cells and can be a good alternative to plants and other sources of fuel production.