The Potential of the Oil-Producing Oleaginous Yeast Rhodotorula mucilaginosa for Sustainable Production of Bio-Oil Energy

Abstract

At the 2021 United Nations Climate Change Conference (COP26), many countries in the world agreed to reach the goal of net-zero greenhouse gas emissions by 2050. This issue constrains energy use, petrochemical use, and related manufacturing production patterns. It is undeniable that the diesel engine of large equipment is still widely used in engineering applications, and it will not disappear in a short time. Many industrial projects still have to face the use of diesel engines. This study was focused on the development of oil-producing microorganisms to generate lipids. The oleaginous yeast Rhodotorula mucilaginosa (R. mucilaginosa) was selected for liquid-state cultivation, and the conditions for growth of the yeast cells were assessed. For the liquid fermentation culture with a fixed inoculation amount of 5%, it was determined that a suitable oil-producing culture was obtained on the sixth day, and the optimum conditions involved a carbon source concentration of 60 g/L, a yeast extract concentration of 0.5 g/L, and a KH2PO4 concentration of 7.0 g/L for each batch of culture experiments. In addition, the extraction method and solvent for the extraction of R. mucilaginosa lipids were chosen. The acid-heat method using the green organic solvent ethyl acetate exhibited the best performance for extraction of yeast lipids under environmentally friendly and safe conditions. The analysis of lipids showed that the fatty acids obtained primarily contained C16:0, C18:1 and C18:2, and especially C18:1 (41%) lipids, indicating that R. mucilaginosa lipids are a good bio-oil source for the production of biodiesel.

The Thermal Properties and Nutritional Value of Biomass of Oleaginous Yeast Rhodotorula sp. during Glucose Fed-Batch Cultivation in Medium with Waste Nitrogen

“…The DSC curves of cocoa powders were obtained with mild, similarly endothermic peaks at temperatures of about 0 °C, regardless of the heat treatment type used for beans [27]. However, the thermal analysis of extracted lipid (not powdered biomass) from Rhodotorula mucilaginosa obtained crystallization DSC curves with two exothermic peaks [28], and the second peak was characterized by a temperature of about −17 °C. Red yeast biomass contains unsaturated fatty acids, and its characterized melting temperature is below 0 °C.…”

“…The DSC curves of cocoa powders were obtained with mild, similarly endothermic peaks at temperatures of about 0 • C, regardless of the heat treatment type used for beans [27]. However, the thermal analysis of extracted lipid (not powdered biomass) from Rhodotorula mucilaginosa obtained crystallization DSC curves with two exothermic peaks [28] The DSC diagrams of red yeast biomass after 168 and 192 h of cultivation in Figures 7 and 8 were presented and characterized in a different course than the previous ones. The first endothermic peaks were observed at −3.53 and −3.82 °C in Figures 7 and 8, respectively.…”

Enhancing the Biodiesel Production by Improving the Yield of Lipids in Wild Strain by Inducing Nitrogen Ion Mutation in Rhodotorula mucilaginosa

“…Different product yields and their accumulation cannot be majorly modified by metabolic engineering due to their specific genetic sequence and metabolic cycle in the microbe. Hence, random mutagenesis plays an important role in causing mutation in microorganisms [8]. There are many artificial mutagenesis methods that target developing the rate of mutation using physical or chemical mutagens.…”