Single Cell Oil (SCO) Production by Rhodotorula mucilaginosa and Its Environmental Benefits

Abstract

Microbial oil has high similarity to the oil obtai ned from plants and animals. They are renewable sources that can be used for different pu rposes such as production of biofuels. Biofuels are renewable, biodegradable, and nontoxic , which makes them highly environmentally friendly. Producing oil from yeasts has more advantages than that from plants. Accordingly, isolation of oleaginous yeasts with high ability of lipid production is highly valuable. A total of 138 yeasts were isolate d for the purpose of this study. From this amount, 35 were capable of producing lipid. After e xtracting lipid, the best strain was selected and, by using PCR method, identified as Rhodotorula mucilaginosa . Optimization was done using the design of experiments; Qualitek- 4 (W32b) software was used for analyzing the experimental data. According to the r esults, Rhodotorula mucilaginosa proved to comprise lipid, dry biomass, and lipid pr oductivity at levels of 10.97 g L -1 , 18.84 g L - 1, and 58.2% in optimized conditions, respectively. Lipid content on corn stalk and wheat straw hydrolysate was 36.9 and 41.8%, respect ively. The extracted lipid was analyzed by FTIR spectroscopy and gas chromatograph y-mass spectrometry (GC-MS). The study showed high potential of lipid production in Rhodotorula mucilaginosa and also high efficiency of using Taguchi design in optimiza tion of medium condition; therefore, by using this method, the optimization process can be done as best as possible. The economic values of microbial lipid production become more fa vorable when waste materials with zero or negative economic value are utilized as car bon source. Using bioprocesses such as microbial lipid production from waste materials, th e problem of shortage of energy resources, and also air pollutions caused by fossil fuels, could be eliminated. Keywords: Air pollution , Biofuels , Microbial lipid.