Recycling of lignocellulosic waste materials to produce high-value products: single cell oil and xylitol

Application of microorganisms with ability of using environmental wastes such as lignocellulosic materials for converting them to high-value products is important from economical point of view. Valuable products such as single cell oil (SCO) have a high potential to be used in various industrial fields including biodiesel production. Other important products are polyalcohols like xylitol, which are applicable in the food and pharmaceutical industries. In this study, Rhodotorula yeast was isolated from the leaves of Benjamin. Afterward, SCO production was evaluated in a nitrogen-limited medium, and the obtained oil was analyzed by gas chromatography–mass spectrometery. Moreover, xylitol was produced in a media containing xylose and analyzed by high-performance liquid chromatography technique. The yeast strain was identified using polymerase chain reaction method. SCO and xylitol production was also evaluated in a medium containing lignocellulosic materials and other forestry residues. This strain produced SCO and dry biomass of 9.7 and 16.14 g/L, respectively. In addition, in a medium with 140 g/L of xylose, xylitol production was found to be 49.28 g/L. Among waste materials, lipid content of 49 % on grass hydrolysate was found to be incredible. The obtained strain was identified as Rhodotorula mucilaginosa. The results of this study show that by the isolation of yeast with the potential of making use of waste materials, high-value products can be obtained. Therefore, it can be concluded that the mentioned bioprocess has not only environmental benefits but also is very important from economical view.