Single Cell Oil Production from Waste Biomass: Review of Applicable Industrial By-Products

Single cell oil (SCO) is an attractive alternative source of oil, which, depending on the fatty acid composition, can be used as a feedstock for biodiesel production, as an ingredient for pharmaceuticals or as a source of essential fatty acids for human and animal consumption. However, the use of SCO is limited due to use of relatively expensive food or feed products in the cultivation of SCO producing microorganisms. In order to reduce SCO production costs, the use of cheaper feedstock such as biodegradable agro-industrial wastes are necessary. At the same time, the microbial treatment of biodegradable wastes ensures the neutralization of environmentally harmful compounds and reduces the negative impact on the environment. Oleaginous microorganisms are capable of fermenting a variety of industrial by-products, waste products and wastewaters, however further discussion on properties of the waste materials is necessary to facilitate the selection of the most appropriate waste materials for SCO production. Thus, this review compares various industrial waste products that can be used as cheap feedstock for the cultivation of SCO producing microorganisms. Industrial waste products, by-products and wastewaters are compared according to their global availability, current use in competing industries, required pre-fermentation treatments, oleaginous microorganism cell concentrations and SCO yields.