Fed-batch cultures for microbial oils production by yeast Rhodotorula glutinis from glycerol

Abstract

The demand for liquid renewable fuels used in the transportation sector, such as ethanol, biodiesel and bio-kerosene, has grown in recent years. The production of lipid-based biofuels, such as biodiesel and bio-kerosene, has as one of its main raw materials vegetable oils. An alternative to replace these oils are oils of microbial origin, which can be obtained from autotrophic microorganisms such as microalgae and cyanobacteria, or heterotrophic microorganisms such as filamentous fungi and yeasts. The main advantages of microbial oil production by heterotrophic cultivation, compared to other processes, refers to a non-seasonally and its high productivity per unit area. To obtain the microbial oils by yeast, a possible carbon source is glycerol, the main by-product of biodiesel production. The use of this by-product is of great interest as it contributes to the consolidation of biorefineries based on lipids. Within this context, the present project aims to contribute to the development of technologies aimed at the production of microbial oils under heterotrophic conditions using glycerol as substrate. In a first step, a study of cultivation conditions will be carried out, aiming to maximize lipid productivity, employing experimental planning methodology to evaluate the influence of substrate concentration, carbon / nitrogen ratio, initial pH and inoculum concentration. In a second step will be evaluated different yeast cultures strategies in fed-batch process, varying the form of food, seeking to achieve high cell density conditions, and provide high productivity in microbial oils. (AU)