Waste Conversion into a Sweetener—Development of an Innovative Strategy for Erythritol Production by Yarrowia lipolytica

The study proposed the innovative low-cost strategy for erythritol production by Yarrowia lipolytica through developing a simple medium based on industrial waste by-products and a natural method for culture broth purification. Results obtained proved that corn steep liquor might successfully replace traditional sources of nitrogen and other nutrients without compromising activities of the enzymes responsible for erythritol production and its production level. As a consequence, a production process was performed where Y. lipolytica A-6 was able to produce 108.0 g/L of erythritol, with a production rate of 1.04 g/Lh and a yield of 0.45 g/g of the medium containing exclusively 220 g/L of crude glycerol derived from biodiesel production and 40 g/L of corn steep liquor. Moreover, a comparable concentration of erythritol (108.1 g/L) was obtained when a part of crude glycerol was exchanged for the crude fraction of fatty acids in the two-steps process. Next, the collected post-fermentation broths were used in the culture with Y. lipolytica Wratislavia K1 for natural purification. The process resulted in a high increase of erythritol selectivity from 72% to 97% and in the production of 22.0 g/L of biomass with 40.4% protein content, which enables its use as an attractive animal feedstuff.