High value-added products derived from crude glycerol via microbial fermentation using Yarrowia clade yeast

Background Contemporary biotechnology focuses on many problems related to the functioning of developed societies. Many of these problems are related to health, especially with the rapidly rising numbers of people suffering from civilization diseases, such as obesity or diabetes. One factor contributing to the development of these diseases is the high consumption of sucrose. A very promising substitute for this sugar has emerged: the polyhydroxy alcohols, characterized by low caloric value and sufficient sweetness to replace table sugar in food production. Results In the current study, yeast belonging to the Yarrowia clade were tested for erythritol, mannitol and arabitol production using crude glycerol from the biodiesel and soap industries as carbon sources. Out of the 13 tested species, Yarrowia divulgata and Candida oslonensis turned out to be particularly efficient polyol producers. Both species produced large amounts of these compounds from both soap-derived glycerol (59.8-62.7 g dm(-3)) and biodiesel-derived glycerol (76.8-79.5 g dm(-3)). However, it is equally important that the protein and lipid content of the biomass (around 30% protein and 12% lipid) obtained after the processes is high enough to use this yeast in the production of animal feed. Conclusions The use of waste glycerol for the production of polyols as well as utilization of the biomass obtained after the process for the production of feed are part of the development of modern waste-free technologies.