Technology of efficient continuous erythritol production from glycerol

Erythritol production in chemostat culture from pure and crude glycerol with different nitrogen sources by Yarrowia lipolytica Wratislavia K1 was investigated. Moreover, a process of erythritol purification based on ion exchange is proposed. The highest erythritol production (103.4 g L−1 with a volumetric erythritol production rate of 1.12 g L−1 h−1 and a yield of 0.52 g g−1) was obtained by applying an inorganic nitrogen source (4.6 g L−1 of ammonium sulfate). Very promising results were also obtained when pure glycerol was replaced with crude glycerol as a carbon source. During this culture yeast produced 81.9 g L−1 of erythritol, which corresponded to a 0.9 g L−1 h−1 volumetric erythritol production rate and a yield of erythritol production of 0.4 g g−1. The fermentation broth was desalinated and decolorized by ion exclusion, ion exchange and sorption on activated carbon. The final solution contained only erythritol. The presented technology follows the vision of a circular economy by turning waste into products and using renewable materials as a feedstock. This study supports the potential of the industrially relevant wild type Yarrowia lipolytica strain for intensified and efficient erythritol production. The proposed technology is ecofriendly, requires a small number of purification steps and generates low amount of wastes. The final solution is rich in erythritol and can be applied directly as a sweet low-calorie food additive.