Enhancing erythritol productivity in Yarrowia lipolytica using metabolic engineering

- Metabolic engineering strategies permit improvement of erythritol synthesis.
- Overexpression of GUT1 and TKL1 increase erythritol productivity by 75%.
- Disruption of EYK1, encoding erythrulose kinase, prevent erythritol catabolism.
- Culturing time needed to achieve maximum erythritol concentration was reduced by 40%.

Erythritol (1,2,3,4-butanetetrol) is a four-carbon sugar alcohol with sweetening properties that is used by the agrofood industry as a food additive. In this study, we demonstrated that metabolic engineering can be used to improve the production of erythritol from glycerol in the yeast Yarrowia lipolytica. The best results were obtained using a mutant that overexpressed GUT1 and TKL1, which encode a glycerol kinase and a transketolase, respectively, and in which EYK1, which encodes erythrulose kinase, was disrupted; the latter enzyme is involved in an early step of erythritol catabolism. In this strain, erythritol productivity was 75% higher than in the wild type; furthermore, the culturing time needed to achieve maximum concentration was reduced by 40%. An additional advantage is that the strain was unable to consume the erythritol it had created, further increasing the process's efficiency. The erythritol productivity values we obtained here are among the highest reported thus far.