Overexpression of TKL1 in Yarrowia lipolytica Increases Erythritol Production

Erythritol, a four-carbon polyol synthesized by microorganisms as an osmoprotectant, is a natural sweetener produced on an industrial scale. Studies have shown that erythritol synthesis in yeast occurs via the pentose phosphate pathway (PPP). Yarrowia lipolytica is a good host for converting inexpensive glycerol into a value-added product such as erythritol.

Aleksandra M. Mirończuk from the Wroclaw University of Environmental and Life Sciences functionally overexpressed four genes involved in the pentose phosphate pathway (PPP): gene encoding transketolase (TKL1), gene encoding transaldolase (TAL1), gene encoding glucose-6-phosphate dehydrogenase (ZWF1), and gene encoding 6-phosphogluconate dehydrogenase (GND1).

Results show that the crucial gene for erythritol synthesis in Y. lipolytica is the TKL1, which encodes transketolase. Overexpression of the gene resulted in doubling in erythritol synthesis. Moreover, overexpression of TKL1 allows for efficient production of erythritol independently from the supplied dissolved oxygen.

This work presents the importance of the PPP in erythritol synthesis and the feasibility for commercial production of erythritol from glycerol via Y. lipolytica.