Restoring of Glucose Metabolism of Engineered Yarrowia lipolytica for Succinic Acid Production via a Simple and Efficient Adaptive Evolution Strategy

Succinate dehydrogenase inactivation in Yarrowia lipolytica has been demonstrated for robust succinic acid production, whereas the inefficient glucose metabolism has hindered its practical applications In this study, a simple and efficient adaptive evolution strategy via cell immobilization was conducted in shake flasks, with an aim to restore the glucose metabolism of Y. lipolytica mutant PGC01003. After 21 days with 14 generations evolution, glucose consumption rate increased to 0.30 g/L/h in YPD medium consisting of 150 g/L initial glucose concentration, while poor yeast growth was observed in the same medium using the initial strain without adaptive evolution. Succinic acid productivity of:the evolved strain also increased by 2.3 fold, with stable cell growth in YPD medium with high initial glucose concentration. Batch fermentations resulted in fmal succinic acid concentrations of 65.7 g/L and 87.9 g/L succinic acid using YPD medium and food waste hydrolysate, respectively. The experimental results in this study show that a simple and efficient strategy could facilitate the glucose uptake rate in succinic acid fermentation using glucose-rich substrates.