Synthesis of Trehalose by the Erythritol-Producing Yeast Yarrowia lipolytica Co-Displaying Maltooligosyltrehalose Synthase and Maltooligosyltrehalose Trehalohydrolase

Industrial trehalose production faces economic challenges with costly enzyme preparations, prompting the exploration of eco-friendly alternatives. Here, we established a coupled functional sugar production line leveraging erythritol-producing cells as an innovative enzyme preparation for trehalose synthesis. The erythritol-producing Yarrowia lipolytica was modified to express a fusion protein consisting of maltooligosyltrehalose synthase and maltooligosyltrehalose trehalohydrolase from Sulfolobus solfataricus ATCC35092. The engineered strain YlxsT08 was used for the simultaneous synthesis of erythritol and the fusion protein. The yield, production, and productivity of erythritol reached 0.55 g/g of glucose, 166.18 g/L, and 1.98 g/(L·h), respectively, in a 5 L bioreactor. The recycled cells (49.77 U/mg of DCW) exhibited a high catalytic efficiency in the bioconversion of maltodextrin to generate trehalose. The yield, production, and productivity of trehalose reached 0.67 g/g maltodextrin, 134.40 g/L, and 5.60 g/(L·h), respectively, in a 5 L bioreactor. The byproducts were removed by biological purification, and the resulting cells were recycled as catalysts for at least the next 5 rounds of trehalose production. Our novel strategy provides an ecologically sustainable and economically feasible alternative to enzyme combinations in trehalose production, offering a cost-effective and eco-friendly enzyme manufacturing method.