Enhanced production of 2,3-butanediol from xylose by combinatorial engineering of xylose metabolic pathway and cofactor regeneration in pyruvate decarboxylase-deficient Saccharomyces cerevisiae.

The aim of this study was to produce 2,3-butanediol (2,3-BDO) from xylose efficiently by modulation of the xylose metabolic pathway in engineered Saccharomyces cerevisiae. Expression of the Scheffersomyces stipitis transaldolase and NADH-preferring xylose reductase in S. cerevisiae improved xylose consumption rate by a 2.1-fold and 2,3-BDO productivity by a 1.8-fold. Expression of the Lactococcus lactis noxE gene encoding NADH oxidase also increased 2,3-BDO yield by decreasing glycerol accumulation. Additionally, the disadvantage of C2-dependent growth of pyruvate decarboxylase-deficient (Pdc-) S. cerevisiae was overcome by expression of the Candida tropicalis PDC1 gene. A fed-batch fermentation of the BD5X-TXmNP strain resulted in 96.8g/L 2,3-BDO and 0.58g/L-h productivity from xylose, which were 15.6- and 2-fold increases compared with the corresponding values of the BD5X strain. It was concluded that facilitation of the xylose metabolic pathway, oxidation of NADH and relief of C2-dependency synergistically triggered 2,3-BDO production from xylose in Pdc-S. cerevisiae.