초록
<P><B>Abstract</B></P> <P>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 <I>Saccharomyces cerevisiae</I>. Expression of the <I>Scheffersomyces stipitis</I> transaldolase and NADH-preferring xylose reductase in <I>S. cerevisiae</I> improved xylose consumption rate by a 2.1-fold and 2,3-BDO productivity by a 1.8-fold. Expression of the <I>Lactococcus lactis noxE</I> gene encoding NADH oxidase also increased 2,3-BDO yield by decreasing glycerol accumulation. Additionally, the disadvantage of C<SUB>2</SUB>-dependent growth of pyruvate decarboxylase-deficient (Pdc<SUP>−</SUP>) <I>S. cerevisiae</I> was overcome by expression of the <I>Candida tropicalis PDC1</I> 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 C<SUB>2</SUB>-dependency synergistically triggered 2,3-BDO production from xylose in Pdc<SUP>−</SUP> <I>S. cerevisiae</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Overexpression of <I>TAL1</I> improved 2,3-BDO productivity from xylose. </LI> <LI> Expression of mutant XR contributed to enhancing xylose consumption rate. </LI> <LI> Expression of <I>noxE</I> increased 2,3-BDO yield from xylose by reducing glycerol production. </LI> <LI> Introduction of <I>C. tropicalis PDC1</I> allowed to escape from C<SUB>2</SUB>-auxotrophy. </LI> <LI> Optimal fed-batch fermentation resulted in 96.8g/L of 2,3-BDO from xylose. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>2,3-Butanediol biosynthetic pathway from xylose and glucose in recombinant C<SUB>2</SUB>-independent and Pdc-deficient <I>S. cerevisiae;</I> The superscripts in the enzyme names present as follows: <I>Bs</I>, <I>Bacillus subtilis; Ct</I>, <I>Candida tropicalis; Ll</I>, <I>Lactococcus lactis; Ss, Scheffersomyces stipitis</I>; The names of enzymes are abbreviated as follow: XR, xylose reductase; XDH, xylitol dehydrogenase; XK, xylulose kinase; TAL1, transaldolase; ALS, α-acetolactate synthase; ALDC, α-acetolactate decarboxylase; BDH, 2,3-BDO dehydrogenase; PDC, pyruvate decarboxylase; NoxE, NADH oxidase.</P> <P>[DISPLAY OMISSION]</P>