|Xylitol production by recombinant Corynebacterium glutamicum under oxygen deprivation.
Appl. Microbiol. Biotechnol. 86: 1057-1066. 2010.
M. Sasaki, T. Jojima, M. Inui and H. Yukawa.
Wild-type Corynebacterium glutamicum produced 0.6 g l(-1) xylitol from xylose at a productivity of 0.01 g l(-1)
h(-1) under oxygen deprivation. To increase this productivity, the pentose
transporter gene (araE) from C. glutamicum ATCC31831 was integrated into the C. glutamicum R chromosome. Consequent disruption of its lactate dehydrogenase gene
(ldhA), and expression of single-site mutant xylose reductase from Candida tenuis (CtXR (K274R)) resulted in recombinant C. glutamicum strain CtXR4 that produced 26.5 g l(-1) xylitol at 3.1 g l(-1) h(-1).
To eliminate possible formation of toxic intracellular xylitol phosphate,
genes encoding xylulokinase (XylB) and phosphoenolpyruvate-dependent fructose
phosphotransferase (PTS(fru)) were disrupted to yield strain CtXR7. The
productivity of strain CtXR7 increased 1.6-fold over that of strain CtXR4.
A fed-batch 21-h CtXR7 culture in mineral salts medium under oxygen deprivation
yielded 166 g l(-1) xylitol at 7.9 g l(-1) h(-1), representing the highest
bacterial xylitol productivity reported to date.