Engineering of pentose transport in Corynebacterium glutamicum to improve simultaneous utilization of mixed sugars.
Appl. Environ. Microbiol. 85: 105-115. 2009.
M. Sasaki, T. Jojima, H. Kawaguchi, M. Inui and H. Yukawa.

Corynebacterium glutamicum strains CRA1 and CRX2 are able to grow on L: -arabinose and D: -xylose, respectively, as sole carbon sources. Nevertheless, they exhibit the major shortcoming that their sugar consumption appreciably declines at lower concentrations of these substrates. To address this, the C. glutamicum ATCC31831 L: -arabinose transporter gene, araE, was independently integrated into both strains. Unlike its parental strain, resultant CRA1-araE was able to aerobically grow at low (3.6 g.l(-1)) L: -arabinose concentrations. Interestingly, strain CRX2-araE grew 2.9-fold faster than parental CRX2 at low (3.6 g.l(-1)) D: -xylose concentrations. The corresponding substrate consumption rates of CRA1-araE and CRX2-araE under oxygen-deprived conditions were 2.8- and 2.7-fold, respectively, higher than those of their respective parental strains. Moreover, CRA1-araE and CRX2-araE utilized their respective substrates simultaneously with D: -glucose under both aerobic and oxygen-deprived conditions. Based on these observations, a platform strain, ACX-araE, for C. glutamicum-based mixed sugar utilization was designed. It harbored araBAD for L: -arabinose metabolism, xylAB for D: -xylose metabolism, D: -cellobiose permease-encoding bglF ( 317A ), beta-glucosidase-encoding bglA and araE in its chromosomal DNA. In mineral medium containing a sugar mixture of D: -glucose, D: -xylose, L: -arabinose, and D: -cellobiose under oxygen-deprived conditions, strain ACX-araE simultaneously and completely consumed all sugars.