Engineering of pentose transport in Corynebacterium glutamicum to improve simultaneous utilization of mixed sugars.
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 bglF317A, 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.
Sasaki
Miho
M
Research Institute of Innovative Technology for the Earth, 9-2, Kizugawadai, Kizugawa, Kyoto, 619-0292, Japan.
Jojima
Toru
T
Kawaguchi
Hideo
H
Inui
Masayuki
M
Yukawa
Hideaki
H
D000332:Aerobiosis; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005818:Genetic Engineering; D006601:Hexoses / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D010429:Pentoses / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
C109577:AraE protein, bacteria; D001426:Bacterial Proteins; D003470:Culture Media; D006601:Hexoses; D009004:Monosaccharide Transport Proteins; D010429:Pentoses; D011994:Recombinant Proteins