Engineering of pentose transport in Corynebacterium glutamicum to improve simultaneous utilization of mixed sugars

• Published in: Applied microbiology and biotechnology 2009-11, Vol.85 (1), p.105-115
• Main Authors: Sasaki, Miho, Jojima, Toru, Kawaguchi, Hideo, Inui, Masayuki, Yukawa, Hideaki
• Format: Article
• Language: English
• Subjects: Aerobiosis; Anaerobiosis; Applied Genetics and Molecular Biotechnology; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological and medical sciences; Biomass energy; Biotechnology; Carbon; Carbon sources; Cellulose; Corynebacterium glutamicum; Corynebacterium glutamicum - genetics; Corynebacterium glutamicum - metabolism; Culture Media - chemistry; E coli; Engineering; Fermentation; Fundamental and applied biological sciences. Psychology; Genes; Genetic Engineering; Glucose; Hexoses - metabolism; Life Sciences; Lignocellulose; Metabolism; Microbial Genetics and Genomics; Microbiology; Monosaccharide Transport Proteins - genetics; Monosaccharide Transport Proteins - metabolism; Oxygen; Pentoses - metabolism; Plasmids; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Studies; Sugar; Yeast
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-009-2065-x

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 , β-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.