Engineering of an L-arabinose metabolic pathway in Corynebacterium glutamicum.
Appl. Microbiol. Biotechnol. 77: 1053-1062. 2008.
H. Kawaguchi, M. Sasaki, A.A. Vertès, M. Inui and H. Yukawa.

Corynebacterium glutamicum was metabolically engineered to broaden its substrate utilization range to include the pentose sugar L: -arabinose, a product of the degradation of lignocellulosic biomass. The resultant CRA1 recombinant strain expressed the Escherichia coli genes araA, araB, and araD encoding L: -arabinose isomerase, L: -ribulokinase, and L: -ribulose-5-phosphate 4-epimerase, respectively, under the control of a constitutive promoter. Unlike the wild-type strain, CRA1 was able to grow on mineral salts medium containing L: -arabinose as the sole carbon and energy source. The three cloned genes were expressed to the same levels whether cells were cultured in the presence of D: -glucose or L: -arabinose. Under oxygen deprivation and with L: -arabinose as the sole carbon and energy source, strain CRA1 carbon flow was redirected to produce up to 40, 37, and 11%, respectively, of the theoretical yields of succinic, lactic, and acetic acids. Using a sugar mixture containing 5% D: -glucose and 1% L: -arabinose under oxygen deprivation, CRA1 cells metabolized L: -arabinose at a constant rate, resulting in combined organic acids yield based on the amount of sugar mixture consumed after D: -glucose depletion (83%) that was comparable to that before D: -glucose depletion (89%). Strain CRA1 is, therefore, able to utilize L: -arabinose as a substrate for organic acid production even in the presence of D: -glucose.