title: Engineering of an L-arabinose metabolic pathway in Corynebacterium glutamicum.
abstract: 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.
authors.affiliation: Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Kizugawa, Kyoto, 619-0292, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Miho
authors.initials: M
authors.lastname: Sasaki
authors.forename: Alain A
authors.initials: AA
authors.lastname: Vertès
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inui
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yukawa
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000693:Anaerobiosis; D001089:Arabinose / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D002264:Carboxylic Acids / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004734:Energy Metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics; D015870:Gene Expression; D005947:Glucose / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000096:biosynthesis / Q000235:genetics; D019802:Succinic Acid / Q000378:metabolism
chemical_list: D002264:Carboxylic Acids; D003470:Culture Media; D029968:Escherichia coli Proteins; D019344:Lactic Acid; D002244:Carbon; D019802:Succinic Acid; D001089:Arabinose; D017853:Phosphotransferases (Alcohol Group Acceptor); C022550:ribulokinase; D005947:Glucose; D019342:Acetic Acid