Accumulation of d-Glucose from Pentoses by Metabolically Engineered Escherichia coli |
| |
| Authors: | Tian Xia Qi Han William V Costanzo Yixuan Zhu Jeffrey L Urbauer Mark A Eiteman |
| |
| Institution: | aBioChemical Engineering, College of Engineering, University of Georgia, Athens, Georgia, USA;bDepartment of Chemistry, University of Georgia, Athens, Georgia, USA |
| |
| Abstract: | Escherichia coli that is unable to metabolize d-glucose (with knockouts in ptsG, manZ, and glk) accumulates a small amount of d-glucose (yield of about 0.01 g/g) during growth on the pentoses d-xylose or l-arabinose as a sole carbon source. Additional knockouts in the zwf and pfkA genes, encoding, respectively, d-glucose-6-phosphate 1-dehydrogenase and 6-phosphofructokinase I (E. coli MEC143), increased accumulation to greater than 1 g/liter d-glucose and 100 mg/liter d-mannose from 5 g/liter d-xylose or l-arabinose. Knockouts of other genes associated with interconversions of d-glucose-phosphates demonstrate that d-glucose is formed primarily by the dephosphorylation of d-glucose-6-phosphate. Under controlled batch conditions with 20 g/liter d-xylose, MEC143 generated 4.4 g/liter d-glucose and 0.6 g/liter d-mannose. The results establish a direct link between pentoses and hexoses and provide a novel strategy to increase carbon backbone length from five to six carbons by directing flux through the pentose phosphate pathway. |
| |
| Keywords: | |
|
|
