Accumulation of D-Glucose from Pentoses by Metabolically Engineered Escherichia coli

作者:Xia Tian; Han Qi; Costanzo William V; Zhu Yixuan; Urbauer Jeffrey L; Eiteman Mark A*
来源:Applied and Environmental Microbiology, 2015, 81(10): 3387-3394.
DOI:10.1128/AEM.04058-14

摘要

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.

  • 出版日期2015-5