Conversion of glucose‐xylose mixtures to pyruvate using a consortium of metabolically engineered Escherichia coli |
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Authors: | Neda Maleki Mohammad Safari Mark A Eiteman |
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Institution: | 1. Department of Food Science, Engineering and Technology, University of Tehran, Karaj, Iran;2. School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA, USA |
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Abstract: | Two strains of Escherichia coli were engineered to accumulate pyruvic acid from two sugars found in lignocellulosic hydrolysates by knockouts in the aceE, ppsA, poxB, and ldhA genes. Additionally, since glucose and xylose are typically consumed sequentially due to carbon catabolite repression in E. coli, one strain (MEC590) was engineered to grow only on glucose while a second strain (MEC589) grew only on xylose. On a single substrate, each strain generated pyruvate at a yield of about 0.60 g/g in both continuous culture and batch culture. In a glucose‐xylose mixture under continuous culture, a consortium of both strains maintained a pyruvate yield greater than 0.60 g/g when three different concentrations of glucose and xylose were sequentially fed into the system. In a fed‐batch process, both sugars in a glucose‐xylose mixture were consumed simultaneously to accumulate 39 g/L pyruvate in less than 24 h at a yield of 0.59 g/g. |
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Keywords: | Chemostat Glucose Lignocellulosic hydrolysate Pyruvic acid Xylose |
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