Article Abstract:
The introduction of the Escherichia coli pmi gene into the gram negative bacteria Zymomonas mobilis leads to phosphomannose-isomerase expression allowing Z. mobilis to use mannose as the carbon source for growth. The glucose facilitator protein in the bacterial strain is responsible for the mannose uptake, and can be used as a selective marker for the strain. The cloned frk gene in Z. mobilis expresses mannose-phosphorylating activity. The expression of the Z. mobilis glf and the frk genes restores growth on mannose in E. coli strains, in the presence of phosphomannose-isomerase activity.
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Article Abstract:
The extraction of five genes from Escherichia coli and their introduction into Zymomonas mobilis produces an arabinose-fermenting Zymomonas mobilis strain. This is done under the control of constitutive promoters which allow the genes to express themselves even in the presence of glucose. The genetically engineered strain grows on L-arabinose, which acts as the only source of C. The strain produces ethanol from L-arabinose at 98% of the theoretical efficiency. This suggests that arabinose is metabolized completely to ethanol with just a few by-products.
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Article Abstract:
Microbiological research using radioactive fructose shows that fructose incorporation by the gram-negative, obligately fermentative bacterium Zymomonas mobilis CP4 is reduced in the presence of glucose. However, the glucose-reducing effect is far less in vivo than in vitro. Evidence suggests that a single facilitated diffusion transport system is used in glucose and fructose uptake. Z. mobilis may accumulate fructose in the presence of high glucose concentrations so that it can produce sorbitol.
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