Green Energy to Sustainability: Strategies for Global Industries

10Advanced Fermentation Technologies: Conversion of Biomass to Ethanol by Organisms Other than Yeasts, a Case for Escherichia coli

K. T. Shanmugam, Lorraine P. Yomano, Sean W. York, and Lonnie O. Ingram

Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA

CHAPTER MENU

• Introduction
• Zymomonas mobilis
• Escherichia coli
• Osmotic Stress of High Sugar Concentration
• Inhibitor‐Tolerant Ethanologenic E. coli
• Engineering Bacterial Biocatalysts Other than E. coli for the Production of Ethanol Using the PDC/ADH Pathway
• Ethanol Production by Non‐PDC Pathways
• Partition of Carbon at the Pyruvate Node
• Other Metabolic Pathways that Contribute to Ethanol Production
• Perspectives
• Acknowledgements
• References

10.1 Introduction

The fermentation of sugars by Saccharomyces cerevisiae to ethanol is described elsewhere, (Chapter 13) in this monograph. The critical enzymes of this pathway are pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) that convert pyruvate produced by glycolysis to ethanol and CO₂ in stoichiometric amounts. Any anaerobe or facultative anaerobe endowed with these two genes is expected to ferment sugars to ethanol at yields that are comparable to that of yeast. However, yeast dominates the ethanol fermentation industry due to its historic significance. Although evidence on yeast fermentation of fruit juices to ethanol goes back over 7000 years (McGovern et al. 2004), the history of fermentation of concentrated sugar solutions ...