BIOLOGICAL PRODUCTION OF ETHANOL FROM COAL SYNTHESIS GAS - MEDIUM DEVELOPMENT STUDIES

The anaerobic bacteria Clostridium ljungdahlii produces ethanol and acetate from CO, CO2, and H-2 in synthesis gas. Early studies with the bacterium showed that relatively high concentrations of ethanol could be produced by lowering the fermentation pH and eliminating yeast extract from the medium in favor of a defined medium. This article presents the results from a medium development study based on the aerobic bacterium Escherichia coli. The results of continuous-reactor studies in a continuously stirred tank reactor (CSTR) with and without cell recycle are shown to demonstrate the utility of this improved medium.