Ethanol production from syngas

Ethanol can be used as a biofuel or as a platform chemical. Though it is often produced from compounds such as ethylene, it can also be obtained through either the catalytic conversion or the bioconversion of syngas. The direct catalytic conversion of syngas to ethanol is possible, though not yet sufficiently optimized in terms of yields, selectivity, and efficiency to allow for its commercial development. Instead, indirect catalytic conversion of syngas, through other intermediate compounds (e.g., methanol), has recently been scaled-up to commercial scale. On the other side, the bioconversion or fermentation of syngas into ethanol by acetogenic bacteria is another interesting alternative approach, which has also recently reached commercialization. While catalytic reactions generally require high pressures and temperatures, as well as expensive catalysts, bioprocesses are optimized at near room temperature and pressure and rely on the activity of innocuous bacteria as cheap biocatalysts.