Biofuels production (ethanol, butanol, hexanol) from renewable sources

Resumo

The search for new energy sources or fuels has increased in recent years. Besides, the increasing demand and greater shortage of conventional fuels, creates the need to replace them by renewable energy sources. Some possible renewable energy sources are (higher) alcohols such as ethanol, butanol, and hexanol. The biological production of ethanol and higher alcohols can be a good and inexpensive way for the obtention of new renewable energy sources. The anaerobic fermentation of waste materials or waste gases is an energy-inexpensive and feedstock-flexible technology for the production of those bioalcohols. The use of those raw materials in biorefineries has two major advantages : it is an efficient method for the elimination of pollutants and compounds with a greenhouse effect (CO, CO2) and it allows to produce solvents with a high commercial value. The main objective of this dissertation is the obtention of higher alcohols using different carbon sources (glucose, carbon monoxide and syngas) with the anaerobic bacterium Clostridium carboxidivorans as biocatalyst. The experimental results are reported in the different chapters of this dissertation, aiming at optimizing the fermentation conditions and operating parameters of the bioconversion of these different carbon sources into ethanol and higher alcohols.