Syngas Fermentation: Microbial Catalysis Using Clostridium ljungdahlii

Biomass is a huge source of high added value products such as chemicals and fuels. In the nowadays world concerns that every day needs more power, fuel production has become critical and, when combined with environmental issues, it becomes imperative to search for new production routes for biofuels from renewable sources such as biomass. Currently, biofuels are commercially produced from sugar, starch, and oil seed.

There are two main pathways for the production of biofuels, especially ethanol from lignocellulosic biomass: the biochemical route and the thermochemical route. The thermochemical route, which, by gasification, converts the biomass to synthesis gas (CO and H₂). The synthesis gas (syngas) itself is a high value product, but it can be further processed for biofuel production using chemical catalysts in a process known as Fischer-Tropsch (FT), or using microbial catalysts in a process known as fermentation of syngas.

In this work, the aim was to study the ability of Clostridium ljungdahlii (DSM 13528) for the production of bioethanol and acetic acid from Syngas. The conditions of the medium, temperature and pH were recommended for optimal growth of the microorganism. The fermentations were made in the biological reactor 415 Bioflow of New Brunscwick. It was obtained the product profiles in respect to time, continuously feeding syngas with a known composition. The fermentation products were analyzed by high performance liquid chromatography, and the gas at the outlet of the fermenter by gas chromatography.