Synthesis gas (Syngas), a mixture of CO, H2, and CO2, is a promising renewable feedstock for bio-based production of organic chemicals. Production of medium-chain fatty acids can be performed via chain elongation, utilizing acetate and ethanol as main substrates. Acetate and ethanol are main products of syngas fermentation by acetogens. Therefore, syngas can be indirectly used as a substrate for the chain elongation process.
Syngas fermentation to acetate and ethanol is relatively well studied, and the array of possible products is rapidly expanding. Bio-based production of medium-chain fatty acids (MCFA), such as butyrate and caproate, is of potential interest because they can serve as commodity chemicals. Additionally, their respective alcohols—butanol and hexanol—could serve as potential biofuels. The team of Martijn Diender from Wageningen University report the establishment of a synthetic co-culture consisting of Clostridium autoethanogenum and Clostridium kluyveri to convert CO or syngas into MCFA and their respective alcohols. The co-culture is able to grow using solely CO or syngas as a substrate, and presence of acetate significantly stimulated production rates.
This co-culture poses an alternative way to produce medium-chain fatty acids and higher alcohols from carbon monoxide or syngas and the process can be regarded as an integration of syngas fermentation and chain elongation in one growth vessel.
Find the Biotechnology for Biofuels research article here.