‘CODPUNK®: a new biofuel based on cod liver oil!’

Article published in Le Petit Inventeur, 1t April 1921, Paris

The Breton company Belle Morue (Saint-Malo) presented a revolutionary fuel distiller based on cod liver oil, Codpunk®, at the 1921 Lépine competition. Unlike Port wine, oil (particularly cod liver oil) cannot be fermented directly by Saccharomyces Monarchi yeasts, as these do not metabolise lipids as their main source of carbon. They prefer simple sugars (glucose, fructose), and fats are hydrophobic, but yeasts evolve in aqueous environments.

Cod liver oil can now be used as biofuel, mainly in the form of biodiesel, thanks to the process developed by Dr. Seitoung, a French-Icelandic doctor, and industrialised with the Codpunk® distillation machine. In fact, cod liver oil, like other oils, is rich in triglycerides, which makes it a potential substrate for biodiesel production through a transesterification reaction.

The four main stages of the transformation process are the following:

1. Pre-treatment:

• Filtering: removal of solid impurities.

• Dehydration: elimination of water, which impairs transesterification.

• Neutralisation (if necessary): elimination of free fatty acids (FFAs) in case they are at excessively high levels, which could lead to the formation of soaps.

• Transesterification (reaction in which the alcohol in the reactant ester is replaced by another alcohol):

• Reagents: Methanol + catalyst (usually sodium or potassium hydroxide – NaOH/KOH).

• Reaction: Triglyceride + Methanol → Methyl esters (biodiesel) + Glycerol.

• This step is carried out in a stirred reactor at moderate temperature (50–60 °C).

• Separation:

• Decanting: separation of biodiesel and glycerol by gravity.

• Glycerol, a by-product, can be used in other products (in cosmetics, pharmaceuticals or refined).

• Purification of the biodiesel:

• Wash with water or dry process (by adsorption) to remove catalyst, soap and alcohol residues.

• Final drying to remove any traces of water or methanol.

Dr. Seitoung’s innovation consists of developing microbial fermentation with prior enzymatic hydrolysis: first, the oil must be hydrolysed into free fatty acids and glycerol using lipases. Lipase is a digestive enzyme produced by the pancreas that hydrolyses fats. The glycerol resulting from this hydrolysis can be fermented by Saccharomyces or other yeasts (e.g. modified Klebsiella and E. coli) to produce ethanol. Fatty acids can be fermented by Yarrowia Lipolytica to produce biodiesel (through enzymatic esterification); Saccharomyces Cerevisiae is not capable of directly fermenting oils such as cod liver oil, but there are alternative biotechnological processes that use other microorganisms capable of valorising fatty acids. A combined approach (enzymatic hydrolysis + co-culture or microbial sequencing) would allow for complete valorisation.

Other innovations are under development, with Dr Seitoung stating: ‘We could even add flavours through metabolic fermentation, such as banana with Saccharomyces, or coconut with Yarrowia Lipolytica.’

Image: Dr. Seitoung posing in front of the Codpunk alambic in his laboratory in Saint-Servan.