The work carried out by the PEEP team of TBI around a bacterium involved in the production of butanol could allow, in the long term, to industrialize this production in the framework of a biological and renewable process, and at controlled costs. The results of this research have been published in the prestigious scientific journal Nature Communication.
They are both specialists in metabolic engineering and microbial physiology and have just reached an important milestone with their team. Isabelle Meynial-Salles and Philippe Soucaille , teacher-researchers at INSA Toulouse and members of the TBI laboratory, have succeeded in identifying and characterising key enzymes in the metabolism of a bacterium, Clostridium acetobutylicum, and in showing that their involvement is essential for the synthesis of n-butanol. N-butanol is a so-called "fusel" alcohol, which can be used, among other things, as a fuel for unmodified petrol engines or as a base molecule for chemistry.
These results represent an important step: they should make it possible, in the long term, to develop strains that produce only butanol and thus to develop this alcohol by 'a biological and renewable route, with the lowest possible production costs ', says Philippe Soucaille.
Behind it, a large application market
This work, which has received funding from the French National Research Agency (ANR) and the BIOCORE European Project, began about ten years ago. " The fermentation of this bacterium has been widely studied for many years and its physiological characterisation had also shown the presence of activity of these enzymes It has been known for a very long time that an original flow of electrons was necessary to convert sugars into butanol, but it was not known which enzymes were involved in this electron flow "explains Philippe Soucaille. " We have identified these enzymes and characterised the genes coding for these enzymes, which will enable us to create a strain that will produce only butanol as a fermentation product ».
But why aim for butanol production? "Because butanol is a very good bio-fuel which, unlike ethanol, can be mixed with petrol without engine modification "The teacher-researcher replies. " Et le marché potentiel est vaste puisque, outre pouvoir être utilisé comme carburant, le butanol est également utilisé, par exemple, comme solvant ou pour produire des peintures acryliques ". The follow-up that could be given to this work would therefore make it possible to address a dual challenge: " to meet a real demand from the chemical industry for butanol, at a time when the price of barrels of oil is rising, and to offer an alternative to all the chemical routes used to produce these products, which are characterised by their polluting nature ».
Rare teams in France study this bacterium
However, researchers working on this type of bacteria in France are rare. First of all, it is a bacterium that requires the use of specific procedures and materials to carry out the work. The characterisation of proteins and the identification of their genes require the use of classic biochemistry techniques "explains Isabelle Meynial-Salles. " While the purification/characterisation of unknown enzymes was the daily routine of biochemistry laboratories a few years ago, many have since turned to digital genome sequence analysis tools, as this can be faster. But this does not allow us to answer all the questions. We are one of the few in France to continue to exploit this biochemical approach, because it represents heavy work and requires specific equipment, which we have. Indeed, these enzymes have nothing in common with others: they must be isolated, purified and all manipulations must be carried out in oxygen-free media because they are sensitive to oxygen ».
Work to be continued and expanded
But all this is just a step. In addition to working on developing metabolic engineering strategies to develop strains that will enable the production of this butanol, the team also intends to pursue the same type of research to serve the production of diols, organic compounds used, for example, to produce polyesters or de-icing agents for aircraft.
"We really want our basic research to be useful for society."
The two researchers also like to emphasise that their commitment to this work is not only linked to the applicative prospects it offers. " We also do this because we are concerned about the future of society », souligne Isabelle Meynial-Salles. « This is why we have a long-standing commitment to biotechnology for its environmental benefits. We really want our basic research to be useful for society. And not only for its environmental benefit, but also so that it can serve the economy, help create jobs, etc. ».
Article published on the site INSA Toulouse
- Publication references :
- Nature and Communication « Molecular characterization of the missing electron pathways for butanol synthesis in Clostridium acetobutylicum ».
- Foulquier, C., Rivière, A., Heulot, M. et al. Molecular characterization of the missing electron pathways for butanol synthesis in Clostridium acetobutylicum. Nat Commun 13, 4691 (2022). https://doi.org/10.1038/s41467-022-32269-1
