A novel enzymatic catalyst for biodiesel production

Jul 04, 2011
Diagram showing the enzyme biocatalytic reactor and its unidirectional continuous flow operation that uses enzymatic catalysis to turn triesters into biodiesel. © CNRS

Continuous production of biodiesel can now be envisaged thanks to a novel catalyst developed by a French team at CNRS's Centre de Recherches Paul Pascal (CRPP). The results, which have been patented, have just been published in the journal Energy & Environmental Science.

Biofuel production provides an alternative to fossil fuels. Biodiesels, for instance, are processed products based on oils from oleaginous plants such as oilseed rape, palm, sunflower and soybeans. They result from a chemical reaction, catalyzed in either an acidic or preferably a basic medium, between a vegetable oil (90%) and an alcohol (10%). This reaction, known as transesterification, converts the mixture into a methyl ester (the main constituent of biodiesel) and glycerol. A saponification side reaction (methyl ester conversion into the corresponding acid salt) reduces methyl ester yield. To increase the yield, it was therefore necessary to develop alternative catalysts.

For this type of reaction, certain enzymatic catalysts such as those belonging to the family of lipases (triglyceride hydrolases) are particularly efficient and selective. However, their high cost and low conformational stability restrict their industrial use, unless they can be irreversibly confined in porous matrices, allowing good accessibility and enhanced mass transport. This has now been achieved by the team led by Professor Renal Backov.

In an initial study, they had already demonstrated the possibility of efficient catalysis, by developing modified silica-based cellular matrices that make it possible to confine lipases in order to obtain exceptional yields for hydrolysis, esterification and transesterification reactions. Their work had also shown that unpurified enzymes could be used in the matrices. The fact that they were unpurified was a first step to significantly reducing the cost of biocatalysts. However, the methodology did not allow continuous production. This obstacle has now been overcome.

Researchers have developed a new method that generates the cellular hybrid biocatalyst in situ inside a chromotography column. This novel approach makes it possible to carry out continuous, unidirectional flow synthesis over long periods, since catalytic activity and ethyl ester production are maintained at high, practically steady levels during a two-month period of time. These results are amongst the best ever obtained in this field.

Research is continuing into solvent-free conversion of triesters, aimed at minimizing waste production and curbing the use of solvents and metals in chemical transformation processes. This work, which meets current energy and environmental requirements, shows how much chemists are working in the public interest, and confirms the importance of integrative chemistry.

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More information: References:

-- “Enzyme-Based Biohybrid Foams Designed for Continuous Flow Heterogeneous Catalysis and Biodiesel Production”, N.Brun, A.Babeau-Garcia, M.-F.Achard, C.Sanchez, F.Durand, L.Guillaume, M.Birot, H.Deleuze and R.Backov - Energy & Environmental Science, 2011 DOI:10.1039/C1EE01295A

-- Catalyseur enzymatique hétérogène, procédé de préparation et utilisation pour la catalyse enzymatique en flux continu. N.Brun, H.Deleuze, C.Sanchez and R.Backov. French patent 2010. File number FR10-56099.

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User comments : 7

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gmurphy
not rated yet Jul 04, 2011
I know this is offtopic but the "rape" in oilseed rape comes from the latin word "rapum", meaning turnip. http://en.wikiped...History, thank you wikipedia :)
Trim
4 / 5 (1) Jul 04, 2011
So unlike the Vikings the Romans only turniped and pillaged?
aroc91
5 / 5 (1) Jul 04, 2011
I know this is offtopic but the "rape" in oilseed rape comes from the latin word "rapum", meaning turnip. http://en.wikiped...History, thank you wikipedia :)


I'm pretty sure you mean rapeseed oil.
Telekinetic
1 / 5 (2) Jul 04, 2011
Now the whole world will smell like french fries.
stripeless_zebra
not rated yet Jul 04, 2011
As always it works great in a lab but won't be commercialized.
In the meantime our civilization is already past the Peak Oil and waiting for the energy disaster to happen. Cheap mass production of biofuels is decades away if ever possible.
Sebas
not rated yet Jul 04, 2011
There are millions of inventions that won't be commercialized. That's not because there are evil oil corporations that are hindering it; It's all about economics. If this can be scaled up and compete with the oil industry, of course it will be commercialized (and if it's a profitable idea then why shouldn't for example an oil company invest in it?)

I just read the article and it's quite awesome that they could covalently immobilize the enzymes onto a porous membrane and still keep a quite high yield. But the problem is that after 2 months the yield drops to about 50% and this is still quite an issue if it would like to compete and have any impact in the huge diesel market.
Although this may be difficult to scale up (because you would need enormous amounts of enzymes which would need enormous amounts of micro-organisms), it might find its way to private homes or companies who produce vegetable oils.
stripeless_zebra
not rated yet Jul 04, 2011
... it might find its way to private homes or companies who produce vegetable oils.


...and that's what Mr. Obama calls "The end to oil dependency" :)

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