Unique one-pot reaction results in estolides straight from vegetable fatty acids

‘Current processes for the production of esters and estolides come with some considerable disadvantages’, says senior researcher Carmen Boeriu of Wageningen Food & Biobased Research. ‘For these processes high temperatures and aggressive catalysts are used. This will not only result in undesired chemical side effects, but also in high energy consumption and therefore in high process costs and considerable harmful effects on the environment.’

One-pot process

The new process is a ‘one-pot solution’: two enzymes cause three subsequent reactions in one reaction vessel. Another major advantage is that the process takes place at low temperatures in water. Boeriu: ‘We originally wanted to design a process for one-pot transformation to convert vegetable fatty acids into esters or estolides through enzymatic catalysis. At some point, we asked ourselves: “What if we try and start the process one step before, with the vegetable oil as the source of fatty acids?” We have succeeded in doing so. Thank to our invention, we can now produce estolides from vegetable oils in one step and thus need not produce the fatty acids first. Therefore, time-consuming and polluting intermediate steps for separation and treatment are no longer necessary. The solution is not only more effective than current processes for chemical hydroxylation of unsaturated fatty acids, but also the energy costs are considerably less.’

From lubricants to food and cosmetics

The process, which is the result of a joint research project of Wageningen Food & Biobased Research and TU Delft, can be applied to enzymatic catalysis of a wide variety of vegetable fatty acids. Thus, according to Boeriu, a large number of possible bio-based applications will come into the picture: ‘Estolides are organic compounds which are frequently used by the industry as an ingredient for e.g. lubricants, coatings for food and cosmetics and printer ink. We now offer sustainable, bio-degradable alternatives for this.’

The ‘one-pot solution’ has been carefully tested at laboratory scale. Further optimisation and scaling up are the next steps. Boeriu: ‘We would like to take these next steps with partners, from estolide producers to product manufacturers.’