Enzymatic catalysis from lab scale to industrial demonstration scale
The largest European oleochemical producer, Oleon, is looking into what enzymes can mean for oleochemistry from an industrial point of view and built a pilot reactor for this purpose at its production site in Oelegem.
Figure 1: Enzymatic pilot reactor in Oelegem as seen from the control room
“Optimize processes to increase sustainability”
“Over these last years we systematically increased the share of renewable raw materials used in our products. In the development of new solutions for our customers, our first reflex has become to start from non-petrochemical products. Additionally, regarding our existing product range, our purchase team is constantly on the lookout for greener alternatives for our current raw materials. Further, in our plants we monitor our energy consumption and our waste streams and set ambitious goals each year to continuously improve the environmental footprint of our products. Optimizations in processes can impact the sustainability of a product to a great extent, however in comparison to a raw material change, they imply more innovative and in-depth research, and often involve important investments and a change in the way of working. Therefore, they are less often undertaken.”
Oleon has successfully taken up this challenge to innovate its processes in the past. Some notable examples are the development of a process to make monopropylene glycol ex renewable feed stock and more recently the patented novel way to produce isostearic acid with improved stability properties from rapeseed.
Using enzymes as catalysts
Today Oleon is looking into what enzymes can mean for oleochemistry from an industrial point of view. It is a fact that the synthesis of esters and structured triglycerides using enzymes as catalysts is not new. Literature dating back several decades discusses the type of enzymes that can be employed and process parameters leading to acceptable yields. Nevertheless, apart from some isolated pilot and industrial efforts, enzymatic catalysis has not yet broken through in the oleochemical industry. Main reasons for this are that this way of working requires a different industrial setup, and accompanying investments, and the fact that enzymes are both expensive in purchase and sensitive to deactivation if not treated correctly, which entails a certain risk. These rather ‘practical’ issues are not discussed in scientific literature. In order to better understand these processes and judge the feasibility, Oleon embarked on a journey together with the VITO research institute to bring enzymatic catalysis to industrial scale at Oleon.
LipaMetics: from lab to pilot scale
The LipaMetics project was a CATALISTI/VLAIO funded research project that finished about two years ago with partners Oleon, VITO, GOVA and Nuscience. It aimed to devise an industrial feasible protocol to make isopropyl palmitate on laboratory scale at VITO and afterwards test this on 150 kg pilot scale at Oleon as a proof of concept (see Figure 1). Although some good initial indications existed in literature, a number of questions needed to be answered: which enzyme can be used and also reused for multiple batches in order to render the project economically feasible? Would a batch or continuous approach be the most suited? Which process conditions for the reaction, but also for the washing and storage of enzymes are most suited to protect the enzymes while still assuring a high quality product?
Those and many other questions were studied in the project and, towards the end, samples of isopropyl palmitate in specifications were obtained and validated at both Oleon and GOVA and Nuscience for their acceptability in the market.
Figure 3: Conversion of palmitic acid to isopropyl palmitate in function of time
Following the feasibility study of this technology, Oleon took a closer look at the viability of a follow-up research project.
From an economic point of view, this project makes sense: a big cost of producing isopropyl esters is the loss of isopropanol in the classical process due to its high volatility at elevated temperature. Furthermore, being a solvent for cosmetic industry color and odor are important aspects to consider and which are often more difficult to manage at chemical esterification temperatures. Therefore, often post-treatments are needed which both incur extra costs and yield loss and which cannot even remove all unwanted side products. As can be seen from Figure 2, a comparison in odor profile and intensity of two samples of isopropyl palmitate starting from the same raw materials but produced in the enzymatic (no post-treatment) and chemical (including post-treatment), shows clearly the advantage of the enzymatic way of producing. More than just a way to reduce post-treatment, it shows that enzymatic process can result in products with superior quality on the market which offer a competitive advantage.