D2.3: Microfluidic assay for detection of glycopolymer synthesizing enzymes

Within RADICALZ, partner INSAT plays a central role by bringing its expertise on polymers and enzymes that allow their tailored production from sugars. These polymers, called polysaccharides or glycopolymers, are a key element of the current and future bioeconomy because they are derived from renewable ressources contrarily to petroleum-based polymers that are are damaging the environment and are made up from non-renewable ressources. However, in order to get these new bio-based polymers fullfil the same roles as the old ones – and there are many – they have to be tailored to fit for each application: for instance, food-based polymers are not the same as those found in laundry products or cosmetics. The next step is to find the appropriate enzymes that will generate each of these tailorized polymers. INSAT has built decades of renowned expertise to find or to engineer enzymes with a focus on those active on sugars, the carbohydrate active enzymes.

Although very efficient, the current methods used for enzyme discovery and engineering are not fast enough to bring the adequate enzymes to industry in a timely manner and therefore at a competitive cost. This is where microfluidics comes into play. This new technology is a game changer for what we are doing at INSAT. A few numbers: One single robust and efficient enzyme is typically found in Nature or through an enzyme engineering strategy for every 100,000 candidates tested. Conventionally, each of these candidates has to be tested individually using robotics and automated methods in which each candidate is assayed in a 100-microlitre mini test tube. Microfluidics on the contrary relies on the miniaturization of the classical test tube to picolitre dimensions (0.000001 microlitre) by means of water-in-oil droplets that are generated in microfluidic devices. In this format, a million candidates can be tested within a single day while it would take few months to perform the same using robots. The price of such a campaign is thus dramatically reduced: machinery and operating costs are typically 100- 1000 times cheaper and the carbon footprint (plasticware, chemicals) is decreased by 99%.

Efforts in RADICALZ (partner INSAT) have focused on the development of new microfluidics tools to screen for glycopolymer-forming enzymes. As an example (figure), it is shown that using an enzyme known for polymer synthesis, it is isolated within a droplet and easily distinguished from other candidates that cannot perform the reaction.