Understanding our customers’ industrial processes and establishing enzyme application tests that mimic the application in real life therefore become two of the most important elements of the entire R&D process. But how do you downscale a washing machine, a starch factory, a bakery, or a textile mill to laboratory scale?
Mimicking the real-life conditions of our customers has been a key to Novozymes' success. Today we have a range of tests that reflect our customers’ critical process conditions. We have strong in-house expertise in transforming the full-scale application to a size that is manageable and convenient in the laboratory, ensures high throughput, and has low sample demand. All of these tests correlate to the final application, but in general the correlation gets poorer as the test is downscaled further. We often therefore need a cascade of tests. Each step up in scale shows better correlation, more closely resembles real-life application, and increases the likelihood that a given enzyme will have good technical performance and thus achieve commercial success.
In order to find an enzyme with the properties needed for commercial success we often have to look through thousands (or, in the case of protein-engineered enzymes, even millions) of new enzymes. It is impossible to test all of these enzymes in the final application. Downscaling and simplification is needed to increase the number of tests that can be carried out in a given timeframe.
But how do you simplify the industrial process conditions to a level where they can be transferred to laboratory scale and still reflect the critical real-life problems? This is more difficult than it may seem. How do you know when a given enzyme makes clothes cleaner without washing them in a washing machine? How do you know if the crumb structure of bread will improve without baking real bread? How do you know if an enzyme will reduce the phosphate content of the manure from piglets without feeding trials? How do you know if an enzyme will improve the coloring and wetting properties of a cotton fabric or yarn without trying it out in a textile mill?
The trick is to design the tests in a way that reflects the desired process conditions and simultaneously puts a strong selection pressure on the different enzymes being tested. Only the relevant enzymes should show activity. Preferably we would like to design a test in microtiter plates giving us the full correlation. But most often a cascade of tests is required; starting with relatively simple high-capacity assays and ending up with test systems that are characterized by high correlation with the industrial application but at the same time are much more time-consuming and run at low test capacity.
The first level of testing is carried out in microtiter plates or agar plates. The microorganisms may grow directly on the agar plate or in the microtiter plate, and the secreted enzymes are tested in situ. Poor- and medium-performing enzymes should be deselected as soon as possible, while only the top-performing enzymes should be selected for the next level of evaluation.
The following example is from the detergent area. Small pieces of fabrics soiled with a relevant stain applied in a reproducible way are placed in a microtiter plate. In a robotic screening the enzymes are ranked according to how well they can release the dirt from the fabric in these wells. A real detergent solution is used as in real-life washing. The best enzymes are fermented and purified in an amount sufficient for washing trials at 50–200-ml scale. In this system the mechanical agitation of washing machines can be mimicked, and better correlation to real washing machines is obtained. The final tests with the few best enzymes – before choosing one for upscaling and launch – are performed in full-scale washing machines on regular soiled fabrics.
Novozymes has experienced the conflict between correlation and test capacity for decades, and has built up strong expertise to deal with this challenge. Our know-how within this field is one of the keys to Novozymes’ success.
Novozymes is continually developing and improving its test systems, mimicking existing industrial processes. Sometimes we go one step further and rethink the conventional industrial processes, creating new enzyme-based processes that are superior to those used in the industry today – superior from both an environmental and a cost point of view.