Ok, it’s not magic but “hard science” – nonetheless, the performance of enzymes in some applications is really breathtaking, especially compared to “conventional” chemical synthesis routes. As research and development advance and ever more processes make it into industrial applications, some trends emerge that might lead the way for the development of the industry.
- Combination is key
Even though enzymes are highly selective and can perform reactions that are hardly accessible to the synthetic chemist, there are also reactions where chemical catalysts are superior. Thus, the combination of chemical and enzymatic steps is the key to efficient synthetic pathways. Researchers are working on reaction cascades in one-pot systems with compartments where different steps are performed successively without cost-intensive intermediary purifications steps. To avoid solvent incompatibilities – enzymatic reactions usually require aqueous systems, organic chemical reactions are run in organic solvents – gel matrices have been successfully employed.
- Unlock nature’s tool kit
While “engineered” enzymes may offer perfect properties, there remain applications e.g. in the food industry calling for naturally-occuring enzymes. Fortunately, nature’s tool kit has an almost unlimited supply of different enzymes – turning the identification into the literal search in the haystack. Modern bioinformatics, a better understanding of metabolic pathways and genome mining methods allow for the screening of tens of thousands of genomes to find the right sequence and, hence, the most appropriate natural enzyme.
- Design your own
Thanks to growing information on the structural biology of proteins, powerful bioinformatics and the integration of databases “tailor-made” enzymes have become more easily accessible. However, designing enzymes and enzymatic systems with desired properties, is still labour-intensive and time-consuming, especially with regard to structural analyses.
- Leash your enzyme to unleash its potential
Currently, cost is a major hurdle for the use of enzymes, especially if they cannot or only at high cost be recovered from the reaction. Immobilisation is the solution to this problem. A number of methods is available, ranging from the adsorption or covalent binding to mostly textile carrier materials or covalent links between the enzyme molecules. Another principle is the encapsulation of enzymes in polymer networks or membranes. However, as the performance of an enzyme depends on its tertiary and quarternary structure, enzyme activity may be influenced negatively by the immobilisation. Other problems include steric factors hindering substrate access to the catalytic center. Thus, experts are still searching for more general immobilization procedures that reduce cost and allow for more or less “standardized” process designs.
- Regard the bigger picture
Even the best enzymatic process is limited by poor reaction technology. Reactor designs that allow for tapping the full potential of the kinetics of enzymatic reactions are still being explored. The challenge lies not least in ensuring maximum mass transfer with minimum shearing of the enzyme-carriers. Thus, the cooperation of biotechnologists, organic chemists and process engineers is crucial to ensure the most efficient – and consequently competitive process.
Do you want to know more? Join the PRAXISforum “Enzymes for Industrial Applications” on 8-9 November 2016 in Frankfurt