Title : Development of a solid biocatalyst through the immobilization of laccase enzyme on a chemically modified polylactic acid support
Laccase enzyme is a non-specific oxidoreductase that has great potential in the pharmaceutical, food, chemical and environmental industries. This enzyme, which is mainly produced by lignolytic fungi, catalyses oxidation-reduction reactions of compounds of phenolic basis, among which are a diversity of emerging contaminants of pharmaceutical use. Unfortunately, like other enzymes, its use in its soluble form is limited, by some intrinsic properties of free enzymes, such as high sensitivity to changes in solvent, pH or temperature, low stability, non-reuse, and high cost of production, which makes laccase treatment not viable . Immobilizing laccase has proven to be the most direct way to overcome these problems.
There are numerous methods to immobilize enzymes, however, covalent immobilization on a support is one of the most studied and the one that has achieved the best results in terms of enzyme activity. The supports used must have functional groups that can form covalent bonds with specific amino acid groups of the enzyme without losing activity. In addition, the support must be innocuous to the reaction medium and stable.
One of the materials that has attracted attention is polylactic acid, which is used in 3D printing (also known as additive manufacturing), a fabrication process employing layer-bylayer deposition of materials to produce complex 3D structures with a high flexibility in design and minimal waste of material, which has found applications ranging from the aerospace and construction industry to smart materials, medicine and biotechnology. The problem is that the materials used lack the functional groups required for the interaction between the enzyme and the support. In this area, the chemical modification of printed materials is attracting more and more attention, since, by modifying printed carriers, enzymes can be immobilized on them. Thus, the development of versatile methods for chemical modification has the potential to provide low-cost, efficient enzyme immobilization approaches.
In this study, the immobilization of the enzyme laccase on a chemically modified PLA carrier was evaluated in order to find optimal conditions that allow the maintenance of the catalytic activity of the enzyme. For this, the material was subjected to a process of aminolysis and then activation with glutaraldehyde groups, finally the soluble enzyme was added to the material, causing the covalent bonding between the amino groups of the
enzyme and the glutaraldehyde of the support. To determine the efficiency of the process, the activity of the soluble enzyme in the medium before and after immobilization was measured, as well as the activity of the immobilized biocatalyst, using the ABTS (2,2’-azinobis-(3-etilbenzotiazolin-6-sulfonato)) substrate, through the measurement of the initial rate of hydrolysis in a spectrophotometer, at a suitable temperature and pH.
Audience Take Away:
The audience will learn how to transform a material into a biocatalyst with immobilized enzyme that can be used to catalyze oxidation-reduction reactions using the laccase enzyme, which have application in the elimination of pollutants of phenolic basis, solving problems at industrial and environmental level. With this, other researchers will be able to use this technology to immobilize other enzymes to a support.