Intensifying the O2-dependent heterogeneous biocatalysis: superoxygenation of solid support from H2O2 by a catalase tailor-made for effective immobilization

Publication date: Available online 29 October 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Juan M. Bolivar, Sabine Schelch, Martin Pfeiffer, Bernd Nidetzky Besides merely destroying H2O2, an important use of the catalase reaction, H2O2 → 1/2 O2 +H2O, is to supply O2 to oxygenation reactions. Due to convenient spatiotemporal control over O2 release, oxygenation from H2O2 is useful in particular for enzymatic reactions confined to solid supports. Because commercial catalases are difficult to immobilize, we have developed a one-step procedure of purification and immobilization of Bordetella pertussis catalase, recombinantly produced in Escherichia coli. Fusion of the catalase to a positively charged binding module enabled effective immobilization of the chimeric enzyme on anionic support (Relisorb SP 400), giving a controllable activity loading of between 5,000 and 100,000 units/g support. Use of the immobilized catalase in combination with H2O2 feeding provided O2 to the reaction of glucose oxidase in solution for a range of volumetric conversion rates (0.2 − 1.5mM/min). Using optical sensing to measure the O2 concentration in the liquid but also in the solid phase, we showed that internal superoxygenation of the support was made possible under these conditions, resulting in an inverted (that is, negative) O2 concentration gradient between the bulk and the particle and allowing the internal O2 concentration to exceed by up to 4-fold the limit of ...

Source: Journal of Molecular Catalysis B: Enzymatic - October 28, 2016 Category: Biochemistry Source Type: research