In-flow protein immobilization monitored by magnetic resonance imaging

Selective Coimmobilization of His-Tagged Enzymes on Yttrium-Stabilized Zirconia-Based Membranes for Continuous Asymmetric Bioreductions

Scalability, process control, and modularity are some of the advantages that make flow biocatalysis a key-enabling technology for green and sustainable chemistry. In this context, rigid porous solid membranes hold the promise to expand the toolbox of flow biocatalysis due to their chemical stability and inertness. Yttrium-stabilized zirconia (YSZ) fulfills these properties; however, it has been scarcely exploited as a carrier for enzymes. Here, we discovered an unprecedented interaction between YSZ materials and His-tagged enzymes that enables the fabrication of multifunctional biocatalytic membranes for bioredox cascades. X-ray photoelectron spectroscopy suggests that enzyme immobilization is driven by coordination interactions between the imidazole groups of His-tags and both Zr and Y atoms. As model enzymes, we coimmobilized in-flow a thermophilic hydroxybutyryl-CoA dehydrogenase (TtHBDH-His) and a formate dehydrogenase (His-CbFDH) for the continuous asymmetric reduction of ethyl acetoacetate with in situ redox cofactor recycling. Fluorescence confocal microscopy deciphered the spatial organization of the two coimmobilized enzymes, pointing out the importance of the coimmobilization sequence. Finally, the coimmobilized system succeeded in situ, recycling the redox cofactor, maintaining the specific productivity using only 0.05 mM NADH, and accumulating a total enzyme turnover number of 4000 in 24 h. This work presents YSZ materials as ready-to-use carriers for the site-directed enzyme in-flow immobilization and the application of the resulting heterogeneous biocatalysts for continuous biomanufacturing.

Visualization of materials using the confocal laser scanning microscopy technique

The development of materials science always benefits from advanced characterizations. Currently, imaging techniques are of great technological importance in both fundamental and applied research on materials. In comparison to conventional visualization methods, confocal laser scanning microscopy (CLSM) is non-invasive, with macroscale and high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in a material. Therefore, the CLSM-based visualization technique could provide direct and model-independent insight into material characterizations. This review summarizes the recent applications of CLSM in materials science. The current CLSM approaches for the visualization of surface structures, internal structures, spatial structures and reaction processes are discussed in detail. Finally, we provide our thoughts and predictions on the future development of CLSM in materials science. The purpose of this review is to guide researchers to build a suitable CLSM approach for material characterizations, and to open viable opportunities and inspirations for the development of new strategies aiming at the preparation of advanced materials. We hope that this review will be useful for a wide range of research communities of materials science, chemistry, and engineering.

The rise of continuous flow biocatalysis – fundamentals, very recent developments and future perspectives

Very recent developments in the field of biocatalysis in continuously operated systems. Special attention on the future perspectives in this key emerging technological area ranging from process analytical technologies to digitalization.