Every cell has a silver lining! The toxicity of Ag nanoparticles is investigated using a panel of recombinant bioluminescent bacteria. The presence of the nanoparticles leads to the production of a superoxide radical (see figure). Furthermore, the Ag nanoparticles damage the cellular membranes, causing a disruption in the ion efflux system. Thus, the cells cannot effectively extrude the Ag ions and, hence, Ag nanoparticles cause more damage than do Ag ions.

Multienzymatic cascade reactions are a most important technology to succeed in industrial process development, such as synthesis of pharmaceutical, cosmetic, and nutritional compounds. Different strategies to construct multienzyme structures have been widely reported. Enzymes complexes are designed by three types of routes: (i) fusion proteins, (ii) enzyme scaffolds, or (iii) immobilization. As a result, enzyme complexes can enhance cascade enzymatic activity through substrate channeling. In particular, recent advances in materials science have led to syntheses of various materials applicable for enzyme immobilization. This review discusses different cases for assembling multienzyme complexes via random co-immobilization, compartmentalization, and positional co-immobilization. The advantages of using immobilized multienzymes include not only improved cascade enzymatic activity via substrate channeling but also enhanced enzyme stability and ease of recovery for reuse. In this review, we also consider the latest studies of different model enzyme reactions immobilized on various support materials, as multienzyme systems allow for economical product synthesis through bioprocesses.

Immobilization is a key technology for successful realization of enzyme‐based industrial processes, particularly for production of green and sustainable energy or chemicals from biomass‐derived catalytic conversion. Different methods to immobilize enzymes are critically reviewed. In principle, enzymes are immobilized via three major routes (i) binding to a support, (ii) encapsulation or entrapment, or (iii) cross‐linking (carrier free). As a result, immobilizing enzymes on certain supports can enhance storage and operational stability. In addition, recent breakthroughs in nano and hybrid technology have made various materials more affordable hosts for enzyme immobilization. This review discusses different approaches to improve enzyme stability in various materials such as nanoparticles, nanofibers, mesoporous materials, sol–gel silica, and alginate‐based microspheres. The advantages of stabilized enzyme systems are from its simple separation and ease recovery for reuse, while maintaining activity and selectivity. This review also considers the latest studies conducted on different enzymes immobilized on various support materials with immense potential for biosensor, antibiotic production, food industry, biodiesel production, and bioremediation, because stabilized enzyme systems are expected to be environmental friendly, inexpensive, and easy to use for enzyme‐based industrial applications.

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