A sustainable alternative to traditional chemical synthesis is the use of enzymes as biocatalysts. Using enzymes, different advantages such as mild reaction conditions and high turnover rates are combined. However, the approach of using soluble enzymes suffers from the fact that enzymes have to be separated from the product post-synthesis and can be inactivated by this process. As enzymes from different host organisms can be combined (enzyme cascades), this offers enormous opportunities for creating advanced metabolic pathways that do not occur in nature.
When enzymes are in close proximity to each other, the generation of by-products is reduced and obstructive effects like product inhibition and unfavorable kinetics can be disabled. This review gives an overview of the current state of the art in the application of enzyme cascades in immobilized forms. Furthermore it focuses on different immobilization techniques for structured immobilizates and the use of enzyme cascade in specially designed (microfluidic) reactor devices.