Enzyme engineering in the context of novel pathways and products.

In recent years, enzyme engineering was used to fine-tune a diverse set of proteins to realize new biosynthetic pathways and gain access to novel products. However, enzymes in nature do not always meet the required demands in terms of activity, selectivity and stability. In these cases enzyme engineering has been used to improve the enzyme properties, which facilitated the development of tailor-made functional biocatalysts, even beyond their natural capabilities. Examples can be found in the three main areas of chemical biotechnology: single-step biocatalysis, metabolic engineering and enzymatic cascades. In this review we highlight recently published work in all of these three fields and emphasize the main trends and differences.