Directed evolution of enzymes and biosynthetic pathways.

Directed evolution is an important tool for overcoming the limitations of natural enzymes as biocatalysts. Recent advances have focused on applying directed evolution to a variety of enzymes, such as epoxide hydrolase, glyphosate N-acetyltransferase, xylanase and phosphotriesterase, in order to improve their activity, selectivity, stability and solubility. The focus has also shifted to manipulating biosynthetic pathways for the production of many naturally synthesized compounds, as well as the production of novel 'unnatural' compounds. A combined directed evolution and computational design approach is becoming increasingly important in exploring enzyme sequence-space and creating improved or novel enzymes. Fueled by recent breakthroughs in genomics and metagenomics, these developments should help expand the use of biocatalysts in industry.