Process development and metabolic engineering for the overproduction of natural and unnatural polyketides.

Polyketide natural products are a rich source of bioactive substances that have found considerable use in human health and agriculture. Their complex structures require that they be produced via fermentation processes. This review describes the strategies and challenges used to develop practical fermentation strains and processes for polyketide production. Classical strain improvement procedures, process development methods, and metabolic engineering approaches are described. The elucidation of molecular mechanisms that underlie polyketide biosynthesis has played an important role in each of these areas over the past few years.