Trends in microbial synthesis of natural products and biofuels.

Ever since the era of recombinant DNA technology for natural product biosynthesis emerged (292), microorganisms are increasingly becoming common production platforms for many fine chemicals, including natural products and biofuels, that are currently being produced either through chemical methods or using plant and organ cell cultures. The rapid elucidation of biosynthetic pathways made possible through advanced genomic tools has made natural products again the molecules of choice for drug development. Indeed, half of the drugs currently in clinical use are natural products and it is expected that the market size of biotechnology-derived small molecules will exceed billion U.S.$100 in 2010 and billion U.S.$400 in 2030 (3, 293). There are still many challenges facing the use of microorganisms for high-value chemical synthesis. For example, further developments of recent advances are necessary to make a fermentation-based biobutanol industry that can compete effectively with petrochemically derived butanol. As such, we believe that biocatalyst factories such as E. coli and S. cerevisiae will not only continue to be highly attractive alternatives to traditional chemical manufacturing but the application of powerful systems biology approaches will facilitate their expanded role in industrial applications (294-296).