Pseudomonas Introduction

The discovery of the antibiotic penicillin by Alexander Fleming in 1928 eventually led to the formal treatment of disease with such microbial derived drugs (Wong, 2003). Penicillin is a natural product, and scientists have continued to search natural sources for new and effective medicinal compounds. Today almost half of the drugs used to treat disease have their roots in natural products (Dewick, 2002). Nevertheless, some pathogens still go untreated and others have developed resistance to known remedies, creating a constant need for new treatment methods. As the demand for novel remedies continues, natural products are still an important source of new medicines. Natural products, sometimes known as secondary metabolites, are defined as compounds that do not appear to be essential to the life of the producing organism, but which may serve some other defensive, or anti-predatory role (Malik, 1980; DeLisa, 2002). Often these secondary metabolites are found to be organism specific and vary structurally under different growth conditions. In most cases, the biosynthetic building blocks for these secondary metabolites are derived from primary metabolites such as organic acids, amino acids, and carbohydrates leading to a wide range of structures. In microbes, secondary metabolite production is most often suppressed during the lag and exponential phases of growth and is greatest during the stationary phase when the highest concentration of primary metabolism side products is present (Malik, 1980). Based on their biosynthetic origin, secondary metabolites are classified into five main classes of natural products: polyketides, terpenes, shikimates, peptides, and