Secondary Metabolism and Microbial Physiology

Abstract

This chapter discusses the biochemical similarities and differences between primary and secondary metabolism. The known secondary metabolites are divided into three categories according to the perceived source of the carbon from which their skeletons are derived. These include metabolites derived from acetate, metabolites derived from amino acids, and metabolites derived from components of sugar metabolism. Divisions of secondary metabolites into groups according to the origin of their skeletal carbon atom have many advantages. It allows an impression to be gained of the commitment various taxa have to the use of acetate, amino acids, and sugars as a fuel for secondary metabolism. The chapter concludes that primary metabolism and secondary metabolism are co-extensive. Both processes draw carbon from the same sources and, in many cases, use the same chemical compounds to build that carbon into end products. In several aspects, secondary metabolism is more biochemically sophisticated than primary metabolism. In the areas of polyketide and terpene biosynthesis, there is an inherent biochemical complexity present in secondary metabolism, which is absent from primary metabolism. Problems of considerable logistical involvement arise in secondary metabolism and have been solved satisfactorily.