The versatility of microbial biosynthesis is enormous. The most industrially important primary me- tabolites are the amino acids, nucleotides, vitamins, solvents, and organic acids. Millions of tons of amino acids are produced each year with a total multibillion dollar market. Many synthetic vitamin production processes are being replaced by microbial fermentations. In addition to the multiple reac- tion sequences of fermentations, microorganisms are extremely useful in carrying out biotransforma- tion processes. These are becoming essential to the fine chemical industry in the production of single- isomer intermediates. Microbially produced secondary metabolites are extremely important to our health and nutrition. As a group, they have tremendous economic importance. The antibiotic market amounts to almost 30 billion dollars and includes about 160 antibiotics and derivatives such as the