BIOLOGY Volume 2 - A Guide to General Biology - 2004

12. MICROBIOLOGY AND BIOTECHNOLOGY

12.10. Large-scale production

12.10.2. Screening

We know that microorganisms exhibit an immense diversity of Chemical Reactions they can carry out and products they can synthesize. However, only a tiny fraction of this potential is utilized in industrial production. Commercial enterprises, particularly pharmaceutical companies, are in a constant search for microorganisms that could prove useful. In the hope of discovering novel commercially valuable products or more efficient ways of manufacturing existing ones, microorganisms are collected and cultured from all over the world and from the most diverse habitats. Very often, this is a purely empirical endeavor in the sense that chance plays a major role in any discovery. Testing microorganisms in this manner is referred to as screening. A prime example is the ongoing screening carried out to discover new Antibiotics. The first antibiotic was discovered in 1928 by Alexander Fleming and named penicillin after the fungus Penicillium that produces it. Natural antibiotics are chemical substances synthesized by microorganisms that kill other microorganisms or inhibit their growth. Since 1928, over 5,000 different antibiotics have been isolated from microorganisms, including a range of various Penicillins that differ slightly in Structure and activity. Most of the discovered antibiotics are unsuitable for medical use, primarily due to their high toxicity. However, members of the genus Streptomyces have proven to be an exceptionally rich source of diverse antibiotics, including streptomycin.

Antibiotics are used to treat bacterial or Fungal infections in humans and domestic animals. Some of them also inhibit the growth of cancerous tumors. Antibiotics appear to be secondary metabolites (Section 12.5.3). Systematic screening always carries the hope of finding a new "wonder drug" or a microorganism that produces a known antibiotic with enhanced properties.