ABSTRACT
The versatility of fungal biosynthesis is enormous. The use of yeasts dates back to ancient days. Before 7000 B.C., beer was produced in Sumeria. Wine was made in Assyria in 3500 B.C. and ancient Rome had over 250 bakeries which were making leavened bread by 100 B.C. Milk has been made into Kefyr and Koumiss using Kluyveromyces in Asia for many centuries. Today, fungi are producers of five leading fermentation products in terms of tons per year worldwide. These are beer (60 million), wine (30 million), citric acid (900 thousand), single cell protein and fodder yeast (800 thousand), and baker’s yeast (600 thousand). Fungi are also used in many other industrial processes, such as the production of enzymes, vitamins, polysaccharides, polyhydric alcohols, pigments, lipids, and glycolipids. Some of these products are produced commercially while others are potentially valuable in biotechnology. Fungal secondary metabolites are extremely important to our health and nutrition and have tremendous economic impact. The antibiotic market, which includes fungal products (Fig. 1), amounts to almost 30 billion dollars and includes about 160 antibiotics. Other important pharmaceutical secondary metabolites produced by fungi are hypocholesterolemic agents and immunosuppressants, some having markets of over 1 billion dollars per year. In addition to the multiple reaction sequences of fermentations,
Figure 1 The mold Penicillium notatum growing in a flask of culture medium for the production of penicillin in the early days of the antibiotic age. (From Ref. 166.)
fungi are extremely useful in carrying out biotransformation processes. These are becoming essential to the fine chemical industry in the production of single-isomer intermediates. The molecular biotechnology industry has made a major impact in the business world, biopharmaceuticals (recombinant protein drugs, vaccines, and monoclonal antibodies) having a market of 15 billion dollars. Recombinant DNA technology, which includes yeasts and other fungi as hosts, has also produced a revolution in agriculture and has markedly increased markets for microbial enzymes. Molecular manipulations have been added to mutational techniques as means of increasing titers and yields of microbial processes and in discovery of new drugs. Today, fungal biology is a major participant in global industry. The best is yet to come as fungi move into the environmental and energy sectors.
