Submitted to: Yeasts: A Taxonomic Study
Publication Type: Book / Chapter
Publication Acceptance Date: 4/15/1996
Publication Date: N/A
Citation: Interpretive Summary: This review discusses the agricultural and industrial uses of yeasts. Yeasts have long been used for the manufacture of bread, beer and wine. More recently, yeasts are used for the fermentation of fuel alcohol, citric acid and such medically important biochemicals as insulin. A few yeasts are plant pathogens. From the examples given, it is seen that yeasts are quite important for human well-being.
Technical Abstract: For at least 8000 years, yeasts have been an intimate part of bio- technology. The contributions of these simple eukaryotes to the manufacture of beer, wine and bread are well-known. Studies on yeasts were crucial to Pasteur's establishment of fermentation as a life process and to the birth of biochemistry as a result of Buchner's work. Yeasts later became useful for the production of glycerol, enzymes, RNA (for flavor nucleotides), citric acid and single cell protein (for animal feed). They can also be used for the manufacture of ATP, glutathione, polysaccharides and carotenoids. Today yeasts are playing an important role in the conversion of corn to industrial and fuel ethanol; in the future, the substrate could shift to lignocellulosic sources such as municipal, agricultural and industrial wastes. The first vaccine made by recombinant DNA technology (i.e., hepatitis B vaccine) was produced in yeast and successfully marketed. Yeasts have been used to make many recombinant proteins includin human interferon-alpha, human superoxide dismutase, insulin, alpha-1 antitrypsin, bovine prochymosin, mold cellulose, plant thaumatin and tissue plasminogen activator. The ability of yeasts to glycosylate proteins is an advantage over bacterial hosts. Methylotrophic yeasts have emerged as popular organisms for industrial cloning and expression. Recombinant DNA technology has created fermenting yeast strains which are able to hydrolyze barley beta-glucans, starch or unfermentable dextrins, require less maturation time after brewing, or produce less acidity and better-flavored wine. A recombinant baker's yeast has been approved for breadmaking in the UK. It is clear that yeasts will continue to make great contributions to human welfare and quality of life for years to come.