Economic importance of fungi
i) Fungi as food:
The food value of fungi is well known since remote past. Fungi which are used as food include, morels, mushrooms, truffles, fuffballs, and non-woody polypores. About 2000 species of mushroom are known that are edible. Yeast contain a complete protein, consisting of large number of free aminoacids beesides fats, minerals, salts, vitamins, etc. This has resulted in the commercial preparation of yeast cakes. These cakes are used as food. Yeasts are used for making bread. The wheat diastase in the flour converts the starch in the dough to maltose. The maltase from the yeast hydrolyses the maltose to glucose. Zymase ferments the glucose to ethyl alcohol and carbon dioxide. The carbon dioxide raises the dough. The alcohol is driven off during the baking process.
Many fungus metabolites become involved in the fermentation during the processing of foods like 'jalebies', idli, kanji, punjabi warries, toddy, etc. The fungi responsible for these fermentation's are: Saccharomyces bayanus, for jalebies; Torulopsis candida and Trichosporon pillulans, for idli; Hansenula anomala, for kanji; and Saccharomyces cerevisae, for punjabi warries, and toddy.
ii) Industrial uses of Fungi:
Fungi are widely used by man in various kind of industries. Fungus products, produced commercially, include, alcoholic beverages, cheese, organic acids, enzymes, hormones, pigments, vitamins, and alkaloids.
a) Alcohol beverages: Fungi especially yeasts, are used for the production of alcoholic beverages, such as beer, wine, whisky, run and gin. The yeasts ferment glucose to yield ethyl alcohol and carbon dioxide. Ethyl alcohol is used in the production of alcoholic beverages. Carbon dioxide is used in the baking industry for raising the dough. Wines are produced from grapes, or other fruits as a result of fermentation by Saccharomyces ellipsoideus.
b) Cheese Industry: Penicillium roqueforti, and P. camemberti, are used for the production of cheeses.
c) Organic acids: Many fungi are increasingly valuable for the commercial production of various organic acids as their metabolic products examples citric acid, Gallic acid etc.
d) Fungi and enzymes: Various kinds of enzymes are synthesized on commercial scale by using different fungi, e.g, Aspergillus oryzae.
e) Fungi and organic solvents: Yeast is used in the manufacture of many organic solvents such as acetic acid, lactic acid, etc.
f) Fungi and fat production: Certain fungi are good sources of fats. Among them the common are Aspergillus nidulans, A. sydowsi, etc.
g) Fungi and harmones: Gibberellins are the plant hormones that are produced by fungus, Gibberrella fujikuroi. It is used to accelerate growth of several horticultural crops.
h) Fungi and Pigments: Some fungi are grown on commercial basis for the extraction of pigments which are used for the preparation of various dye stuff.
i) Fungi and Vitamins: Many fungus metabolites are the rich sources of vitamins which are used as nutritional supplement, and in medical therapy. example vitamin B produced from yeasts.
j) Fungi and alkaloids: Some fungi produce alkaloids that are used as medicines. The ergots of the fungus Claviceps purpurea contain a number of alkaloids such as ergotamine etc.
iii) Fungi and Medicines
Fungi have explored new field in medicine by producing antibiotics and several other useful components.
a) Antibiotics: Antibiotics are defined as substances of biological origin which, at low concentrations, can inhibit the growth of bacteria and other microorganisms. In 1919, sir Alexander Flaming, for the first time, discovered the antibiotic named penicillin from the fungal colony of penicillium notatum. Since then, great many compounds with antibiotic actions have been isolated.
b) Ergot: Ergot is the sclerotium of the Claviceps purpurea, which infects rye, and less commonly other grains. Ergot contains several alkaloids which are more extensively used to control postpartum haemorrage.
c) Ephedrine: Ephedrine is extracted by yeast from benzaldehyde. Yeast converts benzaldehyde into L-acetylphenyl-carbinol which by amination is converted into L-ephedrine. Ephedrine is used in Asthma disease.
iv) Fungi and soil fertility: In the dead bodies of the animals and in the exertions of animals, there are large quantities of carbon, nitrogen, and other essential elements, which are not available for the use of green plants. The fungi and various bacteria decompose the organic compounds of dead plants and animals and excretions of animals and convert the essential elements into forms in which they can be used again as raw material by plants. The fungi also prevent many inorganic substances from being lost by leaching action.
v) Fungi as Mycorrhizal association: A dual association of a root of higher plant and a fungus that is not disease producing is referred to as mycorriza. A great many free living soil fungi are capable of forming mycorrizas. Recent studies have revealed that mycorrizal fungi are often beneficial to their plant partners. Mycorrhizas enhance mineral absorption by the green plants