A. Harmful economic aspects of fungi, i.e. negative aspects of fungi :
Spoilage of food, stored grains and other essential commodities: Fungi (mould fungi) are the chief agents responsible for most of the disintegration of fruits, vegetables and other done stuffs, e.g. jams, jelly, pickles, bread, various cooked-foods eat. if not properly stored. Common food damaging fungi are Aspergillus, Penicillium, Mucor and Rhizopus.
Induce diseases of animals and human being: Fungi are responsible for the diseases of animals as well as human beings. Some of the serious diseases of human being, i.e. the diseases of skin, far, throat, nose and as well as bronchial and intestinal disorders are caused by various groups of fungi. A few species of Mucor and Rhizopus are common fungi infecting lungs, brain and gastric system, Neurospora and Fusarium infect corneal tissue of eye. Histoplasma infects lungs, spleen, lives, kidney and also lymphatic system.
Some deuteromycetous and ascomycetous fungi contaminate the stored harvested grains- the infected grains of wheat, maize etc. my contain spores and fungal hyphae beneath the outer layers. When such contaminated seeds and grains are consumed by animals and human being, they cause serious diseases including liver cancer. Besides infecting foods and grains, Aspergillus, Penicillium are also responsible for the destruction of fabrics, leather, paper, optical and electrical and other consumer's goods that are subject to fungal attack.
Several species of Aspergillus are human pathogens, causing a group of diseases collectively called Aspergilloses. Aspergillus infects nasal tissues and lungs. Candida albicans is the cause of many diseases in man. Skin candidiasis, broncho candidiasis, oral candidiasis, vulvo-vaginal candidiasis, palm, ovary candidiasis etc. are the examples of different types of candidiasis of human. Species of Cercospora, Cryptococcus and others infest animal and human bodies causing thereby a disease known as mycosis.
Above mentioned diseases can be controlled by effective bothetnick compounds e.g. Amphotericin- B and Griseofulvin.
Trichophyton and Microsporum are the two species that are most prevalent fungi causing the diseases (aspergillosis), candidiasis, phycomycosis, and mycotic abortions in large number of animals in India. Ring worm of dogs and horses is caused by Microsporum canis. Aspergillus fumigatus cause cattle bovine abortion in many chickens, ducks and other birds. Mycotic abortions of cattle is very common disease. Saprolegnia and Achlya are fungi parasites of dishes.
Induce diseases of plants: Fungi are also responsible for millions of rupees worth of damage to crops by causing plast diseases. Of the serious diseases of crop plants, 'damping off' diseases of potato plant caused by Phythium debaryanum; 'late blight' or 'rot' diseases of potato plant caused by Phytophthora infestans; 'downy mildew' diseases of crucifers caused by Peronospora parasitica etc. may be mentioned. The various members of polypores among Basidiomycotina are responsible in causing serious diseases and damages of timber and lumber yielding plants, railway sleepers, wooden pillars, furniture etc. The members of 'rust' (Puccinia) and 'smut' (Ustilago, Tilletia, etc.) are also highly destructive to various different crop plants like wheat, maize, oct, barley etc. Many fungi cause immense lord to timber and lumber wei trees by causing wood-rot disease. Claviceps purpurea (Ascomycotina) causes the 'ergot' disease of rye.
Toxic substances obtained from fungi: Several toxins have been extracted from mushroom like Amantia phalloides. There toxins fall mainly in two groups such as phallotoxins and amatoxins. The extensively studied phallotoxin is phalloidin and amatoxin is alfa-amanitin. Both the toxins affect lives, stomach and intestine cells in the later stage. Phalloidin and alfa-amanitin poisoning can be treated by cytochrome-C and thioctic acid.
The sclerotia of Claviceps purpureacontain many poisonous alkaloids such as ergotamine, ergometrine, ergo-crystinine, ergocristina and ergonovin. Symptoms of ergot poisoning in man are diarrhoea, abdominal pain, vomiting etc. The animals that feed on such sclerotia may even abort; their legs, hoofs, tail etc. may become gangrenous.
Aspergillus flavous and Aspergillus niger may infest dried foods and ground out meal and produce a dangerous toxins called aflatoxin-- this toxin has carginogenic effect.
Wood-rotting fungi:Many wood rotting fungi e.g. a few species of Lentinus, Serpula lacrymans, Coniophora cerebella, etc. cause a great monetary loss. Dry rot and wet rot are most dangerous diseases of the timber.
Fungi growing in Aircraft fuel tanks: Amorphotheca resinae is the main dungbl organism of the kerosene-based fuel tanks of aircrafts. This fungus grows in storage and fuel tanks profusely as a result fungal hyphae may plug the valves and pipes of the aircraft and cause disastrous effect during flight.
B. Beneficial economic aspects of fungi :
Besides so many harmful i.e. destructive effects, fungi also beneficial to agricultural and industrial fields.
To maintain the soil fertility:Many saprophytic fungi along with bacteria decompose the dead organic matters and thereby hey help in returning the nutrients (derived from the organic matters) to the soil in a form available to green plants. There fungi also prevent many inorganic substances from being lost by leaching action. The large amount of Carbon-di-oxide liberated by fungi during decomposition of organic matter is also used by green plants for the synthesis of their food.
In the production of enzymes, vitamins and hormones:Amylase, a well known enzyme is produced from Aspergillus niger and Aspergillus oryzae. Digestin, diastase, ployzime etc. are obtained from Aspergillus flavus. For the enzyme invertase, Saccharomyces cerevisiae is used. All the yeasts including Saccharomyces cerevisiae are source of vitamin B-complex and riboflavin. The fungus Gibberella fujikuroi is the source of a group of plant hormones used to accelerate the growth of many crops. The fungi from the most important basis of industrial processes involving fermentation such as the making of winds, beers, breads and the prepartino of cheeses (from various type of yeasts and few Penicillium sp.)
In the production of antibiotic substances, alkaloids and organic acids:Most of the fungi produce enzymes, alkaloids and various other organic compounds as their metabolic products; there metabolic products are of great economic importance. One of the important metabolic products produced by fungi is the antibiotics. There antibiotics either destroy or inhibit the growth of bacteria and muses micro-organisms-- hence antibiotics produces by various fungi are used in the manufacture of drugs and also for other various purposes. In 1929 Sir Alexander Fleming for the first time established the fact that certain fungi could produce antibiotics. The most wonder drug 'penicillin' is an antibiotic substance extracted from Penicillium notatum. Later on Raper (1952) extracted penicillin from Penicillium chrysogenum. Griseofulvin, one of the best known antibiotic against fungal diseases of skin is obtainted from Penicillium griseofulvum. Another importent antibiotic 'chaetomin' is extracted from Chaetomin cochliodes. Many other antifungal and antibacterial antibiotics produced by Armillariella mellea in culture - this antibiotics are effective against Gram positive bacteria and against some soil fungi such as Trichoderma.
The various types of alkaloids obtained from fungi are also used as medicine. The sclerotia i.e., the so-called 'ergots' of the fungus Claviceps purpurea contain a number of alkaloids which are used for stops haemorrhage after child birth.
A few organic acids are also produced from fungi. Citric acid and gluconic acids are produced from Aspergillus niger. Rhizopus stolonifer is used for the preparation of lactic acid and fumaric acid.
Fungi used as food: Some fungi e.g. 'mushrooms' (Agaricus campestris, A. bisporus, Volvariella volvacea, Pleurotus sajar-caju, etc.), 'morels' (Morchella esculenta) etc. are used as human food. Some species under the lentr Tuber are commonly called 'truffles' - there truffles are used largely as food. Truffles are also recognised for their good flavour. In Italy and France Truffles are canned export. Agaricus bisporus, species of Volvariella, Pleurotus, etc. are widely cultivated at the low cost of production, there fungi from one of the most relishable dishes and sold in the market as fresh mushrooms or canned and made into soup, sauces and other food products. Fractifications of some fungi, e.g, 'puff ball' (Lycoperdon sp.) are also edible when young. Well known yeast cake is obtained from Saccharomyces cerevisiae - yeast protein is called commonly 'single cell protein', and its protein is above 40% ; yeast cake is produced from Saccharomyces cerevisiae. A popular food known as 'sufu' is produced from Mucor, Antimucor, etc. (Lockwood, 1975).
Useful for academic studies: Besides the above mentioned cannonic importance of fungi, fungi are also important from the view point of academical studies. Fungi are on longer the only concern of Mycologists. Genetics, Cytologists and Biochemists have found that fungi may be important research tools in the study of biological processes. Cytological and genetical studies were made first on the fungus Neurospora. For the study of the laws of heredity Neurospora is being used since 192s. Dodge, an American Mycologist, through a series of experiments on Neurospora has shown foundation of a new branch of science which is also known to be as garloge genetics. Rusch (1968) has shown that Physarum polycephalum (a slime mould) is a good specimen for the study of DNA synthesis, morphogenesis, mitotic cycle and other processes also.
In biological control of soil-borne pathogens and insects: Some fungi (Arthobotrys musiformis, Dactylaria thaumasia, etc.) are known are predaceous fungi, because they parasitise amoebae, nematodes etc. - such fungi are used in large scale for controlling soil borne pathogens, reagak nematodes. Predaceous fungi possess a special sticky net works or sticky knobs for trapping and destroying such pathogens.
Mycorrhizal association: Beneficial relationship (symbiotic) between the hyphae of soil-borne fungi and the roots of higher plants is called Mycorrhiza. Most of the deciduous or evergreen trees have ectomycorrhizas - in this case the roots are externally surrounded by the hyphae of some fungi as Boletus, Phallus, Scleroderma, Amantia, Tricholoma, etc. Those fungi decomposes soil organic matter and the leaf litter. Ectomycorrhiza promotes the growth of the used-seedlings. Dungbl hyphae easily absorb nutrients like phosphorous, calcium, nitrogen, potassium etc. and then passed to the tissues of roots. In this way a symbiotic relationship is established.
These are the common economic importance in both positive and negative way. Yeasts are used in bakery products in huge amounts.