Do you know that our day to day activities are made in such a way that it intervolve with that of micro and macro organisms which can either be beneficial or detrimental to man. For the purpose of this write up I will be focusing more on micro-organisms using fungi as a case study, other examples of micro-organism are algae, bacteria, viruses, protozoa.
The study of micro-organism is called micro-biology, which is the study of very small living organisms that can be seen with the aid of a microscope. Micro-organisms are ubiquitous in nature because they can be found everywhere.
According to lucy kavaler-culled from prescott et al: yeast, moulds, mushrooms, mildews other fungi pervade our world. They work great good and terrible evil. Upon them, indeed hangs the balance of life without their presence in the life circle of decay and regeneration neither man nor any other living thing could survive.
The science and study of fungi (sing fungus) as biological entities is called mycology. Scientists who study fungi are called mycologists. Fungi have a diversity of morphological appearances depending on the species. We are all familiar with the gross appearance of many multicellular fungi, examples are
- The velvety blue and green growth on rotting oranges.
- The black growth on rotting tomatoes.
- The whitish gray out growth on bread and
- The mushrooms in the fields.
http://www.fichasmicologicas.com/?micos=1&alf=*&art=29
Fungi comprises of the moulds and yeast. Moulds are filamentous and multicellular, yeasts are usually unicellular.
Fungi are eukaryotic, spurring-bearing protist that lacks chlorophyll. They generally reproduce both sexually and asexually. They have somatic structures which are surrounded by cell walls consisting of polysaccharides cellulose and /or chitin, mannan, glucan.
N/B fungi are heterotrophic organisms, they require organic compounds for nutrition
- When they feed on dead organic matter, they are known as saprophytes
- When living in another organism they are known as parasites
IMPORTANCE OF FUNGI AS OUR FRREIND
There are over approximately 50,000 species of fungi, most of which are beneficial to mankind, eg
Saprophytes decomposes complex plant and animal remains breaking
them down into smaller chemical substances that are returned to the soil. This is called biodegradation.Food Industry:
(i) The brewing of beer, making of wine and bread making (leavening of dough) saccharomyces crevisiae or closely relate species
(ii) In the ripening of some cheeses e.g blue cheeses produced by inoculating penicillium Roquefort into the veins of the cheese. Various soft cheeses like camembert chease are produced by inoculation cheese penicillium camemberti.
(iii) Saprophytic fungi are also used to produce soya sauce and to ferment many staple food.
(iv) Single cell protein(scp)-with technological developments, there is increasing interest in production of single cell protein[scp] from fungi either as food for man or as animal feed e.g. Candida, saccharomyces, hensenula, kluyveromyces are grown as single cell protein using the following substrates: sulphite liquor (from wood industry , whey, paraffin, methanol and ethanol)
(v) Fungi (e.g mushroom) are also used as food.Chemical activities
(i) Citric acid production for soft drinks etc is based on growth of Aspergillus niger on sugar
(ii) The production of antibiotic such as penicillium natatum was first discovered by flaming to produce penicillin.
(iii) Gibberellins (plant hormones) are another group of secondary metabolites produced commercially from fungi for the horticultural industry.
(iv) More recently, yeasts have been genetically engineered to produced human insulin and growth hormone ‘somatostatin’.
FUNGI AS OUR ENEMY
(i) They cause biodeterioration e.g. they decompose timber, rot wood leather, and textiles.
(ii) Cause food spoilage. Some food spoilage fungi produce potent mycotoxins e.g. aflatoxin which render food unusable and is said to cause liver cancer.
(iii) As parasites fungi causes diseases in plants, humans and animals eg dermatophytes[ringworm], mycoses 
(iv) They grow in aviation kerosene and this activity cause corrosion of the aluminum walls of aircraft fuel tanks (eg. Amorphotheca resinae)
(v) They grow on bathroom and kitchen walls and art treasures.
Therefore base on the above facts we can say that fungi is our friend and as well our enemy.
