Microbes and their uses

Introduction :

Microbes are present everywhere on earch, iie. in soil, air,

water, inside our body and that of other animals and plants.

Ihey are even present in extreme conditions like thermal

vents (geysers) with high temperature as 100°C, under thick

layers of snow and in highly acidic environments. The

microbes like fungi and bacteria can be cultured in laboratory on nutritive media to form colonies, that can be seen with the naked eyes. Such cultures are useful in scientific studies on microorganisms. Microbes have also become part of many useful articles used by humans like fermented honey, wines,bread, curd, etc. The various microbes used in household products, industries and sewage are discussed further.

Microbes in Household Products :

⇒Microbes and their products are used in everyday life,

  e.g. production of curd, formation of dough,cheese,etc...

Curd :

⇒Microorganisms like Lacobacillus and other commonly called Lactic Acid Bacteria (LAB) grow in milk and convert it into curd. We have seen at home that a starter is added to milk which turn it into curd.

⇒ This starter is known as inoculum, which contain millions of LAB. During growth, LAB produce acids that coagulate and partially digest the milk proteins. 

⇒Thus, converting milk to curd. They also improve nutritional quality by increasing vitamin-B, content of the curd.

 ⇒A number of organic acids can also be found in curd. LAB also play very beneficial role in checking disease causing microbes in stomach.

Dough :

⇒Microbes are used in making foods such as dosa and idli.The puffed up appearance of their dough is due to the production of CO, gas through fermentation by bacteria.

⇒In bread making, dough is fermented using baker's yeast(Saccharomyces cerevisiae).

Toddy :

⇒It is a traditional drink of some parts of Southern India.It is made by fermenting sap from palmn trees, coconut, etc.

⇒Microbes are also used to ferment fish, soybean, bamboo,shoots, etc. to make food.

Cheese :

⇒It is one of the oldest food item in which microbes were used. It is formed by partial degradation of milk by different microorganisms.

⇒Swiss cheese : Propionibacterium shermanni

⇒Roquefort cheese: Penicillium roquefortii

Fermented beverages :

⇒Microbes especially yeasts have been used from time immemorial for the production of beverages like wine, beer,whisky, brandy and rum. For this purpose, the same yeat

Saccharomyces cerevisiae used for bread making and commonly called brewer's yeast, is used for fermenting.

⇒Depending upon the type of raw material and processing,different types of alcoholic drinks are prepared. 

⇒Wine and beer are filtered, pasteurised and bottled without distillation.whereas whisky, brandy and rum are produced by distillation

(to increase the alcoholic content) of fermented broth. 

Antibiotics :

⇒The term 'antibiotics' was coined by Waksman (1942),and it is derived from the Greek words Anti-against and bio-life, together they mean 'against life' .

⇒Antibiotics are the chemical substances, produced by some microbes that can kill or retard the growth of other disease causing microbes. The first anibiotic discovered

was penicillin. 

⇒Alexander Fleming, while working on Staphylococci bacteria, found a mould growing in one of his culture plates.

 ⇒This mould produced a chemical, which inhibits the bacterial growth. It was named as penicillin after the mouldPenicillium notatum. 

Chemicals, Enzymes and bioactive Molecules :

Microbes are being used for commercial and industrial production of certain chemicals like alcohols, organic acids,enzymes and other bioactive molecules .Some of them are given below:

Organic acids :

Citric acid      ⇒ Aspergillus niger (fungus)

Acetic acid    ⇒  Acetobacter aceti (bacterium)

Buryric acid  ⇒Clostridium butylicum(bacteria)

Lactic acid    ⇒Lactobacillus (bacteria)

Enzyme :

⇒Lipases :

 Used in formulation 

⇒Pectinases:

Used in bottled juices 

⇒Streptokinase:

Used as 'clot buster' for removing clots in vesseles

Microbes as Biofertilizers :

Biofertilizer are organism that enrich the nutrient quality of soil by enhancing the availability of nutrients to the crops.

Bacteria :

Nitrogen fixing symbiotic bacteria -Rhizobium

Free living Nitrogen fixing bacteria-Azotobacter

Fungi :

The symbiotic association with plants and mycorrhiza,which absorb phosphorous from soil. Many members of genus Glomus form mycorrhiza. 

Cyanobacteria:

These are autotrophic microbes found in aquatic and terrestrial environments. Some examples are Anabaena,Nostoc,Oscillatoria,etc.. Blue Green algae (BGA) also add organic matter to the soil.

These were the general uses of microbes in day-to-day life.