Microbes in Human Welfare Test - 15

Industrial utilisation of bacteria and other microbes involves three processes- laboratory-scale process, pilot plant scale and manufacturing unit. The development from the laboratory scale to the manufacturing unit is called as scaling up.

The container where fermentation is carried out is called a bioreactor. It has an aeration system, pH correctors and temperature adjustors. Bioreactors are often large.

Microorganisms are added in bioreactors in three ways-
i. Added on the surface of the nutrient medium
ii. Suspended in a nutrient medium
iii. Placed in calcium alginate beads.

Louis Pasteur found for the first time that beer and buttermilk are produced due to the activity of yeast and yeast-like organisms. Saccharomyces cerevisiae is the most common yeast used.

Saccharomyces ellipsoidens is commonly known as wine yeast. Brewer’s yeast, Sake yeast and Ale yeast are known as Saccharomyces cerevisiae, Saccharomyces sake and Saccharomyces piriformis respectively.

The nutrient medium for beer is barley malt. Fermented cereals, molasses and juices are the nutrient medium for whisky, rum and wine respectively.

Fermentation occurs in 3 ways- batch process, continuous process and feed batch process. Feed batch process is an intermediate process between batch and continuous processes.

In the case of beer, the fermented liquor has an alcohol content of 3-6%. The alcohol content is 10-27% in wines, 60-70% in brandy and 95% in rectified spirit.

The by-products of alcoholic fermentation are CO₂ and ethanol. Several other chemicals can be formed with the change of nutritive medium, pH and aeration like n-propanol, butanol, glycerol, acetic acid, pyruvic acid, succinic acid, lactic acid, caproic acid, ethyl acetate etc.

Beer contains 3-6% alcohol. Nutrient medium is barley. Beer is allowed to age before pasteurisation. Large beer is prepared by carrying out ageing in the cold.

Champagne is the most popular sparkling wine, sparkling wines are naturally carbonated due to the continuation of fermentation after bottling. Other famous wines are port wine and sherry wine.

Wine is an alcoholic beverage prepared from ripe fruits and fruit juices. Its alcohol content is formed about 10-27%. Red wine is red due to the colour of the grape skin. Cider is apple wine.

Whisky and other alcoholic drinks are prepared through distillation as the maximum content of alcohol in fermentation. Good whisky contains about 40% alcohol. 

The term antibiotics was coined by Waksman in 1942. Clinically, an antibiotic is a substance produced by a microorganism which is in low concentration and inhibits the growth and metabolic activity of pathogenic organisms without harming the host.

The first antibiotic is generally associated with the name of Alexander Fleming when he discovered Penicillin from Penicillium notatum in 1928. Penicillium notatum did not allow the growth of Staphylococcus aureus.