(a) Lactic acid: Lactic acid is commercially produced from pasteurized whey (the watery part of milk) through fermentation caused by Lactobacilus bulgaricus and L. delbrueckii.
(b) Curd: Curd is prepared from pasteurized milk by the process called curdling. It is initiated by adding a starter culture of Lactobacillus bulgaricus and Streptococcus thermophillus, into the milk at 40°C. Lactobacillus converts lactose to lactic acid whereas Streptococcus causes coagulation of casein due to acidity.
(c) Cheese: Preparation of cheese from the milk involves two main steps – first curdling of milk, and second the subsequent ripening of solid curd by the use of different bacterial strains.
(d) Butter: It is prepared by churning of sweet or sour cream. The microorganisms responsible for preparation of butter cream are – Streptococcus lactis and Leuconostoc citrivorumare. The characteristic butter aroma develops due to a volatile substance – diacetyl. It is produced by the action of streptococcus on pasteurized milk.
(e) Retting process: Fibres of flax, hemp and jute are separated by the process called retting. During this process the stems of the plants are submerged in water, where the bacterial activity results in the rotting of softer parts. The tough bast fibres become loosened and easily separated from each other. These fibres are spun and woven into various articles.
(f) Vinegar: Country made vinegar is a fermentation product of cane juice, molasses or fruit juices. It is produced in two steps – first conversion of sugars into alcohols by alcholic fermentation carried by yeast, and the second, conversion of alcohol to acetic acid by the action of bacteria Acetobacter (A. orieansis, A. acetic, A. schuizenbachi, etc.). Vinegar is used in the preparation of pickles or in place of acetic acid. It is used as preservative of meats and vegetables.
(v) Role of bacteria in human being: E.coli (gram-ve) bacteria live in colon region of intestine of man and other animals and play an important role in digestion process.
(vi) Medicinal uses
(a) Vitamins: Production of riboflavin (vitamin B2) involves the activity of bacterium – Clostridium butyticum. The well known vitamin C (ascorbic acid) is produced from sorbital by the action of Acetobactor spp.
(b) Serum and vaccines: Many bacteria are used in the preparation of serums and vaccines. These substances induce immunity to various diseases in man. Serums are effective against certain diseases like diphtheria, pneumonia, etc., whereas the vaccines are effective against typhoid, smallpox, cholera, etc.
(c) Enzymes: Some bacteria live in the alimentary canal of herbivorous animals like cow, horse, goat, etc. and help in the production of certain enzymes which digest the cellulose. The enzymes proteases are produced by bacteria Bacillus subtilis. Similarly, the enzyme pectinase is produced by Clostridium sp, which is used in retting of flax.
(d) Antibiotics: These are the chemical substances produces by living microorganisms capable of inhibiting or destroying other microbes. These are the products of secondary and minor metabolic pathways, mostly secreted extracellularly by the microorganisms. These are used in controlling various infectious diseases.
At present more than 5000 antibiotic substances are known and approximately 100 are available for medicinal use. The most important bacterium which produces maximum number of antibiotics is Streptomyces.
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(b) Curd: Curd is prepared from pasteurized milk by the process called curdling. It is initiated by adding a starter culture of Lactobacillus bulgaricus and Streptococcus thermophillus, into the milk at 40°C. Lactobacillus converts lactose to lactic acid whereas Streptococcus causes coagulation of casein due to acidity.
(c) Cheese: Preparation of cheese from the milk involves two main steps – first curdling of milk, and second the subsequent ripening of solid curd by the use of different bacterial strains.
(d) Butter: It is prepared by churning of sweet or sour cream. The microorganisms responsible for preparation of butter cream are – Streptococcus lactis and Leuconostoc citrivorumare. The characteristic butter aroma develops due to a volatile substance – diacetyl. It is produced by the action of streptococcus on pasteurized milk.
(e) Retting process: Fibres of flax, hemp and jute are separated by the process called retting. During this process the stems of the plants are submerged in water, where the bacterial activity results in the rotting of softer parts. The tough bast fibres become loosened and easily separated from each other. These fibres are spun and woven into various articles.
(f) Vinegar: Country made vinegar is a fermentation product of cane juice, molasses or fruit juices. It is produced in two steps – first conversion of sugars into alcohols by alcholic fermentation carried by yeast, and the second, conversion of alcohol to acetic acid by the action of bacteria Acetobacter (A. orieansis, A. acetic, A. schuizenbachi, etc.). Vinegar is used in the preparation of pickles or in place of acetic acid. It is used as preservative of meats and vegetables.
(v) Role of bacteria in human being: E.coli (gram-ve) bacteria live in colon region of intestine of man and other animals and play an important role in digestion process.
(vi) Medicinal uses
(a) Vitamins: Production of riboflavin (vitamin B2) involves the activity of bacterium – Clostridium butyticum. The well known vitamin C (ascorbic acid) is produced from sorbital by the action of Acetobactor spp.
(b) Serum and vaccines: Many bacteria are used in the preparation of serums and vaccines. These substances induce immunity to various diseases in man. Serums are effective against certain diseases like diphtheria, pneumonia, etc., whereas the vaccines are effective against typhoid, smallpox, cholera, etc.
(c) Enzymes: Some bacteria live in the alimentary canal of herbivorous animals like cow, horse, goat, etc. and help in the production of certain enzymes which digest the cellulose. The enzymes proteases are produced by bacteria Bacillus subtilis. Similarly, the enzyme pectinase is produced by Clostridium sp, which is used in retting of flax.
(d) Antibiotics: These are the chemical substances produces by living microorganisms capable of inhibiting or destroying other microbes. These are the products of secondary and minor metabolic pathways, mostly secreted extracellularly by the microorganisms. These are used in controlling various infectious diseases.
At present more than 5000 antibiotic substances are known and approximately 100 are available for medicinal use. The most important bacterium which produces maximum number of antibiotics is Streptomyces.
▬▬▬▬▬▬▬▬▬▬▬▬▬
📚JOIN: @Ethio_Educational_News
📚JOIN: @EUEE_TIPS
📚JOIN: @Et_Study_Notes