Microbes in Human Welfare Comprehensive Study Guide

Microbes in Household Products

  • Lactic Acid Bacteria (LAB):

    • Microbes such as Lactobacillus and others commonly called Lactic Acid Bacteria (LAB) grow in milk and convert it into curd.

    • During growth, the LAB produce acids that coagulate and partially digest the milk proteins.

    • Nutritional Enrichment: Curd preparation increases the nutritional efficiency of milk by increasing the content of Vitamin B12B_{12}.

    • Health Benefits: In the human stomach, LAB play a very beneficial role in checking and inhibiting disease-causing microbes.

  • Yeast (Saccharomyces):

    • Bakery Applications: Used in the production of bread. The "puffed-up" appearance of dough is due to the production of CO2CO_2 (carbon dioxide) gas during fermentation.

    • Brewery Applications: Used for the fermentation of malted cereals and fruit juices to produce alcohol.

  • Traditional Drinks:

    • Toddy: A traditional drink in some parts of Southern India, made by fermenting the sap from palm trees.

Microbes in Industrial Products

  • Scale of Production: On an industrial scale, microbes are grown in very large vessels called fermentors to produce products in mass quantities.

  • Alcoholic Beverages:

    • Microbes, specifically yeast, are used for the production of beverages like wine, beer, whisky, brandy, and rum.

    • Without Distillation: Wine and Beer are produced without the distillation process.

    • With Distillation: Whisky, Brandy, and Rum are produced by the distillation of the fermented broth.

Discovery and Impact of Anti-Biotics

  • Etymology: The term "Anti-biotic" is derived from Greek words; "Anti" means against and "Bio" means life (referring to being against the life of disease-causing organisms).

  • Penicillin:

    • It was the first anti-biotic to be discovered.

    • Discovery: Discovered by Alexander Flemming while working on Staphylococci bacteria.

    • Development: Its full potential as an effective anti-biotic was established much later by Ernst Chain and Howard Florey.

    • Recognition: Alexander Flemming, Ernst Chain, and Howard Florey were awarded the Nobel Prize in 1945 for this discovery.

Microbial Production of Industrial Acids

Microbes are used for the commercial and industrial production of certain organic acids:

  • Citric Acid: Produced by the fungus Aspergillus niger.

  • Acetic Acid: Produced by the bacterium Acetobacter aceti.

  • Lactic Acid: Produced by the bacterium Lactobacillus.

  • Butyric Acid: Produced by the bacterium Clostridium butylicum.

Microbes in Cheese Production

Cheese is one of the oldest food items in which microbes were used. Different varieties of cheese are known by their characteristic texture, flavor, and taste, which come from the specific microbes used:

  • Swiss Cheese: Characterized by large holes. These holes are due to the production of a large amount of CO2CO_2 by the bacterium Propionibacterium sharmanii.

  • Roquefort Cheese: This cheese is ripened by growing a specific fungus, Penicillium roqueforti, on them, which gives them a particular flavor.

Microbial Enzymes and Their Applications

Enzymes are produced using microbes for various industrial and domestic applications:

  • Lipases: These are used in detergent formulations and are helpful in removing oily stains from laundry.

  • Proteases and Pectinases: These enzymes are used for the clarification of bottled fruit juices, making them clearer compared to those made at home.