The world of microbes

The world of microbes: microbes and human welfare

Have you ever thought that how much useful are these invisible friends (not all microbes) of human beings. Although present everywhere where life can exist, they are difficult (except in colonies) to see by naked eyes, discernible only under the microscope. They have been used by the humans and nature for decades in several processes to produce useful products.

1. Household products:

2. Industrial products

3. Alcoholic Fermentation

4. Antibiotics

5. Chemical enzymes

6. Bioactive molecules

7. Sewage treatments

8. Biogas

9. Biocontrol agents

10. Biopesticides

11. Biofertilizers

Household products:

1. Milk products:

Several products of milk like curd, yoghurt, butter milk and cheese etc. are used and consumed by us as per our preference. Lactic acid bacteria (LAB) are added to milk to change milk into these abovementioned products. The starter/inoculum contains millions of LAB.

Product Bacteria

Curd Lactobacillus acidophilus

Yoghurt Streptococcus thermophilus/Lactobacillus bulgaricus

Butter Milk Streptococus cremoris, S. lectis, L. acidophilus,Leuconostoc spp.

Sour Cream Streptococus lectis, Leuconstoc cremoris

Cheese LAB + enzyme rennin (for curdling)

Swiss Cheese Propionibacterium sharmanii (CO2 producing bacteria)

Roquefort Cheese Pencilium roqueforti

Camebert Cheese Pencilium Cameberti

2. Other eatables:

Bread, Dosa, Uppma, Idli, Tempeh, Tofu, Sufu and sausages are prepared using different species of microbes.

Product Bacteria

Bread Saccharomyces cerevisiae used as yeast

Dosa/Uppama/Idli Leuconostoc/Streptococus spp.

Single Cell Protein Spirulina/yeast/fusarium graminearum

Industrial Products:

1. Alcoholic Fermentation:

Yeast species used are Saccharomyces cerevisiae (Brewer’s yeast, S. ellipsoidens (Wine yeast), S. sake (Sake yeast) and S. pireformis (Ginger beer?Ale yeast).

Nutrient medium for different alcoholic products are listed below.

Alcoholic product Nutrient medium

Beer Barley malt

Gin Fermented Rye malt

Sake Fermented rice

Fenny Cashew apple

Vodka Potato

Whisky Fermented cereals

Rum Fermented molasses

Wines and Brandy Fermented juices

2. Antibiotics:

Antibiotics are substances produced by microorganisms like lichens, fungi, eubacteria and actinomycetes

Antibiotic Source

Tyrothricin Bacillus brevis

Pencillin Pencillium notatum

Neomycin Streptomyces fradiae

Viridin Gliocladium virens

Streptomycin Streptomyces griseus

Chloromycetin S. lavendulae

Tetracyclines S. aureofaciens

3. Organic acids: Several acids like acetic acid, citric acid, lactic acid and gluconic acid are prepared with the help of microorganisms.

Acid Microorganism

Acetic acid Acetobacter aceti

Citric acid spergillus niger/Mucor spp.

Lactic acid Bacteria (S. lactis) + fungi (Rhizopus)

Gluconic acid Aspergillus niger/Pencillium spp.

4. Enzymes:

Enzyme Source Uses

Proteases Mortierella renispora Chill proffing (beer and whisky)

Amylases Aspergillus/Rhizopus Alocolic beverages

Rennet Extract from stomach of calf Preparation of cheese

Leectases Saccharomyces fragilis Converts lectose into lactic acid

Pectinases Byssochailmys fulvo For clearing fruit juices

Lipases Candida lipolytica Used in detergents

5. Statins: they are product of fermentation activity of yeast Monascus purpureus. Statins are used in lowering blood cholesterol.

Sewage treatment:

Floc is formed by different types of bacteria, filamentous fungi, yeasts and protozoans. Microbes digest a lot of orgnic matter and convert it into microbial biomass and release lot of minerals.

Biogas: Methane bacteria convert organic acids as well as carbon dioxide into methane

Biological control of diseases and pest: Trichoderma, Phytopphthora palmivora, Baculovirus heliothis and Baculoviruses.

Biofertilizers: Some bacteria fixes atmospheric nitrogen.

Azatobacter, Bacillus, clostridium are saprotrophic bacteria

Rhodopseudomonas, Rhodospirillum, Chromatium are photoautotrophic bacteria

Symbiotic Nitrogen Fixing Bacteria: fix nitrogen from the atmosphere and take food from the plant. Plant uses this nitrogen for their growth. Rhizobium spp. are such type of bacteria. Blue green algae Anabaena azollae resides in the leave cavities of Azolla pinnata fern. Mycorrhiza fungus forms a association with the roots of a plant . It is useful for utilization of phosphorus.