Micro-organisms around us

Microorganisms or microbes are organisms that can not be seen with the naked eye but with the help of a microscope. They can be found all around in water, air and in the soil even inside other organisms. Most microorganism are not harmful and can be helpful in decomposition. Some even aid digestion in some other organisms.

Some microorganisms are very harmful in that they cause illness, bad smells and even destroy other organisms.

Types of Microorganisms

Bacteria are microscopic single-celled organisms, prokaryotic in nature, that thrive in diverse environments. Typically a few micro-meters in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats.

Fungus (pl: Fungi) is eukaryotic in nature ( which means they have a defined nucleus and organelles) which includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, fungi, which is separate from the other eukaryotic cells found in other organisms. The cells are larger than prokaryotes such as bacteria. Fungal colonies can be visible to the human eye once they have achieved a certain level of growth, for example mould on bread.

Viruses are considered by many experts as non-living. They are made up of nucleic acid (DNA or RNA,) and a protein coat. A virion (a virus particle) requires a host cell in order to replicate. Within the human anatomy a virus enters a human cell and takes it over, using the cell to replicate. In many cases the immune system detects the presence of the virus and takes action leaving us with the symptoms of a common cold or influenza. Some viruses can cause permanent and irreversible damage to cells, for example HIV.

Algae, singular alga, members of a group of predominantly aquatic photosynthetic organisms of the kingdom Protista. The are morphologically simple, chlorophyll-containing organisms that range from microscopic and unicellular (single-celled) to very large and multicellular. The algal body is relatively undifferentiated and there are no true roots or leaves.

economic importance of microorganisms

1. Food processing: such as fermentation which is the process of converting carbohydrates to alcohol or organic acids using microorganisms such as yeasts or bacteria, under anaerobic conditions. Fermentation usually implies that the action of microorganisms is desired. The science of fermentation is known as zymology or zymurgy.

2. Biotechnology: is the use of microorganisms including bacteria and fungi in the manufacturing and services industries. These include chemical manufacturing such as ethanol, acetone, organic acid, enzymes, and perfumes. In the chemical industry, bacteria are most important in the production of pharmaceuticals. Escherichia coli is used for commercial preparation of riboflavin and vitamin K.

3. Genetic engineering: is the manipulation of genes. In genetic engineering, pieces of DNA (genes) are introduced into a host by a variety of techniques, one of the earliest being the use of a virus vector. The foreign DNA becomes a permanent feature of the host, and is replicated and passed on to daughter cells along with the rest of its DNA. Bacterial cells are transformed and used in production of commercially important products. The examples are production of human insulin (used against diabetes), human growth hormone (somatotrophin) used to treat pituitary dwarfism, and infections which can be used to help fight viral diseases. Using biotechnology techniques, or bio medical technology bacteria can also be bio-engineered for the production of therapeutic proteins

4. Fibre retting: is a process employing the action of micro-organisms and moisture on plants to dissolve or rot away much of the cellular tissues and pectins surrounding bast-fibre bundles, and so facilitating separation of the fibre from the stem.

5. Digestion: Some bacteria living in the gut of cattle, horses and other herbivores secrete cellulase, an enzyme that helps in the digestion of the cellulose of plant cell walls. Cellulose is the major source of energy for these animals. The Escherichia coli that live in the human large intestine synthesizes vitamin B and releases it for human use.

6. Pest control: Bacteria can also be used in the place of pesticide in biological pest control.

7. Agents of disease: Bacteria cause a wide range of disease in humans and other animals. Plant diseases caused by bacteria are commercially important worldwide for agriculture. Besides bacterial pathogens that are already established in many areas, there are many instances of pathogens moving to new geographic areas or even the emergence of new pathogen variants. In addition, bacterial plant pathogens are difficult to control because of the shortage of chemical control agents for bacteria.

8. Food spoilage: saprophytic bacteria attack and decompose organic matter. This characteristic has posed a problem to mankind as food such as stored grains, meat, fish, vegetable and fruits are attacked by saprophytic bacteria and are spoiled. Similarly dairy products and other agricultural products are easily contaminated by bacteria and spoiled.