Industrial Microbiology

Industrial importance of BACTERIA

Written by MicroDok

Bacteria are prokaryotic cells. They are single celled microorganisms that are ubiquitous in nature. Morphologically, bacteria measure between 0.5 to 10 µm in diameter. Bacteria exist in different shapes. Some are cocci (spherical), rod-shaped (bacilli) or spiral in shape. Bacteria are of economic importance because they cause disease in plants, animals and humans. They are also employed in various industrial processes for the production of goods/products that are of significance to man, animals, plants and the environment. Their mode of nutrition is simple and they can derive their energy and carbon from organic and inorganic materials in their environment. They grow in the presence of oxygen (aerobic bacteria) or in the absence of it (anaerobic bacteria). Some bacteria are facultative organisms since they can thrive either in the presence or absence of oxygen.

Bacteria reproduce by binary fission, in which a bacterial cell wall divides into two cells. Bacteria have a simple cell structure and they lack membrane bound organelles since they are prokaryotic cells. Bacteria can also exist as single cells in pairs (diplococci), in chains (streptococci) or in clusters (staphylococci). Some bacteria are comma shaped bacteria (e.g. Vibrio cholerae) while others are corkscrew in shape (e.g. spirochetes). Bacteria have extrachromosomal genetic elements known as plasmids; and these plasmids are different from the chromosome or DNA of the organism. Bacterial plasmid can be transferred from one organism to another through genetic transfer mechanisms such as conjugation, transduction and transformation. Bacteria also cause food spoilage and some infectious diseases.

Bacteria of industrial importance are found in the genus Bacillus, Streptomyces, Lactobacillus, Clostridium, Escherichia, Leuconostoc, Acetobacter, and Azotobacter and Xanthomonas.

Based on the product of their fermentation, bacteria can be classified as:

  • Lactic acids bacteria.
  • Acetic acid bacteria.
  • Propionic acid bacteria.
  • Some bacteria break down protein and may be called proteolytic bacteria.
  • Those that break down lipids are called lipolytic bacteria.
  • Those that breakdown sugars are called saccharolytic bacteria.
  • Streptococcus, lactobacillus, and bacillus produce lactic acid.
  • Escherichia coli produce ethanol and acetic acid including CO2 and hydrogen.
  • Vinegar, wine and beer are some foods and beverages in which the fermentative actions of bacteria are applied in their production.

INDUSTRIAL SIGNIFICANCE OF BACTERIA

  • Bacteria are employed in bioleaching activities – in which insoluble metals are converted into soluble metals. Many bacteria such as the iron reducing bacteria thrive by reducing ferric iron [Fe (III)] to ferrous iron [Fe (II)], and Mn (VI) to Mn (II). These bacteria can be used to leach Fe (III) and Mn (VI) metals from some soils and sediments and to form a range of reduced materials, which can include magnetite and siderite. The ability of these organisms to do this can result in a change in sediment structure; and this holds the potential to control water flow in aquifers. These bacteria could also be exploited to produce biomaterials such as magnetite that are of commercial value.
  • Bacteria produce enzymes that drive fermentation processes.
  • They are important for the production of proteins.
  • Bacteria are important for the production of amino acids and vitamins.
  • Xanthomonas species, a proteobacterium exhibit the ability to produce the acidic exopolysaccharide commonly marketed as xanthan gum. Xanthan gum is used as a thickening and stabilizing agent in foods and in cosmetic ingredients to prevent separation.
  • Corynebacterium glutamicum produces the amino acid, glutamic acid. Glutamic acid is used as a common additive in food production, where it is known as monosodium glutamate (MSG).
  • Corynebacterium species are often used to mass produce amino acids utilized in food processing.
  • Corynebacterium species can also be used in steroid conversion and in the degradation of hydrocarbons; and each of these processes are significant in pharmaceutical industry and in the cleanup of the environment respectively. For example, steroid conversion is an important process in the development of pharmaceuticals used for the treatment of infectious diseases while the degradation of hydrocarbons such as oil is important in the breakdown and elimination of environmental toxins.
  • They take part in the production of acetic acid that is important for the production of certain foods.
  • Bacteria produce lactic acid that is used in the production of certain food.
  • Most antibiotics can be naturally sourced or produced from bacteria.
  • Bacteria are employed in the production of biofertilizers.
  • Insulin is now largely produced from a genetically modified bacterium, Escherichia coli. Insulin was previously sourced from the pancreas of slaughtered pigs and cows. Genetically engineered microbes produce insulin in a pure form that is less likely to cause allergic reactions than insulin from the pancreas of slaughtered cows and pigs.

References

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Nduka Okafor (2007). Modern industrial microbiology and biotechnology. First edition. Science Publishers, New Hampshire, USA.

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