Microbes: Invisible superheroes
The word ‘bacteria’ generally is always coupled with a negative connotation in day to day life. This is because bacteria are mostly associated with diseases that afflict us. However, there exist a plethora of bacteria which are highly beneficial and crucial to the existence of mankind. . We have failed to realize their significance, their positive impact on our life and their contribution towards sustaining life on earth since the beginning of time.
If we have a look at our surrounding, most the products used by us are of microbial origin. Bread, cheese, wine, beer, antibiotics, fossil fuels like petrol & diesel, curd, yogurt, enzymes in detergents etc are all traditionally being synthesized by micro-organisms. The wrong notion about bacteria and viruses might be due to lack of information, miscommunication, false beliefs or poor scientific knowledge.
Vaccines such as BCG, tetanus, MMR, cholera etc is all made from attenuated or denatured bacteria. Vaccines thus help us in strengthening our immune system. In technical terms, vaccines are just introduction of antigens which would stimulate our immune system to produce antibodies. This wouldn’t have been possible without microbes.
The human gut is a big universe of micro-organisms. In the gut there are millions of bacteria helping us to digest our food. Most of the enzymes secreted by them help us in utilizing the complex food material that we eat. It has now been established that metabolism of an individual is directly related to the type of gut flora present in their system. Gut flora has also been linked as a marker of overall health of an individual. Probiotics are micro-organisms that are consumed by us which help in creating a balance in the gut. Probiotics also have a great significance during antibiotic treatment since antibiotic non-selectively damage our gut flora, probiotics help in restoration of the same. Lactobacillus, Bifidobacterium, Streptococcus & Saccharomyces are some good examples of probiotics. These organisms also help in elimination of pathogens like Salmonella, Shigella, Vibrio etc.
Some strains of microbes act as good feed additives for domesticated animals. These microbes provide resistance to animals from pathogenic microbes. They also help in reduction of use of antibiotics which are used in great amounts in animal feed. Saccharomyces cerevisiae is very commonly used as animal feed. Some species of Actinomycetes are added to animal feed in order to protect them from other pathogens.
The great fossil fuels on which our society is completely dependent is a result of combined action of many microbes degrading organic matter buried in deep layers of earth. Under anaerobic conditions, microbes use up all the dead remains of animals & plants for their energy production. This results in production of petrol and diesel. Antibiotics like penicillin, streptomycin, erythromycin, glycopeptides, vancomycin etc are all produced by various species of fungi, bacteria and actinomyectes. These antibiotics are proved boon to mankind in treatment of life threatening conditions. Example can be given of World War II which has witnessed a great use of Penicillin in saving many lives of the wounded soldiers.
Apart from these microbes do have some specialized roles. Biogas formation is one such phenomenon. Thermophiles which are stable at high temperatures are very crucial in formation of biogas. Since biogas is made using waste material, there are chances of coliforms like Escherichia coli, Klebsiella pneumonia etc growing them. Thermophilic microbes like Methanococcus, Methanobacter & Methanothrix help in eliminating these pathogens.
Microbes are not only restricted to biogas production but also play a major role in remediation of soil. Pseudomonas putida, a gram negative bacterium is widely used in bioremediation of oil spills, pesticides, organophosphates, hydrocarbons, BTEX compounds . The major impact of these pollutants is seen in water bodies and soils. Physical and chemical methods of remediation have many limitations and drawbacks. Biological method does not harm the environment but also helps in restoration. Species of Pseudomonas are widely used in bioremediation due to their to grow quickly, surfactant production which helps in easy utilization of oils & ability to utilize various types of carbon sources. Yeast such as Rhodotorula and Rhodobacter are very helpful in degradation of naphthalene, benzene, xylene, toluene and its derivatives.
In agricultural sector, microbes have a great economic importance. Micro-organisms in rhizosphere help in development of plant. Their mode of action is by secretion of growth hormones like Indoleacetic acid, Gibberellic acid, cytokinnins, auxins, siderophores etc. Pseudomonas species are well known for siderophore production and hence help in making iron available to the plants. Azotobacter & Rhizobium species fix atmospheric nitrogen and make it available to the roots. These microbes collectively help in plant growth promotion. Bacillus species have variety of applications. Some species act as biopesticide and therefore help in reduction of plant disease. Bacillus species are reported to have antifungal and anti-nematode activity. Bacillus megaterium is used in farms for solubilisation of phosphates and other minerals. Bacillus subtilis spores are sprayed on crops to prevent damage caused by fungus. The very famous Bacillus thuringenesis (Bt) is a known biopesticide and genes from them are used to develop disease resistant varieties of many crops. Pseudomonas florescens acts as plant growth promoter by secreting siderophores, which chelate iron and this is utilized by the plants. Pseudomonas aureofaciens has a great anti-nematode activity. These microbes can also develop biofilms and provide a protection to the developing crops. Some species of micro-organisms are well known for degrading pesticides that are sprayed on crops. This helps in elimination of pesticide residues and thus makes it fit for consumption. Fungal species such as Trichoderma is used to inhibit the growth of plant pathogens such as Fusarium, Xanthomonas etc. Many microbes are also used as vectors to transfer disease resistant genes to plants. Agrobacterium tumefaciens Ti-plasmid is an example of a vector which is used on a regular basis for this purpose.
Apart from all these applications, microbes have significant uses in industries too. Aspergillus niger on commercial basis is used for production of citric acid. Many vitamins are also produced by microbes by fermentation technology. Immuno-suppressive drugs, recombinant vaccines, anti-tumor drugs etc are examples of biosimilars and biologics that are safely made in recombinant strains of micro-organisms. Various detection kits are now available in market for disease detection are manufactured by using antigens which are isolated from microbes. Industrial enzymes such as Amylase, Protease, Cellulase, Xylanase etc are produced using large scale fermentation by microbes. Monoclonal antibodies are also manufactured using microbes. Thus if we see the current scenario, products having great impact on humans are generally developed from microbes. Basic food i.e. bread is made using baker’s yeast.
In effluent treatment plants, microbes are added to secondary treatment tanks to lower the BOD & COD of the effluents. Some microbes also help in bioremediation of heavy metals found in effluents. Growth of filamentous bacteria in effluent tanks helps in flocculation and easy formation of sludge.
The list of applications above mentioned is just a small drop from the ocean of microbes and their various widespread uses. So, next time if you hear the word ‘BACTERIA’, you shouldn’t get scared or worried. Relax, sit back and think of them AS YOUR FRIENDLY INVISIBLE SUPERHERO ready to work for you at your disposal and make your life easier.
ENJOY THE WORLD OF THESE MYSTERIOUS YET FASCINATING MICRO-ORGANISMS!!!