Microbiology: The Science in Service of Environment and Humanity

Alka Sagar*, Abhinav Singh, Sonia Sharma and Asif Siddiqui Department of Biotechnology & Microbiology Meerut Institute of Engineering & Technology, Meerut

2021-08-22 16:42:24

Credit: pixabay.com

Credit: pixabay.com

Microorganism, the omnipresent micro-sized creatures are contributing their services in environment safekeeping, augmenting and making it safe for the survival of human civilization. Microbial processes are associated with production of healthier food supplements, nutrient cycling, biodegradation, climate change, production of environment friendly alternatives to non-degrading synthetic materials and bioremediation of toxic wastes. Various microbial species contribute in production of biofuels or bioplastics as environmental-friendly, less-polluting alternatives. Other species are contributing in bioremediation processes to reduce the toxic substances.

Key words: Microbes, Microbial processes, Biofuels,   Nutrient Cycling


Since time immemorial, microbial processes are associated with our house hold activities like making fermented food. Then nobody knew why & how a raw food material changed into a useful food product.  Now we deal with many different kinds of microorganisms for both culinary & other domestic purpose. Microbes are very useful and also harmful to humans and to the environment as well. They play crucial roles in nutrient cycling, biodegradation, climate change, the cause and control of the disease. They are widely employed in many ways like manufacturing biofuels, cleaning up pollution, producing or processing of drinks and food-products. Our world is on the brink of a revolution, accelerated by microorganisms. Thanks to microorganisms, we have products which have capacitated us to lead healthier life and make great progress.(1,2) Nowadays microbiology offers plethora of opportunities for human welfare and developing an improved environment.

Some aspects are as follows:

Bioplastic:Plastic, the biggest threat for environment & humans finds enormous application in context to food related items from packaging, crockery, cutlery, pots, bowls, to straws. Bioplastic is the emerging solution. Bioplastics are the plastics that are made from renewable resources and able to break down naturally. These innovative plastic materials are produced from renewable biomass sources by enabling specific microbial activities on material such as vegetable fats and oils, corn starch, straw, woodchips, sawdust, recycled food waste, etc. (3,4).Bioplastic can also be made from agricultural by-products and also from used plastics by using microorganisms. Bioplastics are usually derived from sugar derivatives, including starch, cellulose, and lactic acid. Poly-(3-)hydroxybutyrate (PHB) and poly-(3-)hydroxyalkanoate (PHB) are the two chief classes of bioplastics. PHB is synthesised by Bacillus megaterium and Ralstonia eutropha whereas, PHAs are chiefly harvested from Pseudomonas oleovorans , P. putida and Alcaligenes eutrophus. Various other chief contributing microbial agents include Chromatium vinosum, Brevibacterium epidermidis, Clostridium kluyveri,  Rhizobium (Cicer) sp.,  Thiocystis violacea, Thiocapsa pfennigii and Synechocystis sp.(5,6)  

Biofuel: Biofuel, is any fuel that is derived from biomass i.e. plant or algae material or animal waste. It is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas. Biofuels include bioethanol (often made from corn and sugarcane), biodiesel (sourced from vegetable oils and liquid animal fats), green diesel and biogas (methane derived from animal manure and other digested organic material as microbial metabolic by-product)(7) . Green diesel can b obtained by plant products of Jatropha curcas, Soybean and oil palm, seeds of the tropical plants Anacardium occidentale L (cashew), Cocos nucifera (coconut palm) and Gossypium hirsutum (upland cotton) by microbial activities of Tetradesmus obliquus, Botryococcus braunii, Spirulina, Chlorella vulgaris, Spirulina maxima, Nannochloropsis sp., Neochloris oleoabundans, Scenedesmus obliquus and Dunaliella tertiolecta.  Similarly, Methanobacterium, Methanoculleus , Methanobrevibacter, Methanolinea and Methanosaeta  aid in biogas production from ruminant excreta and other digested organic material as a metabolic by-product. Microbes also find application in environment safekeeping & are used to produce bio-ethanol which is produced from lingocellulose, cellulose and hemicellulose (constituents of plant cell wall) by Klebisella oxytoca and Saccharomyces cerevisiae.(8,9). The enzymes for their breakdown are cellulose, lignase etc and are found in various microbial species. These enzymes are extracted from Trichoderma sp.,  Aspergillus terreus, Cyathus stercoreus, Lentinus squarrosulus, Lentinus edodes, Pleurotus sp., Penicillium camemberti and various other microbial sources.(10)


Bioremediation is another environment favoring branch of microbiology that employs the use of living organisms, like algae and bacteria, in the removal of contaminants, pollutants, and toxins from soil, water, and other environments. (11)Bioremediation relies on stimulating the growth of certain microbes that utilize contaminants like oil, solvents, and pesticides for sources of food and energy. These microbes convert contaminants into small amounts of water, as well as harmless gases like carbon dioxide. (12)  It finds application in cleaning up oil spills or contaminated groundwater. Bioremediation may be done "in situ"–at the site of the contamination–or "ex situ"–away from the site.  It requires a combination of the right temperature, nutrients, and foods. Bioremediation is less expensive and more sustainable than other remediation alternatives(13). Biological treatment is a similar approach used to treat wastes including wastewater, industrial waste and solid waste. (14,15). Some examples of bioremediation related technologiesinclude phytoremediation, mycoremediation, bioventing, bioleaching, landfarming, bioreactor,composting, bioaugmentation, rhizofiltration, and biostimulation. (16). Common microbial agents for bioremediation are Pseudomonas putida, Dechloromonas aromatica, Deinococcus radiodurans, Methylibium petroleiphilum, Alcanivorax borkumensis and Phanerochaete chrysosporium.( 17, 18).


Probiotics are live microorganisms that when consumed, provides health benefits and improves or restores the gut flora. The most important medicinal properties displayed by microbial strains used as probiotic  include: resistance to gastric acidity, bile acid resistance, adherence to mucus and human epithelial cells and cell lines, antimicrobial activity against potentially pathogenic bacteria or fungi, ability to reduce pathogen adhesion to surfaces, bile salt hydrolase activity, enhancing viability of probiotics. (19). Health benefits have mainly been demonstrated for specific probiotic strains like LactobacillusBifidobacteriumSaccharomycesEnterococcusStreptococcusPediococcus, LeuconostocBacillusEscherichia coliLactobacilli sp. are used for the production of yogurt, cheese, sauerkraut, pickles, sourdough, wine and other fermented products.

They are a major part of the lactic acid bacteria (LAB) group, which also includes LactobacillusLactococcusEnterococcusOenococcusPediococcusStreptococcus and Leuconostoc species,  which can convert hexose sugars to lactic acid thus producing an acid environment which inhibits the growth of several species of harmful bacteria  Similarly, several strains of Bifidobacteria are considered as important probiotics including: Bifidobacterium infantisB. adolescentisB. animalis subsp animalisB. animalis subsp lactisB. bifidumB. longumB. breveSaccharomyces bayanus (used for making wine). Saccharomyces boulardii also find application in medicine as a probiotic.(20,21,22).


The microorganism is very useful for mankind, it can be used for essential products and production. Nowadays microorganisms use in every field to prepare different agriculture, food, and medical product. 


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