Microorganisms play an important role in our life: helps us to digest our food, decompose wastes and participate in various cycles. They are diverse and have adapted to inhabit different environments including extreme conditions, such as hot vents under the ocean to the ice caps; known as extremophiles. There are more microorganisms present in us than there are cells, and the various microorganisms are bacteria, viruses, fungi and protozoa. Many people link microorganisms as death and diseases causing agents; also usually compared to dirt. Although some microorganisms are responsible for causing diseases, most microorganisms’ original hosts are not the human body so are not pathogenic, but commensal. This essay will discuss the numerous beneficial microorganisms that carry out processes in biotechnology, agriculture, industries and environment; necessary to sustain life.

Firstly, essential uses of microorganisms can be seen in the environment, as they play a vital role in many of the nutrient cycles. For instance, carbon fixation during the carbon cycle by autotrophic bacteria, such as cyanobacteria, synthesize organic molecule using CO2 from the atmosphere to be used by other organisms and release oxygen for our consumption. In addition, microorganisms are vital participants of the food chain since they act as decomposers; breaking down dead organisms and organic materials and releasing minerals for uptake by living organisms and CO2 back into the atmosphere to be used by photosynthetic organisms. Microorganisms, known as methanogens, influence the carbon cycle by converting CO2 in their cells to methane and releasing it into atmosphere; thus increasing methane concentration whereas methanothrophs consume methane from the atmosphere, leading to a decrease in the greenhouse gas and global warming (Prescott, 1999).

Involvement of microorganisms in the nitrogen cycle demonstrates that they are not just beneficial for humans, but are significant to plants as well; especially diazotrophs. Plants and diazotrophs have developed a symbiotic relationship, for example, Rhizobium present in the nodules on legume roots, fixes nitrogen enabling the plant to flourish in nitrogen-deficient grounds. Microorganisms are crucial for all three steps of nitrogen cycle: firstly, Nitrosomonas and Nitrosococcus convert ammonium ions to nitrite and Nitrobacter convert nitrite to nitrate during nitrification; secondly, during denitrification Pseudomonas denitrificans reduces nitrate to nitrogen gas and thirdly nitrogen fixation, with the diazotrophs reducing nitrogen from the air into ammonia which are utilized by the plants to synthesize DNA and amino acid. Another microorganism interacting with the plants are mycorrhizal fungi, which forms a symbiotic relationship with plant roots. This association is beneficial for plant as fungal hyphae increases surface area enabling the plant roots to absorb more nutrients; also advantageous to fungi since they gain sugars produced by plants during photosynthesis (Atlas Bartha, 1998).

Moreover, microorganisms digest harmful chemicals, such as pollutants and chemical wastes produced by the industry through a process known as bioremediation; thus protecting the environment and human health. In this process, microorganisms grow over a solid substrate to form a biofilm, through which the fluid containing the contaminants are poured through, so that the enzymes produced by the microorganism can degrade the contaminant and the resulting fluid is non-toxic. In a similar process microorganisms aid sewage water treatment: primary treatment, such as screening, results in sludge which is digested by anaerobic microorganisms; during secondary treatment microorganisms enable floc formation, biodegradation and neutralization of toxins when passed over the microbial films, e.g., Geobacter sulfurreducens purifies contaminated water by precipitating metals such as uranium (Hofkin, 2010).

Applications of microorganisms in the food industry, mainly in the production of dairy products are another example where microorganisms are beneficial to humans. Lactobacillus bulgaricus and Streptococcus thermophilus converts lactose in milk into lactic acid causing the milk to coagulate, during fermentation (reduction and oxidation of organic molecules), and form yoghurt in the process. Furthermore, probiotic yoghurt with live bacteria’s is also produced nowadays, to maintain the balance of microbial flora in our gut and prevent the growth of pathogens. Fermentation of milk by lactic acid bacteria also causes the milk to coagulate and form curd; then additional organisms is added to form the various cheeses, such as Penicillium camemberti to produce Camembert. Another example is the addition of Streptococcus lactis and Leuconostoc citrovorum to cream during fermentation to produce lactic acid, which causes thickening of the cream, and gives rise to the flavour that is attributed to sour cream. Furthermore, microbes such as yeasts which help us in the process of bread making, alcohol production and food preservation are also part of our diet. For example, marmite and vegemite are made from “spent brewer’s yeast” and are rich in vitamins. Additionally, Fusarium graminearum, a type of fungus has been developed into meat substitute for human consumption. The success of the food industry is partially due to the careful selection and addition of beneficial microorganisms, leading to a variety of cultured food for a wide range of people (Hofkin, 2010).

Understanding microbe’s genetics has enabled us to use microorganisms in genetic-engineering techniques, such as gene cloning, and has given numerous benefits to the biotechnological industry. Microorganisms, such as bacteria, viruses and bacteriophages, act as cloning vectors to transfer specific sequence of gene, into the plasmid of the bacterial cell using restriction enzymes. The purpose of the restriction enzyme is to bind to the inverted palindrome in both chromosomal and vector DNA; thus cleaving the DNA and producing sticky ends. The sticky ends of both DNA are joined together by DNA ligase producing a recombinant DNA; used to transform the bacteria host cell. The bacteria can be induced to produce the protein which these genes encode as the vector is replicated and divides to produce new cells. Since the vector contains a selectable marker, maybe coding for antibiotic resistant gene, the bacterial cells which has taken up the recombinant DNA can be identified. Proteins from recombinant technology can be used to produce medicines, synthetic vaccines and other vital substances, such as insulin for diabetic individuals. Application of microorganisms in the medical industry is beneficial to human health, but also to the economy because huge amount of medicines produced using microorganisms, such as insulin from E.coli, lowers the cost of production (Hofkin, 2010).

Retrovirus, acts as a vector in gene therapy to treat ADA deficiency; patient’s ADA-deficient lymphocytes is cultured in the laboratory and infected with the retrovirus that contains the normal ADA gene, creating a recombinant retroviruses. During the replication of the retrovirus, its own DNA containing the normal ADA gene is inserted into the host’s DNA causing the patient’s lymphocytes to synthesize ADA (Hofkin, 2010).

Another application of recombinant techniques in the biotechnology industry, is the production of heat stable enzymes from thermophiles; organisms that live in an extremely hot environment. For instance, DNA polymerase produced from Thermus aquaticus and Thermococcus litoralis is used in the PCR and DNA fingerprinting, has enabled tracing of the fate of genes in plant and animal populations and improved gathering of evidence at crime scenes. Similarly, another enzyme, which breaks down lignin, obtained from Phanerochaete chrysosporium is used in the paper industry to bleach paper without the production of dioxin; thus preventing pollution (Hofkin, 2010).

Application of genetic-engineering techniques in agriculture is the production of transgenic plants, using Agrobacterium tumefaciens to introduce cloned genes, such as resistant to environmental stress. This is achieved by replacing the genes in T-DNA of Ti plasmid that causes the crown gall tumour with the gene of interest and a selectable marker gene, usually resistance to kanamycin. The T-DNA is then incorporated into the plant genome when exposed to A. tumefaciens, and these cells grown in a medium containing kanamycin and carbenicillin. Transgenic plants have led to the development of biodegradable plastics and medical products such as production of vaccines from altering transgenic plants (Prescott, 1999).

Another example of benefits of microorganism in agriculture is their use as biological pest control, for example, Bacillus thuringiensis produce Bt-toxin which is lethal for insects if ingested, but non-pathogenic to humans and other animals; Bt-toxin gene is genetically engineered into crops to increase their yield. Some viruses are also microbial biopesticides, baculoviruses, and they specifically target caterpillars, by releasing nucleocaspsids – causes the insect to die – when ingested; therefore they are efficient pest control without huge environmental side-effects (Hofkin, 2010).

Usually microorganisms are associated with causing cancer, but recent developments have highlighted they could be used in treating cancer. William B. Coley showed that the tumors relapsed when cancer patients were injected with various pathogens, such as Coley’s toxin. Recent research findings have revealed that Mycobacterium bovis can be used in treating bladder cancer, as the BCG strain in microorganism kills the tumor (Chakrabarty, 2003). Similarly, recent development has suggested that Bdellovibrio bacteriovorus could be used as antibiotics, since they ingest E.coli, Salmonella spp. and other disease causing gram-negative bacteria, without affecting the humans (Rendulic et al., 2004).

An additional important application of microorganism in medical industry is using bacteriophage to make antibiotics for curing anthrax. Schuch and his colleagues (2002) obtained enzyme, PlyG, from the bacteriophage; its function is to lyse the bacterial wall of B. anthracis. Their research revealed that PlyG was a strong lytic enzyme, as even when applied externally they still lysed the B. anthracis strains; and that 80% of B. anthracis infected mice was saved when injected with the enzyme.

The World of Microorganisms

Microorganisms, also known as microbes, are tiny living organisms that cannot be seen with the naked eye. They exist everywhere on Earth, from the depths of the oceans to the highest peaks. Despite their small size, microorganisms play a crucial role in the functioning of ecosystems and have a significant impact on human life.

Types of Microorganisms

There are several types of microorganisms, including bacteria, viruses, fungi, and protozoa. Each type has unique characteristics and functions:

1. Bacteria: Bacteria are single-celled organisms that can be found in various environments, such as soil, water, and even inside the human body. Some bacteria are beneficial, contributing to nutrient cycling and human health, while others can cause diseases.

2. Viruses: Viruses are smaller than bacteria and are not considered living organisms. They can only replicate inside host cells and can cause a range of diseases, such as the common cold, flu, and COVID-19.

3. Fungi: Fungi are multicellular organisms that include molds, yeasts, and mushrooms. They can be found in diverse habitats and have important roles in decomposition, nutrient cycling, and food production. Some fungi can also cause infections in humans.

4. Protozoa: Protozoa are single-celled organisms that live in water and soil. They play a vital role in nutrient recycling and are an essential part of aquatic food chains.

Importance of Microorganisms

Microorganisms have a wide range of roles and impacts on the environment and human life:

1. Nutrient Cycling: Microbes are essential for decomposing organic matter, recycling nutrients, and maintaining ecosystem balance. They break down dead plants and animals, releasing nutrients back into the environment.

2. Food Production: Microorganisms are used in various food production processes, such as fermentation. They are responsible for the production of yogurt, cheese, bread, and alcoholic beverages.

3. Medicine: Many antibiotics and vaccines are derived from microorganisms. They are also used in the production of insulin and other pharmaceuticals.

4. Environmental Cleanup: Certain microorganisms have the ability to break down pollutants and toxins, contributing to the cleanup of polluted environments.

5. Research and Biotechnology: Microorganisms are extensively studied for their genetic, metabolic, and physiological characteristics. They are used in research laboratories and biotechnology industries for various purposes, including the production of enzymes and biofuels.

Conclusion

Microorganisms are an integral part of the world we live in. Despite their small size, they have a significant impact on the environment and human life. Understanding their diversity, functions, and interactions is crucial for the preservation of ecosystems and the development of beneficial applications in various fields.