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  • Industrial Microbiology

The use of microbes by man to produce beneficial products is an ancient practice that has continued till date. Industrial microbiology is the branch of microbiology that uses microbes to produce industrial products such as drugs, food and chemicals in large quantities. Here, the potentials of microorganisms are harnessed for industrial productions and for other related services in order to increase maximum product yield for higher profit. Some microorganisms are known to produce various useful end-products or metabolites such as acids, alcohols, hormones, enzymes and antimicrobial agents (for example, antibiotics) as part of their metabolic activities. These potentials of microorganisms have been greatly exploited by man, and today, there are many fermentation industries across the globe that produce antibiotics, alcoholic and non alcoholic beverages such as tea, beer and wine through the application of certain microorganisms that actively facilitate the process of fermentation. Industrial microbiologists work in a variety of companies including biochemical industries, biotechnology companies, pharmaceutical companies and food production industries where they exploit the metabolic products of microorganisms (especially their secondary metabolites) to produce a wide variety of useful products (Figure 1).


Most modern brewing processes are computer controlled from the control room with measurements of temperature, gravity, pH and flow rates of materials to the production unit; and this ensures that optimum conditions are maintained at every stage of production. Industrial microbiologists play critical roles in selecting the appropriate microbial strain and growth medium required for enhanced product yield in the industry. They also ensure that the appropriate strains of microbes are always available through strain improvement for industrial productions. Large fermentors or bioreactors are used in beer and wine production plants for the production of quality wine and beer as well as other beverages that are mediated by microbial action. The fermentor which can also be called bioreactors is the vessel within which the fermentation reaction during a Fed batch or batch fermentation process is conducted; and such vessels ensure an even mixture of the microbes or inoculums and other reactants in it in such a way that fermentation proceeds unperturbed. Bioreactors also have channels through which nutrients or substrates can be added as well as openings through which the products can be recovered and wastes retrieved. Industrial fermentors are large vessels that usually range from 10,000 liters to 100,000 liters and even larger, depending on the purpose it is meant to serve (Figure 2). They are fitted with special components such as impellers and spargers that ensure even mixture of the reaction mixture as well as adequate supply of oxygen for the fermentation process.

Figure 1. Process control in an industrial processing plant. Photo courtesy:

Most bioreactors used in industrial microbiology applications are computer-controlled and monitored in order to determine vital parameters of the fermentation process such as pH, buildup of metabolic products and wastes and temperature levels amongst other physical or environmental factors that may affect the fermentation process (Figure 2).

Figure 2. Large-scale industrial fermentors. Photo courtesy:

Industrial microbiologists work on the exploitation of microorganisms in the manufacturing of food and other useful industrial products including but not limited to pharmaceutical products and drugs, chemicals and fuel/energy (for example, biofuels or bioethanol). Industrial microbiology is the application of scientific and engineering principles to the processing of materials by microorganisms including bacteria and fungi to create products that are of economic importance to man. Industrial microbiologists amongst other things ensure the quality control and assurance of products generated from microbial origins. Some groups of microorganisms are of tremendous importance because they are exploited in the production of products such as organic chemicals (for example, citric acid, acetone, methanol, butanol and ethanol), enzymes, amino acids, antibiotics and detergents. Industrial microbiologists are needed by governments, industries, the academia, research institutes or agencies where they proffer regulatory and other supervisory roles as it relates to the harnessing of microbial cells for the production of beneficial products and services. 

  • Environmental Microbiology

Environmental microbiology is the branch of microbiology that studies the role of microorganisms in the maintenance of a healthy, quality, and sustainable environment. It is the study of the composition and physiology of microbial communities in the environment inclusive of the soil, water and air. Environmental microbiologists examine the environment and test it for possible microbial contamination that may pose a public health threat. Microorganisms play tremendous roles in the environment especially as it relates to nutrient recycling, biodegradation of organic matters, and even in bioremediation activities such as the use of specific group of microorganisms to control and remedy the untoward effects of oil spillage in the environment. Bioremediation is simply defined as the biotechnological clean-up of pollutants in the environment. This type of clean-up is usually microbial-based or driven because microbes are used in remedying the polluted environment or soil in order to return it to its natural and unpolluted state. Microbial degradation of pollutants (such as chemical contaminants, pesticides and hydrocarbons) in the environment unlike other physical degradation processes releases environmentally-friendly substances (such as carbon dioxide and water) that have minimal or no negative effect on the ecosystem. Most physical degradation processes though rapid may adversely affect the environment negatively when compared to other biological techniques of degradation that employs microbes for pollutant degradation. Some microorganisms are also used to reduce the microbial loads of industrial wastes and sewages, pesticides, and other heavy metals before their release into the environment. Waste waters from industries and domestic homes are also treated with microbes in like manner (Figure 3).       

Microorganisms have also been used to treat and recycle organic and inorganic wastes. The activities of microorganisms which help to clean-up the environment and keep it safe and free from contaminants are exploited and studied under this very important branch of microbiology. Pseudomonas species, Sphingomonas species, Wolinella species and other facultative anaerobic or microaerophilic bacteria are some of the microorganisms employed for the degradation of pollutants in the environment. The hydrocarbon-degrading activities of microorganisms have helped to contain the oil spills of coastal regions and the open sea areas where oil spillage is common. These microbes have assisted in remediating the ecological damage caused by oil pollutants and other wastes in the environment. An understanding of the impact of microbes in the environment assists environmental microbiologists to prevent environmental problems through adequate detection of the harm.

Figure 3. A waste water treatment plant for the treatment of waste waters from industries and domestic homes. Microorganisms are a critical part of all public and many industrial wastewater treatment processes because of their innate degradative abilities; and microorganisms have the ability to convert waste products such as waste water to nutrients and minerals and other environmentally-friendly products, thus lessening the impact of such wastes on the environment. Photo courtesy:
  • Food Microbiology

Food microbiology is the area of microbiology that studies the interactions of microorganisms and food; how this association can be exploited to produce or process food; and how microbes cause food spoilage. It is the study of microbes that inhabit food and contaminate or spoil it. Food microbiology generally studies beneficial and non-beneficial microbes that impact foodstuffs and beverages from the point of processing, production, storage and usage. Microorganisms cause food spoilage, and they are also exploited in fermentative processes as well to produce a variety of foods such as single cell proteins (SCPs), yoghurt, cheese and beverages (for example tea, wine, beer). Food microbiologists are also concerned with the study of microorganisms known as food-borne pathogens that cause food-borne diseases and food spoilages as well. They are also at the center of preventing food spoilage by developing sustainable ways by which processed foods can be preserved and stored for long period.

Food spoilage is one of the most prevalent microbiological problems facing the food industry globally. This problem has cost the food industry fortunes in terms of the amount of food products that get spoiled by microbes such as bacteria and yeasts or molds on an annual basis. The canning and pasteurization of dairy products such as milk, yoghurt and cheese, and how they can be preserved to avoid microbial contamination and spoilage is also explored in food microbiology. Currently, some foods have probiotics imbedded in them during production, and whole foods have also been produced from microbial origin as well; and this is due to improved techniques in food microbiology, biotechnology and industrial microbiology.

Probiotics are live cultures of bacteria which boost the normal microbial flora of the human gastrointestinal tract (GIT), and thus improve the general health of the gut. Food microbiologists also ensure that all safety and hygienic measures are observed during food production in food related industries. They work in food-related industries where they use their expertise to ensure aseptic techniques during food processing, production and storage. Knowledge of food microbiology acquaints microbiologists of the relationship that exist between microorganisms and food. It also gives emphasis to food safety, food quality, food hygiene and food shelf-life so that adequate measures will be put in place to develop techniques that may contain the spoilage of food especially during food production to food storage. Food microbiologists ensure a safe food supply for mankind; and through appropriate microbiological testing they promptly detect food spoilage organisms and pathogens that cause food borne diseases or infections (Figure 4).   

Food microbiologists test finished food products in order to ensure that imported or exported food products meant for human or animal consumption are actually free of any possible microbial contaminants or chemical poisoning. The ubiquity of microorganisms and their potential to cause food spoilage as well as the possibility of food to transmit disease necessitates the importance and need for adequate and proper microbiological control of food products in order to prevent food spoilage and food borne diseases in human population. When food is not properly cooked, it could serve as route through which food borne diseases and/or pathogens can spread in a defined human population. It is the job of food microbiologists and other public health professionals to ensure that the food that enters the food chain are free from all sources of microbial contamination and potential pathogens that could course food borne diseases.

Figure 4. Food microbiologists analyze food for possible microbial contamination. Photo courtesy:
  • Public Health Microbiology

Public health microbiology is the branch of microbiology that deals with the monitoring, control and spread of infectious diseases and pathogens from community to community, country to country and around the world. Public health microbiologists (referred also as epidemiologists) are disease detectors, and they use their profession, knowledge and skill to improve the quality of health worldwide through timely detection, reporting and prevention of disease outbreak or spread in human populations. They also inspect restaurants, food vendors and food from the food factory to make sure they are pathogen-free and are not sources of food-borne diseases. Public health microbiologists are specialists that utilize key health data to forestall and reverse the spread of an epidemic. They play critical roles in cases of disease outbreak such as in the outbreak of some epidemics including but not limited to ebola virus disease (EVD), cholera, lassa fever and dengue fever to mention but a few. Public health microbiologists share timely, reliable and comparable microbiological or epidemiological statistics with other health professionals including doctors and other government public health specialists in order to efficiently prevent and control communicable diseases in a defined human population.

Sexually transmitted diseases (for example, gonorrhea, syphilis, HIV/AIDS), Ebola virus disease (EVD), lassa fever, tuberculosis (TB), lyme disease, plague, diphtheria, influenza, rabies, hepatitis infection (especially hepatitis B and C), malaria and food borne illnesses are some of the diseases that are of public health importance and must be reported to the authorities for appropriate containment measures. The public health microbiologist play critical role in ensuring that vital data regarding infectious diseases are well shared and reported to the health authorities so that sustainable measures will be taken to contain their further spread especially when an outbreak has already occurred (Figure 5). Research conducted by public health microbiologists is used for the control and prevention of infectious diseases in the community; and they use a wide variety of laboratory techniques which incorporates a multidisciplinary investigation in identifying and characterizing pathogenic microorganisms that directly affect the well being of the general public.

Figure 5. Public health microbiologists collect and analyze health-related data in order to detect, monitor, prevent and contain the outbreak of an infectious disease within a defined human population. Photo courtesy:

Public health microbiologists work in research institutions, the academia, government laboratories, hospitals and in other government and private agencies where there knowledge about the spread of microbes in human population is harnessed and utilized to contain infectious diseases. They also sensitize the general public on possible ways of preventing the contamination and spread of infectious diseases so as to lead a healthier lifestyle.

  • Petroleum Microbiology

Petroleum microbiology studies microbes that metabolize hydrocarbons and how they could be employed in oil prospecting and oil spillage control.Petroleum is a complex mixture of hydrocarbons(i.e., aliphatic and aromatic compounds) and other organic or inorganic constituents such as sulphur, oxygen and carbon. Some microbes metabolize hydrocarbons to generate their energy as well as other growth factors. These microorganisms (for example, Pseudomonas and Homoconis resinae) that degrade hydrocarbons depend solely on crude oil or other refined petroleum products which they degrade to generate nutrient molecules required for their nourishment and growth. For example, the fungus, H. resinae produces more biomass than any other fungi, and this is likely to cause obstruction of pipes in the fuel tank of aircrafts where they colonize. The organism also has the potential to grow between fuel and water and produce suspended solids in fuels, thus giving it the opportunity to cause microbial corrosion in aircraft tanks. Pseudomonas, Arthrobacter, Burkholderia, Sphingomonas, Acinetobacter, Bacillus and Rhodococcus are some bacterial genus that can metabolize and degrade hydrocarbon or organic compounds. However, it is the job of petroleum microbiologists to periodically check aircraft fuels and tanks for possible microbial contamination, and thus ensure that the microbial load of microorganisms are within accepted limits to avoid possible damage to the fuel tanks and other oil installations. In addition, this field of microbiology deals with the use of microbial action or metabolites to control oil spillage and clean up of the environment during oil spillage. This process is known as bioremediation

Microorganisms play significant roles in the oil industry (especially in microbial enhanced oil recovery). They also have the ability to degrade hydrocarbons and clean up the environment especially in oil spillage scenarios as is commonly obtainable in oil rigs and other oil processing and storage facilities (Figure 6). Hydrocarbon contamination of the terrestrial habitat and waterfronts resulting from the activities related to the petrochemical industry is one major environmental problem that is of global concern; and this is largely because hydrocarbons are carcinogenic in nature and some organic pollutants are neurotoxic and thus affect the health of humans, animals and even the aquatic life and the general environment. However, bioremediation and/or biodegradation technology (which employs the metabolic activities of microbes) is currently been exploited for the treatment of hydrocarbon contaminated sites – since it leads to complete mineralization of the hydrocarbons i.e., the transformation of organic compounds including hydrocarbons into simple inorganic molecules such as carbondioxide and water that are environmentally friendly. 

Oil spillage is a common phenomenon that occurs in oil rigs and oil storage or processing facilities. Such development adversely affects both the terrestrial and aquatic environments. However, genetically-engineered microbes have the ability to clean up the affected areas and restore it to its normal and natural condition. Some microorganisms especially the thermophiles withstand several harsh environmental conditions. These organisms are utilized in biodegradation to breakdown crude oil or hydrocarbons in ways that are beneficial to the environment. The biodegradation of hydrocarbons in the environment is primarily carried out by bacteria, yeast and fungi. Some of these microorganisms produce biosurfactants– which are surface active chemical compounds produced by some microbes and which enhances the solubilization and removal of hydrocarbons and other organic compound contaminants in the environment. Microbes are currently being used to prospect for crude oil. The basis for this rationale is because some microbes metabolize hydrocarbons/organic compounds. The use of hydrocarbon-metabolizing microbes as indicators of hydrocarbon utilization gives a clue to the presence or absence of crude oil.

  • Agricultural (Soil) Microbiology

This branch of microbiology which can also be at par with soil microbiology deals with microorganisms that are associated with plants and animals, and how these organisms stimulate plant growth as well as cause diseases in the plants and animals. In agricultural (soil) microbiology, the fertility of the soil as it is being stimulated by microbial activities is also studied, and this branch of microbiology also looks at how soil microorganisms carryout the degradation of organic matter in the soil, and how this activities can impact on the soils fertility. Microorganisms are ubiquitous and they are densely found in the soil where they play important roles as it relates to crop yield and development. A handful of microorganisms that produce antibiotics and other antimicrobial agents that are used in medicine to contain or manage the negative effects of pathogenic microorganisms (i.e., microorganisms that cause disease) are largely found and isolated from the soil. Though there are different categories of microorganisms that cause diseases in plants, microorganisms found in the soil help a lot in nitrogen fixation and many others are used in the compounding of bio-fertilizers which naturally supports the growth of plants (Figure 7). Microorganisms living in the soil affect the plants and crops on the surface in diverse ways especially by helping them acquire vital nutrients required for their proper growth and plentiful harvest. While some microorganisms can cause disease in crops and farm animals, others can be used as bio-pesticides to control the devastating effects of insect pests and weeds in farmlands. Soil (agricultural) microbiologists also study the relationship between microorganisms and plant with the bid of enhancing crop yield and reducing microbial related diseases amongst plants (Figure 8).

Currently, conventional, recombinant DNA technology and genetic engineering techniques are used to improve microbial inoculants which serve as bio-fertilizers or plant growth supplements. These microbial inoculants act by fixing atmospheric nitrogen in order to improve crop yields, and they also serve as plant pest controls by preventing the attack of farm crops by pests. Agricultural microbiologists play tremendous roles in the economy of any nation especially in this current state of global food insecurity. In order to meet up with the current challenges of food insecurity around the globe and provide sustainable food products for the teaming population of the world; microbiologists have manipulated genes and/or proteins that control the architecture and stress resistance of plants (especially to disease and harsh environmental conditions) at the molecular level in order to improve crop productivity and ensure food security across the world. Farmers and agriculturists can improve their crop productivity by using bio-fertilizers which incorporates microbes that help to improve the fertility of the soil. Bio-fertilizers help to unlock nitrogen and phosphorus (which are both vital for plant growth) from the soil; and unlike chemical fertilizers, they are environmentally-friendly and do not adversely affect the soil and the environment. Bio-pesticides, bio-herbicides and bio-insecticides also exist for the control of pests in farmlands, and they have helped to increase productivity in the farmland because they help to keep pests and other crop attackers at bay and under control.  

Figure 7. Application of microorganisms in agricultural practices for sustainable agriculture. Source: Accessed on the 10th February, 2015 from:
Figure 8. Wenbo Ma, a Professor of plant pathology and microbiology at the University of California, Riverside, California. Professor Wenbo’s work is centered on the soya bean plant; and her main research interest is to understand plant-pathogen interactions and how plant’s susceptibility to diseases could be reduced or treated for enhanced crop production. Source: Accessed from the website of University of California, Riverside on the 10th of February, 2015;

The identification of crops and plant species that can withstand stress in any environmental condition as well as crops with good architectural makeup is vital to a sustainable food security worldwide. Certain high-throughput techniques (for example, proteomics and genomics) are being harnessed to identify the genes or proteins responsible for these unique qualities in the plants so that such plants can be propagated to achieve an all-round food security. Agricultural (soil) microbiologists seek to understand how plant-pathogen and soil-pathogen interaction occur, and how this relationship that exists amongst plants, microbes and the soil can be better harnessed to ensure food security.

  • Biotechnology

Biotechnology is simply defined as the use of cellular and biomolecular processes of living organisms especially microbes to produce useful products that are of economic importance. As a biology-based technology, biotechnology harnesses the biological processes of microorganisms at the molecular (genetic) level to produce goods and services that are of economic importance to man and his environment. It is the use of biological processes (for example, microorganisms) to solve practical problems that are beneficial to mankind, plants, animals and the environment. Biotechnology is another vital branch of microbiology that is radically transforming the medical, pharmaceutical and biomedical sciences. This field of biological sciences harnesses the cellular and metabolic profiles or activities of microbes in particular, to improve the quality of life such as in the development and production of novel drugs, vaccines, beverages and food products. Beneficial microorganisms have been genetically-engineered through the application of biotechnology to generate medically important products ranging from drugs/antibiotics/antimicrobials to diagnostics, human therapeutics and hormones. For example, the recombinant human insulin widely used for the treatment of diabetes, a non-infectious disease, is produced based on the application of biotechnology techniques. A handful of food and other industrial products have also been produced through biotechnological applications and other high-throughput techniques.

Through biotechnology, microorganisms can be manipulated at the molecular or genetic level to be more efficient in the production of environmentally friendly products and services. Several high-throughput techniques (for example, gene cloning, gene sequencing, proteomics and genomics) are now available for the manipulation of microorganisms at the molecular level for improved product yield and the development of novel products which have far-reaching economic importance. Biotechnologists work in government agencies, health institutions, research facilities, hospitals and even in educational institutions where their knowledge of microorganisms at the molecular and genetic level are exploited for the synthesis of desired products (Figure 9). Biotechnology is a fast growing field of biological sciences, and microbiologists with practical knowledge of this discipline are highly sourced in many fields of life especially in the pharmaceutical, food, medical and chemical industries. Yogurt, cheese, chocolate, butter, pickles, sauerkraut, soy sauce, food supplements (such as vitamins and amino acids), food thickeners (produced from microbial polysaccharides), alcoholic drinks (for example, beer, whiskeys and wines), sausages and silage for animals are some examples of products of microbial origin or activity. Biotechnology generally involves the industrial application of microbes to produce products that are beneficial to mankind in large quantities.

Figure 9. Biotechnologist work in industries where their skills are used to produce goods and services that are microbially-driven. Photo courtesy:

Biotechnologists play critical roles in the industry during the production of these products especially by identifying the particular microorganisms or strains of microbes that are mainly involved in the production of these industrial products at a larger scale. They also help to maintain proper culture collections of such significant microbial strains for further genetic manipulation, further study and for future use. Once scientists learned about the genetics of microorganisms, and how microbial cells produce proteins; microorganisms could also be altered especially by biotechnologists and made to function in many new or certain and useful ways that are of immense industrial or economic importance. This knowledge rekindled the application of biotechnology to many industries including but not limited to agriculture, medicine, the energy sector, pharmaceutical companies and food processing companies.

  • Medical Microbiology

Medical microbiology is the branch of microbiology that is primarily responsible for the laboratory diagnosis, treatment and prevention of infectious diseases caused by pathogenic microorganisms. Medical microbiologists collaborate effectively with other health professionals and even the patients and their family members in order to provide optimal care of the patient. They also take part in the provision of clinical consultation services both within the hospital and even in the community especially as it relates to pathogenic microorganisms and their prevention and control. Apart from isolating and identifying the causative agents of infectious diseases, medical microbiologists also help the physicians to administer the appropriate therapy owing to the current rapid evolution of drug-resistant microbes. They do this by carrying out antimicrobial susceptibility testing (AST) on representative members of the isolated pathogenic microorganisms using selected antimicrobial agents, so that treatment can be properly guided. Medical microbiology concerns itself with the group or class of microorganisms that cause diseases and other infections in human population. This branch of microbiology specifically deals with pathogenic microorganisms, their life cycle, reproduction, metabolism, physiology, transmission mode and how these important features of diseases and/or pathogen transmission could be exploited to provide solutions to the many diseases that these pathogenic microbes cause in human population. Aside their notable usefulness, some microorganisms known as pathogens cause disease; and it is the task of the medical microbiologist to isolate and identify disease-causing agents from clinically important specimens of patients so that therapy can be properly guided.

Medical microbiologists also contribute to the development of vaccines, diagnostics and other measures that will help to contain the infectious diseases caused by microbes. They work in hospital laboratories, research institutions, in government agencies and even in the academia where they analyze medically important samples in order to isolate and identify the pathogen(s) that is responsible for a particular disease outbreak (Figure 10). They also conduct antimicrobial susceptibility testing (AST) on isolated microbes and give appropriate advice on the treatment course to follow. Medical microbiologists are the eyes of the physicians in the hospital because they carryout AST and other microbiological analysis that guide medical doctors on the choice of antibiotics to use for treatment. Microbiological research as carried out by medical microbiologists will lead to the development of novel diagnostic tools to improve on the prompt detection of pathogenic strains including those that are multidrug resistant. Medical microbiologists work in the hospitals, government agencies, pharmaceutical companies and academic institutions as aforesaid. They collect and analyze specimens from a wide variety of body sites; and they distinguish pathogens from non-pathogens (i.e., beneficial microorganisms) and generate practicable data that help physicians and other healthcare providers to make the correct diagnosis and therapeutic choices for sick patients.

Figure 10. Illustration of a medical microbiologist performing microbiological analysis on clinical samples of patients. Photo courtesy:
  • Pharmaceutical Microbiology

Pharmaceutical microbiology is the branch of microbiology that focuses on all aspects of pharmacy especially as it relates to the manufacture, safety and quality control of pharmaceuticals such as drugs and vaccines. Microbiological applications are tremendously applied in the pharmaceutical industry to produce a wide range of products including but not limited to hormones, antibiotics, water for injections, vaccines and steroids which are used for the treatment and management of both infectious and non-communicable diseases in human and animal populations. Irrespective of the suffering of patients due to infectious diseases caused by pathogenic microorganisms, healthcare delivery has tremendously improved worldwide owing to the availability of effective medicines and vaccines with which to treat and prevent these diseases from spreading and causing more havoc. Pharmaceutical companies around the world are investing heavily in research and development (R&D); and they are also in high demand for pharmaceutical microbiologists due to the relevance of this branch of microbiology in the manufacture of safe, effective and good-quality biopharmaceuticals.

Pharmaceutical microbiology also deals with the controlling of microorganisms that cause spoilage of pharmaceutical products. This area of microbiology is also keenly interested in harnessing the metabolic activities of microorganisms to develop novel and potent medicines and other pharmaceuticals for the health sector. This branch of microbiology is a burgeoning area in the biological sciences due to its importance to not just the health and pharmaceutical sector, but also the central role that it plays in ensuring the improvement of world health and disease prevention. The production of novel drugs from herbal plants and other natural products are also the subject of pharmaceutical microbiologists.           

  • Water Microbiology

Water microbiology is the branch of microbiology that ensures that the water supply to homes, industries, towns and local communitiesare of good quality and free from water-borne pathogens such as Escherichia coli and Vibrio cholerae. It studies the biological aspects of microorganisms that dwell in water, and how their metabolic activities can impact the environment. Water microbiologists work in water distribution and purification companies where they analyze water from reservoirs and river sources to check for their quality and microbial load before distribution to homes and industries (Figure 11). They also ensure that sewage and other industrial wastes are properly treated before release into water ways and that they are not potential causes of water-borne diseases. Another aspect of water microbiology is aquatic microbiology which deals with the study of microorganisms and how their metabolic activities could be exploited to improve the health of man and animals in the fresh, marine and estuarine habitat. Water borne diseases such as cholera and dysentery are amongst the child killer diseases in the developing world; and these infections are prevalent in places where environmental sanitation is poor. It is mainly the task of the water microbiologists to ensure that the water distribution channels are free from water-borne pathogens; and that water meant for domestic use and for other human purposes such as in the industry for manufacturing are free from pathogenic microorganisms. Escherichia coli is an indicator of water contamination aside other water borne pathogens. Its presence in water meant for domestic usage especially drinking water and other sources of water is an indication of possible faecal contamination either from emptying of sewage into the water ways or from direct human defaecation in the water body.  

Figure 11. Water microbiologists examine and culture water samples for the detection and isolation of water-borne pathogens in order to prevent the outbreak and spread of waterborne diseases. Photo courtesy:
  • Immunology

Immunology is an aspect of microbiology that concerns itself with the study of the immune system in man, animals and in other living organisms. The immune system is made up of cells, tissues and organs that work together in a cooperative manner to protect human host’s from or against the invasion of foreign substances (antigens) and pathogenic microorganisms. They also help to eliminate these foreign molecules and thus minimize their deleterious effects in the body. Immunologists study the immune system (composed of innate and acquired immunity) to better understand it and proffer practical explanation as to how the immune system could be exploited to contain and prevent some infectious diseases and their causative agents. They also work in pharmaceutical companies and other health related industry where they develop strong and sustainable preventive measures against the acquisition of infections for example, through the production of potent vaccines and medications for various infectious diseases. Vaccines are vital tools in clinical medicine, and they are mainly used to prevent infectious disease occurrence and spread in susceptible human population through the process of immunization/vaccination. Immunologists work in the government, healthcare sector, research institutions and even in the academia where their knowledge of the body’s immune system are brought to bear to unravel some of the mysteries of infectious diseases especially in human and animal populations.       

  • Molecular Microbiology and Genetics

Molecular microbiology concerns itself with an understanding of the biosynthesis of informational molecules of life such as DNA, RNA and proteins; and how these biomolecules or macromolecules of life can be genetically manipulated and harnessed for the benefit of man and his environment. Microbiologists in this area of molecular microbiology and genetics focus on the nature of genetic manipulation and how it regulates the development and function of cells and organisms. The use and manipulation of the genetic components of microorganisms has been very helpful in understanding gene function in humans, animals and other living organisms. Microbial genetics play important role in applied microbiology by helping to produce new microbial strains that are more efficient in synthesizing useful products that are of economic importance. With the ever growing and improving molecular tools and high-throughput techniques (for example, polymerase chain reaction, PCR and gene sequencing) in molecular microbiology, microbiologists can detect pathogens more rapidly and accurately from clinical and/or environmental samples based on the genetic signatures of the organisms (Figure 12). 

Generally, this aspect of microbiology studies the genetic makeup of microorganisms (DNA and RNA inclusive), their heredity patterns and variations that occur amongst members of the same species. Knowledge of the genetic makeup of microorganisms especially those that are multidrug resistant in nature (for example, bacteria producing extended spectrum beta-lactamases and metallo beta-lactamases) will help to provide clues as to how the emergence and spread of disease-causing microbes particularly those that are drug resistant could be monitored and contained. Since the genome is mainly the control center of the cell, molecular microbiologists (in whose duty it is to study microbes at the molecular level) play critical role in helping the medical community to unravel the genetic basis of some infectious and non-infectious diseases that affect humanity, thereby proffering sustainable solutions to their treatment, cure and eradication.       

Figure 12. A microbiologists carrying out experiment using molecular techniques. Photo courtesy:

Further reading

Brooks G.F., Butel J.S and Morse S.A (2004). Medical Microbiology, 23rd edition. McGraw Hill Publishers. USA. Pp. 248-260.

Madigan M.T., Martinko J.M., Dunlap P.V and Clark D.P (2009). Brock Biology of microorganisms. 12th edition. Pearson Benjamin Cummings Publishers. USA. Pp.795-796.

Nester E.W, Anderson D.G, Roberts C.E and Nester M.T (2009). Microbiology: A Human Perspective. Sixth edition. McGraw-Hill Companies, Inc, New York, USA.

Prescott L.M., Harley J.P and Klein D.A (2005). Microbiology. 6th ed. McGraw Hill Publishers, USA. Pp. 296-299.

Singleton P and Sainsbury D (1995). Dictionary of microbiology and molecular biology, 3d ed. New York: John Wiley and Sons.

Slonczewski J.L, Foster J.W and Gillen K.M (2011). Microbiology: An Evolving Science. Second edition. W.W. Norton and Company, Inc, New York, USA.

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