Read this essay to learn about Microbiology. After reading this essay you will learn about: 1. Introduction to Microbiology 2. Eras of Microbiology 3. Some 20th Century Highlights in Microbiology 4. Branches of Microbiology 5. Scope and Future of Microbiology and 6. Modern Microbiology.
Essay on Microbiology Content:
- Essay on Introduction to Microbiology
- Essay on the Eras of Microbiology
- Essay on Some 20th Century Highlights in Microbiology
- Essay on Branches of Microbiology
- Essay on the Scope and Future of Microbiology
- Essay on the Modern Microbiology
Essay # 1. Meaning of Microbiology:
Microbiology is a branch of biology that deals with microorganisms (often upto a diameter of 1000 µ ) and their effects on other living organisms. It derives its name from the union of three greek words: mikros (= small), bios (= life bearing); and logos (= study).
It ia a multi-disciplinary science of microorganisms and the prefix ‘micro’ generally refers to an object small enough so that microscopic examination is required for detailed visualization. Thus it is the scientific study of microorganisms, including a diverse group of simple life forms like protozoa, algae, molds, bacteria and viruses.
Microbiology is concerned with the structure, function, classification and ways of controlling and using their activities. The earlier works done by Antony Van Leauwenhoek (1632 – 1723), and later in 19th century by Louis Pasteur (1822- 1893) and Robert Koch (1843-1910) etc. laid the foundations of this subject.
Essay # 2. Eras of Microbiology:
1. Era of Speculation (5000 BC to 1675):
Prior to Hippocrates (412 B.C.) some Biblical and other historical records often talked of the death tolls that some disease had taken. And Hippocrates seems to have been the first observer to document an Influenza epidemic in the year 412 B.C. Epidemics of plague have been recorded in China since 224 B.C.
Major Plague epidemics occurred in 540 AD in Egypt, reached Constantinopole in 542, and spread to Europe and Asia in the following decade; and was called the Plague of Lustinion named after the emperor of Brezantine Empire from 527 to 565 A.D.
One of the most notorious of the plague epidemics consumed 14th century Europe. It began in the Volga River Basin in 1345, travelled north through Europe and reached England in 1348, and finally Russia in 1351. It was called as The Great Dying, Magna Mortalis or The Black Death, claimed around one-third to one half the population of Europe and an estimated 40 million deaths worldwide.
It was probably the concept of quarantine (from the Italian quarentina, meaning forty, supposed to be based on the number of days Christ spent in the wilderness) was instituted then. Though the infected individuals were kept isolated from others, the reservoir of the disease causing microbes (Rats) and the rat fleas (the vector) were allowed to roam freely.
The proposed remedies were also interesting and included burning incense sticks, dipping handkerchiefs in aromatic oils, ringing church bells, firing canons, wearing magical figures and bathing in human urine etc. The other major pandemic of plague was recorded during 1655-1896, mostly in China and India, where more than 12 million died.
It was in 1894 that Yersin and Kitasato described the causative agent, now known as Yersinia pestis. And, it wasn’t until 1897 that the mode of transmission was conclusively identified.
During early 1940s Syphilis spread throughout Europe. It was on this ailment Paul Ehrlich, in the first decade of the 20th century focused his search for the “magic bullet”. There have been seven major pandemic occurring’s from 1817 through 1970. Smallpox alone is estimated to have killed more than 100 million people worldwide.
In the late 18th century the work of Edward Jenner, who developed a vaccine from the similar virus of cowpox, paved the way for the control of this deadly disease. Infact, the term Vaccine was born from the Latin word for cow, vacca, based on Jenner’s work.
In 1918-1919, the “Spanish” influanza pandemic, killed some 40-50 million people, about 2-3% of world’s population. It attacked the very young and very old, taking advantage of their frail immune systems. It also spread across five continents.
Though considerable work was being done in the field of bacteriology, the advances in the field of virology had to wait for the development of the electron microscope by Belgian Physicist Marton (1934).
In the late 17th century a slow yet methodical pursuit began as a new chapter in humanity’s understanding of the hitherto unseen and unknown world. As per WHO report, in 2003 alone, more than 11 million people died of infectious diseases including AIDS, tuberculosis and Malaria and of them half of them in Africa.
2. Era of Observation (1675 to Mid 19th Century):
The unknown, transmissible substance, Virus (Latin for poison) had always puzzled humanity. Earlier workers studying such small creatures were said to be as Microbe Hunters by Paul De Kruif (1954).
Scientific and methodological understanding of bacteria had already started in this era and the advanced versions of Light and advent of electron microscope started new horizons for the classical microbiology. It is at times seen from 1675 to mid19th century.
3. Era of Cultivation (Mid 19th Century to Early 20th Century):
Although a period of over 150 years of observations and discoveries by many early microbiologists had contributed a lot to the understanding of this discipline, still the cause of infectious diseases was completely unknown till mid 19th century. In 1857, Pasteur, the chemist with a microscope turned beet sugar into alcohol.
Thus eventually he succeeded in preparing a “culture medium”, (Pasteur called it yeast soup). Infact the lack of suitable means to obtain pure cultures was a major impediment to the development of the “Germ Theory of Disease”. Pasteur thus entered into the field of fermentation and was perhaps the first to associate the growth of specific microbes with the production of specific fermentation products.
It was in the year 1865 that the “Germ Theory of Disease” was inaugurated. After fermentation Pasteur was called to look the cause of silkworm disease in South France, and after observing the diseased eggs and other details he wrote: “If I can be permitted this antithesis, the role of infinitely small being appeared to me infinitely large, either as a cause of various diseases, especially contagious diseases, or as contributors to the decomposition and to the return to the atmosphere of everything which has lived”. (Lechevalier and Solotorovsky, 1965).
Although the prevailing spontaneous generation influenced Pasteur’s work, but he believed that microbes did not arise spontaneously, as the air exposure had failed many of the earlier efforts to demonstrate such things. Later Tyndall, the physicist, and Pasteur postulated that specks of dust carried microbes. This was an experiment which did it all, and is now known as famous swan-neck flask experiment.
In 1877, Fedinand Cohn described the spores of Bacillus subtilis and their heat-resisting properties. Thus the joint efforts of Pasteur, Tyndall and Cohn finally eroded the concept of spontaneous generation. Robert Koch is believed to have used a solid surface (a potato slice) to grow microorganism.
Loeffler and Graffky working in Koch’s lab, devised the streak method whereby they would use a fine wire or needle to streak potato with an organism. Koch, being an amateur photographer, also produced photomicrographs while working on ‘Anthrax’ and used gelatin for this purpose.
But gelatin proved to be a wrong choice as it melted at temperatures above 15°C and thus could not be incubated at the optimal temperatures for the growth of many organisms, they were trying to study. It was in 1882, when Frau Angelina Hesse, the wife of a graduate student in Koch’s lab, suggested agar-agar, came as a final solution.
At 1-1.5%, its properties were well-studied and suited for use in microbiology having a melting point of 100°C and a setting point of less than 45°C. This enabled the incubation of cultures to anything below 100°C.
This technique revolutionized cultural bacteriology and enabled the great advancement of the subject during the last two decades of the 19th century.
Later the germ theory of disease was advanced by Koch and also demonstrated the association between specific microbes and specific diseases, and showed that there was an external source of the germs and to get the disease, the germs must gain entrance into the victim. Koch was also invited to address the endemic Cholera problem.
He had concluded that the same slightly curved rod in every victim (and not present in Healthier individuals) present in polluted water around huts was the cause of the disease. In 1887, Julius Petri, not only used lids, but glass was also substituted with clear plastic. Also the grid was added to counting chambers.
Chantemesse and Widal, 1887, prepared the first differential medium using glucose and lactose peptone water to differentiate E.coli from Salmonella typhii. After that a Japanese bacteriologist Kitasato developed a test for indole production to further aid in the differentiation of these species. In 1892, Wurtz of Paris introduced the use of indicators in the medium to detect acid production.
Pasteur later developed the preparations from the causative agents of chicken cholera showing the alteration of the virulence and the development of a vaccine produced by laboratory manipulation. This is how Pasteur, ‘Father of Microbiology’ had opened the field of preventive medicine. Pasteur and his colleagues, Emile Roux, and Chamber-land, had further successes using attenuated anthrax bacilli.
Essay # 3. Some 20th Century Highlights in Microbiology:
The 1900’s witnessed tremendous advances on several fronts: microbial metabolism, microbial genetics and molecular biology, antimicrobial therapies, and development of selective and differential culture media and virology, just to name a few.
Also the art of microbial toxonomy moved from a purely morphological basis to one based on metabolic characteistics. The reclassification of species (with molecular methods in use) allowed grouping of organisms according to their genetic make up.
The genetic materials’s role became useful in studies aimed at understanding bacterial variation and antibiotic resistance. The processes of bacterial transformation and mutation were the basis for determining that all genetic information of cells is coded for by DNA.
The year 1928 saw the discovery of Penicillin by Alexander Flemming. Howard Florey associated (driven by the intense need of Second World War), purified it in 1940 and it became commercially available. It also promoted the work and search for other such antimicrobial weapons produced by soil microorganisms.
Later, Streptomycin was discovered and other broad-spectrum antibiotics followed by the development of semisynthetic antibiotics.
The 1920-40s witnessed the development of .many of the selective media used today, as well as techniques for the isolation of anaerobic organisms. In 1953 Watson and Crick, published the double helix model for DNA. In 1983, DNA became a useful tool when Karry Mullis invented the technique of Polymerase Chain Reaction (PCR)
London County Council Laboratory Services in 1950, led to the commercial development of dehydrated media.
The virology progressed due to several reasons made possible by:
(a) The use of fertile eggs as a method for the cultivation of a virus.
(b) The UV-microscopy (developed by Barnard) gave the first view of the elementary bodies of a number of viruses.
(c) The development of tissue culture techniques in the 1920’s and 30’s and
(d) The development of the electron microscope by Marton in 1934.
In 1954, the development of the monolayer technique and that of using cytopathic effect for viral detection led to the availability of live virus vaccines. Since then the development of antiviral chemotherapies has been a thrust area of researches in microbiology. In 1995 the entire genome sequencing was completed for Haemophilus influezae.
Essay # 4. Branches of Microbiology:
Microbiology is a mutidisciplinary subject as the microbes are not only playing useful role in nature through their links in bio-geochemical cycles, symbiotic relationship, in maintaining soil fertility, in bio-remediation, also as plant pathogens, microbes in biotechnology and as amodel organisms for biochemical molecular and genetic processes but are also providing homogenous experimental material relatively quickly. As a result of their link to several branches of science many branches of microbiology can be identified (and are still growing……).
Some of the established branches are as follows:
1. Industrial Microbiology:
It encompasses the uses of a variety of microbes in industrial processes. Initially they were being used for industrial fermentation and waste water treatment. As today industry is linked to biotechnology, several new industrial applications have been found for a variety of microbes.
It is sometimes also studied as microbial biotechnology and is the application of scientific and engineering principles to the processing of materials by microorganisms (such as bacteria, fungi, algae, protozoa and viruses) or plant and animal cells to create useful products or services. Areas of industrial microbiology include quality assurance for the food, pharmaceutical, and chemical industries.
2. Medical Microbiology:
This branch of microbiology deals with the scientific study of pathogenic microbes, the diseases they cause, their mode of survival in environment and their hosts (including life-cycle); their diagnosis, prevention and treatment.
In fact, as early as Varo and Columella in the first century BC had postulated that the diseases were caused by invisible beings (animalia minuta). Von Plenciz (1762) had put forth the idea that each disease was caused by a separate agent.
It covers a variety of topics where microbes are responsible for causing diseases of skin and eye infections, pneumonia (by bacteria), several sexually transmitted diseases (STD’s), minor arthropod diseases, gastrointestinal infections including infections from drinking cow milk harbouing certain pathogenic bacteria and their remedies etc.
3. Agricultural Microbiology:
This branch deals with microbes having an impact on agriculture and food chains. Both, the harmful (microbes causing plant diseases) as well as useful microbes (e.g., N2 fixing microbes, use of microbes in bio-fertilizers etc.) are studied under this branch.
Certain raminants also carry a mixture of complex bacteria that enable the animal to extract sufficient nutrient from a diet of grasses. Future research in microbial ecology will help to determine in preserving a balance in mirobial communities that favour agriculture.
4. Environmental Microbiology:
In the late 1800’s, and early 19th century Sergei Winogradsky, a Russian Mineralogist, pioneered the field of microbial autotrophs, and initiated the field of Environmental Microbiology. This branch includes the study of composition and physiology of microbial communities of the environment.
It also deals with the activities of microbial entities, their interactions among themselves and with maroorganisms. Adhesion, biofilm formation, global element cycles, biogeochemical processes and microbial life in extremes of environment or unexplored environs all fall in its preview.
5. Food and Dairy Microbiology:
As the microorganisms are ubiquitous (present almost everywhere) food and milk are no exceptions. Hence the microbes are studied from the viewpoint that they (e.g., Bacteria, Yeasts, molds etc.) can either act as spoilage microorganisms or pathogenic microorganisms.
And thus how they can cause spoilage, prevent spoilage through fermentation or can be the cause of human illness, all comes under the realm of this branch of microbiology. It is a thrust area of microbiology these days, as more and more food items are being packaged (including milk and its products) for later use.
The UN convention on Biological Diversity defined Biotechnology as: any technological application that uses biological systems, living organisms, or derivatives thereof to make or modify products or processes for specific use. Bio-engineering, including recombinant genetic technology of the 21st century is the science upon which all biotechnological applications are based.
It combines disciplines like genetics, molecular biology, biochemistry, food sciences, mechanical engineering, chemical engineering, microbiology, cell biology and all are interrelated to electronics, information technology and robotics.
The current science of bacteriology includes the study of both domains of prokaryotic cells (the Bacteria, and Eucarya). But recently due to out-break of molecular techniques applied to phylogeny of life, another group of prokaryotes was defined and informally named,” archaebacteria (it has now been renamed as Archaea) and included in the study of bacteriology”.
It is the study of viruses, complexes of nucleic acids and proteins that have the capacity for replication in animal, plant or bacterial cells. To replicate, the viruses use their genomes (DNA or RNA) or of the host cells and cause changes in cells, particularly its antigenicity and may cause several diseases in plants and animals is all covered under this branch.
9. Soil Microbiology:
This branch deals with the biota that inhabits the soil and the processes they mediate. As the soil is a complex environment, colonized by an immense variety of microorganisms, the soil microbiology focuses on soil viruses, bacteria, actinomycetes, fungi and protozoa, but traditionally it has also included investigations of soil animals such as nematodes, mites and other arthropods.
Modem soil microbiology represents an integration of microbiology with the concepts of soil science, chemistry and ecology to understand the functions of microorganism in the soil environment.
10. Sewage Microbiology:
This branch deals with the study of microbial flora of various types of sewage. The sewage may, depending upon source, can contain harmless (E. coli and other coli forms) to potential pathogens including enterococci, Vibrio cholerae, Salmonella typhi, etc. This branch studies their qualitative as well as quantitative details and ways to combat them following various treatment processes.
It deals with the study of various fungi. Fungi are eukaryotic organisms and around 300 species are shown to be pathogenic for man. It studies their morphology, taxonomy, biosystematics, distribution, propagation, and several mycotic diseases they cause including hypersensitivity, mycotoxicoses, mycetismus and other infections and their remedies.
It is a sub-discipline of botany, and deals with the scientific study of algae. As many species are single celled and microscopic (e.g. Phytoplankton and micro algae); yet others are multicellular (some growing) very large as seaweeds such as Kelp and Sargassum they are also studied in microbiology.
It also covers aspects like cyanobacteria (blue-green algae) and other microscopic forms occurring as symbionts in lichens.
Earlier much in use, this branch is the study of protozoa (motile and heterotrophic) protists. Protozoa-despite their small size and unicellularness offer complex and unique biological features. They also serve as experimental models in a variety of cellular, molecular, biochemical and ecological researches.
One of the applied sub-branches of this old branch is medical protozoology (covering protozoa infecting humans). It covers life-cycles, morphological features, host-parasite interactions, geographical distributions, reservoir hosts, method of transmission and control, pathology, immunological aspects, diagnosis and remedies are all included in it.
14. Aquatic Microbiology:
It covers the study of microorganisms and their activities in natural water. As the natural waters include lakes, ponds, streams, rivers, estuaries and oceans, it initially started covering all of them.
But due to the growth of the subject several other branches have also been recognized and are as follows:
(a) Marine microbiology
(b) Estuarine microbiology
(c) Groundwater microbiology, and
(d) Deep-sub-surface microbiology
The aquatic microbiology deals with the variability of aquatic habitat and rapid changes in characteristics and associated microbial component. The microbial activity and biomass measurement studies are performed to follow microbial functions in water ecosystems. Also the balance between N, P, O and H is studied in lakes, eutrophic systems, and streams etc.
15. Marine Microbiology:
As marine environment is the largest part of the biosphere, being about 97-98% of all the water on earth, efforts are being made to study seas, especially deep seas (and their microbial functioning), as 75% of the ocean is below 1000 m depth (and is constantly cold at about 3°C on an average).
The oceanic explorations like Challenger expedition and Galathea expedition were among the initial efforts to critically explore microbial aspects of the deep seas and the nature of psychrophilic bacteria. Barotolerant bacteria are among the unique fauna of deep oceans.
As the most of the earlier work on seas and oceans remains confined to the near-shore and estuarine marine environments, the interest is growing in the off-shore and pelagic ocean microbiology.
16. Estuarine Microbiology:
It deals with the rapid variations in the physicochemical properties in estuaries leading to the establishment of unique microbial communities. This branch also undertakes the study of epiphytic microbial communities of estuarine plants, its biomass, temperature, salinity etc. And as great fluctuations are observed in estuarine environments, so are the varieties of microbial groups including sulphur bacteria, iron bacteria and heterotrophs etc.
17. Groundwater Microbiology:
Earlier the groundwater was assumed to be sterile, as very early studies indicated a decrease in microbes with increasing depths. But the microbiology of groundwater has become an important branch due to increased pressure on groundwater, ever increasing contamination and presence of microbes in deep waters.
18. Deep Sub-Surface microbiology:
This is a recent branch of microbiology and addresses deep aquifers (hundreds of meters below surface). It attempts to study the role of microorganisms in influencing the petroleum, sulphur and other drilling companies and vice-versa.
It is the study of those invisible microorganisms (less than 1 mm in size) which are present in air. It also covers monitoring, distribution and diversity of airborne microorganisms in indoor and outdoor environments and especially the ones causing breathing trouble and diseases.
20. Geo-Chemical Microbiology:
It covers the role of a variety of microbes in hydrocarbon processing in formation of coal, gases and minerals. It also tells us to employ microbes for recovery of minerals from low grade ores.
21. Bio-Degradation Microbiology:
The microbial degradation of chemicals in the environment is an important route for removal of these compounds. This branch deals with the details of the degradation of hydrocarbons, lignins, cellulose, hemicellulose, polyaromatic hydrocarbons (PAH’s) and pesticides including organophosphates, chlorinated hydrocarbons, dithioates and carbonates.
It deals with the microbes in the outer space (or the extraterrestrial space) but all these microbes were originated on earth. In other words, the space microbiology is called exomicrobiology.
It .is the study of our protection from foreign macromolecules or invading microorganisms and our responses to them. These invaders include viruses, bacteria, protozoa or even larger parasites. How our first line of defense (e.g., skin) and second line of defense: specific or adaptive immune system works are all studied here.
Parasitology is the study of parasites, their hosts and the relationship between them. This being a multi-disciplinary branch uses inputs of various techniques from fields such as cell biology, bioinformatics, biochemistry, molecular biology, immunology, genetics, evolution and ecology.
It is the study of the factors affecting health and illness of populations and use of preventive medicines in order to cure such diseases. It is derived from the term epi = upon, among; demos = people, district, and logos = study meaning “what is upon the people”.
This indicates that it applies to human only. Hippocrates, the famous Greek Physician is sometimes said to have coined the term epidemic (for diseases that are seen at some times but not others); and endemic (for diseases usually found in some places but not in others.)
26. Avian Microbiology:
Microbiology and Veterinary science are complimentary fields in the medical maintenance and treatment of birds. Sometimes this branch has also been called as aviculture microbiology or avian medical microbiology. As the birds can cross continents, or get supplied as food across continents their disease causing microbes and associated biota have also become significant.
27. Veterinary Microbiology:
Veterinary microbiology is concerned with microbial (bacteria, fungal and viral,) diseases of domesticated animals (e.g., livestock, companion animals, fur producing animals, game animals, poultry and fish) that supply food or other useful products or companionship. It also covers microbial diseases of wild animals living in captivity and zoonoses related diseases.
28. Pharmaceutical Microbiology:
Sometimes seen as a part of industrial microbiology, this branch is responsible for screening several drugs (parental and oral drugs) following strict measures for measuring microbiological testing in order to validate certain compounds to standard protocols.
29. Oral Microbiology:
It is a modern branch of microbiology where all the microbes associated with major dental diseases (e.g., caries and periodontal diseases) are studied. It also covers all the resident oral bacteria and host details.
30. Evolutionary Microbiology:
This branch deals with all phases of the systematics of prokaryotes, yeasts and yeast like organisms, including taxonomy, nomenclature, identification, phylogeny, evolution, biodiversity, characterization and culture preservation etc. It also covers all aspects related to the evolution of all micro-organisms, including the protists (as protozoa and algae).
31. Microbial Physiology:
It is an interesting branch of microbiology concerned with the structure, function and relationships of microorganisms, with particular emphasis on how microbes respond in response to changes in environment.
32. Microbial Genetics:
Microbial genetics is a subject area within biotechnology and genetic engineering. It studies the genetics of very small (micro) organisms. It also encompasses the study of the genotype of microbial species and also the expression system in the form of phenotypes.
33. Probiotic and Prebiotic Microbiology:
Probiotics and prebiotics have long been appreciated for their positive influences on gut health. The prebiotics include the non-digestible food ingredients that selectively stimulate the growth and/or activity of beneficial microorganisms in people’s colon. And the probiotics are live microorganisms (in most cases bacteria) that are similar to the microorganisms found in the human gut.
They are also termed as “friendly or good bacteria”. The probiotics are available to consumers mainly in the form of dietary supplements and food. Due to growing consciousness about health, they are nowadays also being used as complementary and alternate medicine (CAM).
One widely used definition of probiotics, is the one given by World Health Organization (WHO) and Food and Agriculture Organization (FAO) of the United Nations; is that,” Probiotics are live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host.”
Essay # 5. Scope and Future of Microbiology:
The microbes not only need to be understood as causative agents of diseases but are also useful to us as contributors in food production, antibiotic manufacture, vaccine development and environmental management.
Recently the subject had also allowed us to explore and control the following diseases; Foot and mouth disease, Asian Bird Flu, SARS (Severe Acute Respiratory Syndrome), West Nile Virus, and Monkey-pox.
We are now also exploring more Prions related diseases causing a type of amyloid diseases (characterized by normal brain protein being altered and changing into fibres); at times called as: Transmissible Spongiform Encephalopathy (TCS).
Some famous examples include:
Creutzfeldt-Jakob disease in humans (CJD), Bovine Spongiform Encephalopathy (BSE) also known as mad-cow disease, chronic wasting disease (CWD) in deer and elk Kuri in human Feline spongiform Encephalopathy (FSE), and Transmissible mink Encephalopathy (TME). The interest is growing in various zoonotic diseases (of animals that can pass to humans) due to their close proximity of rearing or habitation.
Due to undergoing environmental changes, global warming and related climate changes, various mathematical models are trying to understand the impact of these factors on disease causing microbes of their respective hosts. Immunoparasitology has helped us in the past to understand various pathogens.
But due to a use of wide variety of invasions and immune evasion mechanisms used by various parasites, the nature keeps posing greater challenges for epidemiologists. As a result several genome mapping programmes are underway for disease causing protozoa and helminths (e.g., L. major, P. falciparum, and T. gondii etc.).
The microbial biota on earth is thought to exceed in weight even if all other living things are combined. This is the same as eloquently argued by palaeontologist Stephen Jay Gould (1996), that the 21st century will be the era of the microbes.
As the bacteria alone account for 50% of the biomass of carbon and over 90% of the biomass of Nitrogen and phosphorus combined on our planet, such claims seem to be true. The future microbiology is already an integrative microbiology incorporating inputs from microbial physiology, microbial genetics, microbial ecology and microbial pathogenesis using tools and dialects of various sub disciplines.
The use of microbes in nanotechnology has brought microbiology to engineering and physics. And recent discoveries indicate that microbes also play roles in determining animal behaviour, bringing microbiology to the realm of psychology. Hence the 21st century microbiology is already an integrative science with lots of challenges and benefits to reap.
Essay # 6. Modern Microbiology:
Modern microbiology reaches into many fields of humans including the development of pharmaceutical products, the use of quality-control and dairy product production, the control of disease-causing microorganisms in water, and the industrial applications of microorganisms.
Microorganisms are used to produce vitamins, amino acids, enzymes, and growth supplements. They manufacture many foods including fermented dairy products (sour cream, yogurt, and buttermilk), as well as other fermented foods such as pickles, sauerkraut, breads, and alcoholic beverages.
One of the major areas of applied microbiology is biotechnology. In this discipline microorganisms are used as living factories to produce pharmaceuticals that otherwise could not be manufactured.
These substances include the human hormone insulin, the antiviral substance interferon, numerous blood-clotting factors and clot dissolving enzymes, and a number of bacteria can be engineered to increase plant resistance to insects and frost and biotechnology will represent a major application of microorganisms in the next century.