project on microbes in human welfare

8/10/2019 project on microbes in human welfare

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MICROBES IN HUMAN WELFARE

Presented by Mark Evans


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What are microbes?

A microorganism(from the Greek: , mikrs, "small" and, organisms, "organism"; also spelled micro-organism, micro organismor microrganism) or microbeis amicroscopic organism that comprises either a single cell(unicellular), cell clusters., or multicellular relatively complex

organisms. The study of microorganisms is called microbiology, asubject that began with Anton van Leeuwenhoek's discovery ofmicroorganisms in 1675, using a microscope of his own design.Microorganisms are very diverse; they include bacteria, fungi,algae, and protozoa; microscopic plants (green algae); andanimals such as rotifers and planarians. Some microbiologists

also include viruses, but others consider these as nonliving. Mostmicroorganisms are unicellular (single-celled), but this is notuniversal, since some multicellular organisms are microscopic,while some unicellular protists and bacteria, like Thiomargaritanamibiensis, are macroscopic and visible to the naked eye.


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Microorganisms live in all parts of the biospherewhere there is liquid water, including soil, hot springs,

on the ocean floor, high in the atmosphere and deepinside rocks within the Earth's crust. Microorganismsare critical to nutrient recycling in ecosystems as theyact as decomposers. As some microorganisms can fixnitrogen, they are a vital part of the nitrogen cycle,

and recent studies indicate that airborne microbesmay play a role in precipitation and weather.

Microbes are also exploited by people inbiotechnology, both in traditional food and beveragepreparation, and in modern technologies based on

genetic engineering. However, pathogenic microbesare harmful, since they invade and grow within otherorganisms, causing diseases that kill humans, otheranimals and plants. But they have a lot of uses too.Lets discuss about some of them.


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A little description

Microorganisms are vital to humans and theenvironment, as they participate in the Earth'selement cycles such as the carbon cycle and

nitrogen cycle, as well as fulfilling other vitalroles in virtually all ecosystems, such as recyclingother organisms' dead remains and wasteproducts through decomposition. Microbes also

have an important place in most higher-ordermulticellular organisms as symbionts. Manyblame the failure of Biosphere 2 on an improperbalance of microbes.


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Uses in food

Microorganisms are used in brewing, winemaking, baking, pickling andother food-making processes.

They are also used to control the fermentation process in the productionof cultured dairy products such as yogurt and cheese. The cultures alsoprovide flavour and aroma, and inhibit undesirable organisms.

Fermentationin food processing typically is the conversion ofcarbohydrates to alcohols and carbon dioxide or organic acids usingyeasts, bacteria, or a combination thereof, under anaerobic conditions.Fermentation in simple terms is the chemical conversion of sugars intoethanol. The science of fermentation is also known as zymology, orzymurgy.

Fermentation usually implies that the action of microorganisms isdesirable, and the process is used to produce alcoholic beverages suchas wine, beer, and cider. Fermentation is also employed in the leaveningof bread (CO2produced by yeast activity), and for preservationtechniques to produce lactic acid in sour foods such as sauerkraut, drysausages, kimchi and yogurt, or vinegar (acetic acid) for use in picklingfoods.


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Uses in water treatment

Specially-cultured microbes are used in the biological treatment of sewage andindustrial waste effluent, a process known as bioaugmentation.Bioaugmentationis the introduction of a group of natural microbial strains or agenetically engineered variant to treat contaminated soil or water.

Usually the steps involve studying the indigenous varieties present in thelocation to determine if biostimulation is possible. If the indigenous variety do

not have the metabolic capability to perform the remediation process,exogenous varieties with such sophisticated pathways are introduced.

Bioaugmentation is commonly used in municipal wastewater treatment torestart activated sludge bioreactors. Most cultures available contain a researchbased consortium of Microbial cultures, containing all necessary microorganisms(B. licheniformis, B. thurengensis, P. polymyxa, B. sterothemophilus, Penicilliumsp., Aspergillus sp., Flavobacterium, Arthrobacter, Pseudomonas, Streptomyces,

Saccaromyces, Triphoderma, etc.). Whereas activated sludge systems aregenerally based on microorganisms like bacteria, protozoa, nematodes, rotifersand fungi capable to degrade bio degradable organic matter.


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Uses in energy

Microbes are used in fermentation to produce ethanol, and in biogas reactors toproduce methane. Scientists are researching the use of algae to produce liquidfuels, and bacteria to convert various forms of agricultural and urban waste intousable fuels.Ethanol fermentation, also referred to as alcoholic fermentation,is a biological process in which sugars such as glucose, fructose, and sucrose areconverted into cellular energy and thereby produce ethanol and carbon dioxide

as metabolic waste products. Because yeasts perform this conversion in theabsence of oxygen, ethanol fermentation is classified as anaerobic.

Ethanol fermentation occurs in the production of alcoholic beverages andethanol fuel, and in the rising of bread dough.Cellulosic ethanolis a biofuelproduced from wood, grasses, or the non-edible parts of plants.

It is a type of biofuel produced from lignocellulose, a structural material thatcomprises much of the mass of plants. Lignocellulose is composed mainly of

cellulose, hemicellulose and lignin. Corn stover, switchgrass, miscanthus,woodchips and the byproducts of lawn and tree maintenance are some of themore popular cellulosic materials for ethanol production. Production of ethanolfrom lignocellulose has the advantage of abundant and diverse raw materialcompared to sources like corn and cane sugars, but requires a greater amount ofprocessing to make the sugar monomers available to the microorganisms thatare typically used to produce ethanol by fermentation.


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Algae fuelis an alternative to fossil fuel that uses algae as its source of natural deposits.Several companies and government agencies are funding efforts to reduce capital andoperating costs and make algae fuel production commercially viable. Harvested algae,like fossil fuel, release CO2when burnt but unlike fossil fuel the CO2is taken out of theatmosphere by the growing algae.

High oil prices, competing demands between foods and other biofuel sources, and theworld food crisis, have ignited interest in algaculture (farming algae) for makingvegetable oil, biodiesel, bioethanol, biogasoline, biomethanol, biobutanol and otherbiofuels, using land that is not suitable for agriculture. Among algal fuels' attractivecharacteristics: they can be grown with minimal impact on fresh water resources, can beproduced using ocean and wastewater, and are biodegradable and relatively harmless tothe environment if spilled. Algae cost more per unit mass (as of 2010, food grade algae

costs ~$5000/tonne), due to high capital and operating costs, yet are claimed to yieldbetween 10 and 100 times more fuel per unit area than other second-generation biofuelcrops. One biofuels company has claimed that algae can produce more oil in an area thesize of a two car garage than a football field of soybeans, because almost the entire algalorganism can use sunlight to produce lipids, or oil. The United States Department ofEnergy estimates that if algae fuel replaced all the petroleum fuel in the United States, itwould require 15,000 square miles (39,000 km2) which is only 0.42% of the U.S. map, orabout half of the land area of Maine. This is less than 17the area of corn harvested in the

United States in 2000. However, these claims remain unrealized, commercially.According to the head of the Algal Biomass Organization algae fuel can reach priceparity with oil in 2018 if granted production tax credits.


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Use in production of

chemicals, enzymes etc. Many microbes are used for commercial and industrialproduction of chemicals, enzymes and other bioactivemolecules.Examples of organic acid produced include

Acetic acid: Produced by the bacteriumAcetobacter acetiand other acetic acid bacteria (AAB)Acetic acid bacteria(AAB) are bacteria that derive their energy from theoxidation of ethanol to acetic acid during fermentation.They are Gram-negative, aerobic, rod-shaped bacteria.They are not to be confused with the genusAcetobacterium,

which are anaerobic homoacetogenic facultativeautotrophs and can reduce carbon dioxide to produceacetic acid, for example,Acetobacterium woodii.


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Butyric acid(butanoic acid): Produced by thebacterium Clostridium butyricumClostridiumbutyricumis a strictly anaerobic endospore-formingGram-positive butyric acid producing bacillussubsisting by means of fermentation using anintracellularly accumulated amylopectin-like -polyglucan (granulose) as a substrate. It isuncommonly reported as a human pathogen andwidely used as a probiotic in Asia (particularly Japan).C. butyricumis a soil inhabitant in various parts of theworld, has been cultured from the stool of healthychildren and adults, and is common in soured milk

and cheeses.


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Lactic acid: Lactobacillusand others commonly called as lacticacid bacteria (LAB) The lactic acid bacteria (LAB)comprise a

clade of Gram-positive, low-GC, acid-tolerant, generally non-sporulating, non-respiring rod or cocci that are associated bytheir common metabolic and physiological characteristics. Thesebacteria, usually found in decomposing plants and lacticproducts, produce lactic acid as the major metabolic end-productof carbohydrate fermentation. This trait has, throughout history,

linked LAB with food fermentations, as acidification inhibits thegrowth of spoilage agents. Proteinaceous bacteriocins areproduced by several LAB strains and provide an additional hurdlefor spoilage and pathogenic microorganisms. Furthermore, lacticacid and other metabolic products contribute to the organolepticand textural profile of a food item. The industrial importance of

the LAB is further evinced by their generally recognized as safe(GRAS) status, due to their ubiquitous appearance in food andtheir contribution to the healthy microflora of human mucosalsurfaces.


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Citric acid: Produced by the fungusAspergillusniger Aspergillusnigeris a fungus and one of themost common species of the genusAspergillus. Itcauses a disease called black mold on certain

fruits and vegetables such as grapes, onions, andpeanuts, and is a common contaminant of food.It is ubiquitous in soil and is commonly reportedfrom indoor environments, where its blackcolonies can be confused with those ofStachybotrys(species of which have also beencalled "black mould").


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Microbes are used for preparation of bioactivemolecules and enzymes. Streptokinase produced bythe bacterium Streptococcusand modified bygenetic engineering is used as a clot buster forremoving clots from the blood vessels of patients

who have undergone myocardial infarctions leadingto heart attack.

Cyclosporin A is a bioactive molecule used as animmunosuppressive agent in organ transplantation

Stains produced by the yeast Monascus purpureusis

commercialised as blood cholesterol loweringagents which acts by competitively inhibiting theenzyme responsible for synthesis of cholesterol.


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Uses in science

Microbes are also essential tools in biotechnology,biochemistry, genetics, and molecular biology. Theyeasts (Saccharomyces cerevisiae) and fission yeast(Schizosaccharomyces pombe) are important modelorganisms in science, since they are simpleeukaryotes that can be grown rapidly in largenumbers and are easily manipulated. They areparticularly valuable in genetics, genomics and

proteomics. Microbes can be harnessed for usessuch as creating steroids and treating skin diseases.Scientists are also considering using microbes forliving fuel cells, and as a solution for pollution.


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Uses in warfare

In the Middle Ages, diseased corpses were thrown into castles during siegesusing catapults or other siege engines. Individuals near the corpses wereexposed to the deadly pathogen and were likely to spread that pathogen toothers.Biological warfare(also known as germ warfare) is the use of biologicaltoxins or infectious agents such as bacteria, viruses, and fungi with intent to killor incapacitate humans, animals or plants as an act of war. Biological weapons

(often termed "bio-weapons" or "bio-agents") are living organisms or replicatingentities (viruses) that reproduce or replicate within their host victims.Entomological (insect) warfare is also considered a type of biological warfare.

Biological weapons may be employed in various ways to gain a strategic ortactical advantage over an adversary, either by threats or by actualdeployments. Like some of the chemical weapons, biological weapons may alsobe useful as area denial weapons. These agents may be lethal or non-lethal, andmay be targeted against a single individual, a group of people, or even an entire

population. They may be developed, acquired, stockpiled or deployed by nationstates or by non-national groups. In the latter case, or if a nation-state uses itclandestinely, it may also be considered bioterrorism.


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Importance in human health

Microorganisms can form an endosymbiotic relationship with other, largerorganisms. For example, the bacteria that live within the human digestivesystem contribute to gut immunity, synthesise vitamins such as folic acid andbiotin, and ferment complex indigestible carbohydrates. The humanmicrobiome(or human microbiota) is the aggregate of microorganisms thatreside on the surface and in deep layers of skin, in the saliva and oral mucosa, in

the conjunctiva, and in the gastrointestinal tracts. They include bacteria, fungi,and archaea. Some of these organisms perform tasks that are useful for thehuman host. However, the majority have no known beneficial or harmful effect.Those that are expected to be present, and that under normal circumstances donot cause disease, but instead participate in maintaining health, are deemedmembers of the normal flora. Though widely known as "microflora", this is, intechnical terms, a misnomer, since the word root "flora" pertains to plants, andbiota refers to the total collection of organisms in a particular ecosystem.

Recently, the more appropriate term "microbiota" is applied, though its use hasnot eclipsed the entrenched use and recognition of "flora" with regard tobacteria and other microorganisms. Both terms are being used in differentliterature. Studies in 2009 questioned whether the decline in biota (includingmicrofauna) as a result of human intervention might impede human health


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Importance in ecology

Microbes are critical to the processes of decomposition requiredto cycle nitrogen and other elements back to the natural world.Decomposition(or rotting) is the process by which organicsubstances are broken down into simpler forms of matter. Theprocess is essential for recycling the finite matter that occupies

physical space in the biome. Bodies of living organisms begin todecompose shortly after death. Although no two organismsdecompose in the same way, they all undergo the samesequential stages of decomposition. The science which studiesdecomposition is generally referred to as taphonomyfrom theGreek word taphos, meaning tomb.

One can differentiate abioticfrom biotic decomposition(biodegradation). The former means "degradation of a substanceby chemical or physical processes, eg hydrolysis). The latter onemeans "the metabolic breakdown of materials into simplercomponents by living organisms",typically by microorganisms.


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Hygiene

Hygiene is the avoidance of infection

or food spoiling by eliminating microorganisms from thesurroundings. As microorganisms, in particular bacteria, arefound virtually everywhere, the levels of harmful

microorganisms can be reduced to acceptable levels.However, in some cases, it is required that an object orsubstance be completely sterile, i.e. devoid of all livingentities and viruses. A good example of this is a hypodermicneedle.

In food preparation microorganisms are reduced by

preservation methods (such as the addition of vinegar),clean utensils used in preparation, short storage periods, orby cool temperatures. If complete sterility is needed, thetwo most common methods are irradiation and the use ofan autoclave, which resembles a pressure cooker.


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There are several methods for investigating the level of hygienein a sample of food, drinking water, equipment, etc. Water

samples can be filtrated through an extremely fine filter. Thisfilter is then placed in a nutrient medium. Microorganisms on thefilter then grow to form a visible colony. Harmful microorganismscan be detected in food by placing a sample in a nutrient brothdesigned to enrich the organisms in question. Various methods,such as selective media or PCR, can then be used for detection.The hygiene of hard surfaces, such as cooking pots, can be testedby touching them with a solid piece of nutrient medium and thenallowing the microorganisms to grow on it.

There are no conditions where all microorganisms would grow,and therefore often several different methods are needed. Forexample, a food sample might be analyzed on three differentnutrient mediums designed to indicate the presence of "total"bacteria (conditions where many, but not all, bacteria grow),molds (conditions where the growth of bacteria is prevented by,e.g., antibiotics) and coliform bacteria (these indicate a sewagecontamination).


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