Microbial Biotechnology Part Two PPT 32 PDF

Addis Ababa Science and Technology University Department of Biotechnology COURSE TITLE: MICROBIAL BIOTECHNOLOGY COURSE NO. - Bot3105 Part Two CREDIT HRS-3 Million Yohannes Senior Lecturer  Chapter 5: Applicati`on of microbes in food bi...

Addis Ababa Science and Technology University Department of Biotechnology COURSE TITLE: MICROBIAL BIOTECHNOLOGY COURSE NO. - Bot3105 Part Two CREDIT HRS-3 Million Yohannes Senior Lecturer  Chapter 5: Applicati`on of microbes in food biotechnology DAIRY PRODUCTS DAIRY PRODUCTS. Dairy products are derived from milk, the secretion of the mammary glands of mammals, usually cows (bovine), sheep, goats, buffalo, mare, camel, or yak. Most dairy products originate from bovine milk and, to a lesser extent, sheep and goat milk. As milk contains approximately 80 to 90 percent water, it is prone to undesirable microbial growth with concomitant product deterioration. To prevent this problem from occurring, and to ensure a longer shelf life, milk is processed to form different products such as ice cream, cheese, milk powders, yogurt, butter, lactose, and anhydrous milk fat (also known as butteroil). Milk can be separated into a cream fraction and a skim milk fraction by a centrifugation technique called separation. This process concentrates the fat present in the milk into the cream phase, leaving a skim or partially skimmed phase with much lower fat content.  DAIRY PRODUCTS Milk processing applies different preservation techniques to allow for longer storage of dairy products. Milk powders are produced by concentration to remove some of the water, followed by atomization into a fine mist and drying at high temperatures. Heat and dehydration (water removal) are employed to give a long shelf life for milk powders. Ice cream is a dairy product preserved by the action of freezing. Yogurt and cheese are both fermented products. A bacterial culture is used to inoculate milk, for which the primary function is to lower the pH from 6.7 to 4.2 for yogurt and in the range 4.6 to 6.0 for most cheese varieties. The bacterial cultures also assist in breaking down proteins and fats in the milk product to develop some of the flavor. The preserving function of added bacterial culture is to compete with unwanted pathogens for nutrients. Thus cheese and yogurt are preserved by dehydration, acidification, and competition with pathogens for survival in the product.  Heat Treatment of Milk For food safety reasons, milk is often heat-treated prior to consumption or further processing. The most common heat treatments are holding at 162°F (72°C) for 15 seconds, called pasteurization, or at 145°F (63°C) for 30 minutes, called batch pasteurization. Both of these treatments have similar effects on killing undesirable microorganisms in milk. The treatment is sufficient to destroy two indicator organisms, Mycobacterium tuberculosis and Coxiella burnetti. Another common heat treatment is to hold milk at 284°F (140°C) under pressure for 2 to 3 seconds, producing ultra high temperature (UHT) milk. This milk is essentially sterile and can be packaged in cardboard containers and stored at room temperature for up to six months with little microbial-induced deterioration.. An alternative to preserving milk by heat pasteurization is high- pressure processing, where pressures of around 300–600 MPa are employed to rupture the membranes of pathogens and denature enzymes that cause deterioration in milk quality. Diary products  5.2 Fermented food and single cell protein Food microbioilogy Food microbiology focuses on those microorganisms that reproduce in food and cause food spoilage. Understanding of physical factors that affect microbes is important in the process of controlling microbial growth or inhibition of microbes. Safety standards in food processing is also important. Food has he chance to come in contact to humans or animals before consumption. There is a higher possibility for pathogenic microorganisms that caused disease to contaminate food and cause disease when consumed. Viruses such as Norovirus, Hepatitis, and Rotavirus may contaminate food causing disease to humans. Contamination of food from human faeces and vomiting caused by viral food born illness. Regarding bacteria, Salmonella, E.coli, Vibrio, Shigella all causes food born diseases. Cooking food kills bacteria (10000:1), the vegetative forms.  Food microbioilogy Spores of Clostridium perferinges, Bacillus cerus, Clostridium botulinum all survive food pasteurization temperature. Double washing of foods and vegetables used to reduce surface bacteria (100 to 1 reduction). When bacteria multiply to number (107) per gram of food, the food becomes slimy and is considered to be spoiled and has off-flavor and odor to be judged as spoiled. Yeasts. Larger than bacteria in size. Yeasts do not cause food born illness or diseases. They are used in food processing like in Tella, Tej, Beer, Enjera and wine preparation. Like molds, yeasts have the ability to grow at low temperature and low water activity on stored food causing food spoilage. Molds. Molds are fungi that appear as cottony, powdery on food surfaces. They may be white or gray or highly colored. Most of the molds cause spoilage problem. E.g mold on cheese, fruits, Enjera, Vegetables, bread and the like. Its growth alter favor and texture of food. Some molds are beneficial by producing good flavor to food products. E.g Cheese (Roquefort cheese). Some molds are harmful and produce toxin called AFLATOXIN which is carcinogenic compound  Food fermentation Fermentation is a natural process through which microorganisms like yeast and bacteria convert foods such as starch and sugar — into alcohol or acids. The alcohol or acids act as a natural preservative and give fermented foods a distinct test and tartness. Fermentation also promotes the growth of beneficial bacteria, known as probiotics. Probiotics have been shown to improve immune function as well as digestive and heart health. Adding fermented foods to your diet may benefit your overall well-being. The fermented products are more nutritious, energy rich, tasty, and have good flavor. Raw substrates include milk, meat, fish, vegetables, fruits, seeds, beans and e.t.c Food fermentation Fermented Foods Fermented Foods Food groups. Fermented food products. Diary Ergo, Ayib or cheese, butter products milk, kefir, acidophilus milk. Meat products Sausage, pickled meat, Salami, e.t.c Fruits and Pickled fruits, vegetables, vegetables Kimchi, e.t.c Beverages Tella, Tej, Borde, Shamita, Beer, Wine.  Food fermentation Microorganisms can be used by natural contamination traditionally or by adding starter from previous fermentation. In industrial fermentation, pure or mixed starter culture can be used. There are 12 genera of bacteria included in group of Lactic acid bacteria (LAB). LAB converts carbohydrate into lactic acid and fermented food products like Yoghurt. 5 among 12 genera are Lactococcus, Leuconostoc, Pediococcus, Streptococcus, and Lactobacillus which hare used as starter culture. The LAB bacteria are Gram positive, non-motile, Non-sporing, cocci, rod shape Catalase and oxidase negative. Fastidious and acid tolerant. Lactic acid is the sole major product.  Food fermentation Acetobacter. Acetobacter is used to produce acid from alcohol. it is gram negative aerobic rod occurring as single cell, pairs or chains. It is either motile or non-motile. Naturally found in fruits, wine, sugar cane and beer. It is catalase positive and obligate aerobe. It converts ethanol into acetic acid. It also converts lactic acid into carbon dioxide and water. It grows well at 25oC ----- 30oC. Yeasts. Many yeasts and mold are important in fermentation and used for different purpose. Most of them involved in spoilage of foods and mycotoxin production by molds. They are genetically modified to improve desirable characteristics. Yeasts is unicellular and over 1500 species known. Molds. Genera of Aspergillus, Penicillium and few from Rhizophus and mucor have been used for beneficial purpose. Selection of mold that do not produce mycotoxin is important. Fermented oriental foods to produce sake, soy sause, miso. E.g Aspergillus oryzae. Aspergillus niger is used to produce citric acid and gluconic acid from sucrose.  Food fermentation Diary Microbiology (Ergo and Ayib). Milk (balanced diet) is an excellent growth medium for microbes. I is sterile until it reaches milk ducts in cows udder unless ill. Bacteria from container, equipment, handlers enter milk. LAB which is Lactobacilliaceae and streptococcaceae are the most abundant normal flora of milk. These are divided into two groups. 1. Homofermentative:- produce only lactic acid CH3CHOHCOOH) from carbohydrates. 2. Heterofermentative:- carbohydrates are converted into acetic acid, ethanol, CO2 and lactic acid. Other bacterial genera include micrococcus, staphylococcus, Pseudomonos, Bacillus and E.Coli. E.coli is undesirable in its presence showing contamination by pathogen related to sanitation conditions. Fermentation carried out by mesophiles, thermophiles, LAB, Yeast and molds. Mesophiles ------------- Butter milk, cultures milk. Thermophiles -------------yoghurt, Bulgarian milk.  Food fermentation Therapeutic LAB ------------- Biograde, Biofighurt, acidophilus milk. Yeast ------------- lactic fermentation which can give kefir. Molds lacatic acid fermentation gives Villi. Mesophiles. Lactobacillus species and lactococcus lactis culture sub species diacetylactis convert milk citrate into diacetyl which gives special buttery flavor to finished products. Therapeutic of fermented products. Health benefits Stabilize bowl microflora. Antimicrobial properties. Lower serum cholesterol. Anti-cancer activity. Anti-tumer compounds. These foods may reduce heart disease risk and aid digestion, immunity, and weight loss.  Food preservation. Food preservation is the process of handling food in a way to stop or cut down spoilage to prevent food born illness without hampering texture, nutritional value and flavor. This prevents growth of bacteria, fungi and other microbes. It prolongs shelf life of food. Food preservation methods categorized as Chemical based ---addition of inhibitory chemicals e.g organic acids. Physical based --- heating, freezing, smoking drying, radiation, low aw. Microbiological based inhibition---- addition of substance such as bacteriocins to foods to control food pathogens. Physical based methods. Filtration, heating (to destroy vegetative cells and spore), pasteurization (heating to kill pathogens), sterilization (i.e above 100oc for some period of time). Freezing (refrigerator), chilling (short term process preservation in cold storage). Irradiation (exposure to long waves UV rays), Drying. Chemical preservation. Addition of food additives to inhibit microbes (e.g benzoic acid SO2, acetic acid). They affect cells like in affecting cell membrane. It is also addition of antioxidants to hinder oxidation of unsaturated fats.  Chapter 6: Application of microbes in agro-biotechnology 6.1 Bio-fertilizers and Feeds A healthy agricultural production depends on various factors like soil quality, water, fertilizers, skilled labor, and more. Fertilizer is the most crucial thing that influences agricultural production. A fertilizer is a kind of chemical or natural substance that is helpful in crop production. However, to achieve quick agricultural yields we usually use chemical fertilizers which are very responsive to biofertilizers but the chemical fertilizers are not eco-friendly as biofertilizers.  Bio-fertilizers and Feeds The use of chemical or synthetic fertilizers is common practice to increase crop yields. These synthetic fertilizers have their own disadvantages. These includes high cost and environmental pollution. Biofertilizers are biologically active products origin of microbial inoculants of bacteria, fungi or algae or in combination which may help biological nitrogen fixation for the benefits of plants. They are microbial inoculants or commercial preparation of microorganisms which increase the nitrogen and phosphorous level and increase plant growth.  Bio-fertilizers and Feeds Biofertilizers broadly includes the following categories. Symbiotic nitrogen fixers (eg Rhizobium spp and Bradyrhizobiumspp) Asymbiotic nitrogen fixers ( egAzobacter) Phosphate solubilising bacteria Thiobacillus and Bacillus) Organic fertilizers ( manure , animal dung, urine, sewage, crop residues, and urban garbages). Benefits of biofertilizers Low cost and easy to produce. Fertility of the soil is increased year after year. Environmental friendly ( free from environmental pollution). Increase crop productivity. Increase physic chemical properties of the soil , soil texture, and water holding capacity. Limitations of biofertilizers Cannot meet the total needs of the plants for nutrient supply. Cannot produce spectacular results.  Animal Feed Feed, food grown or developed for livestock and poultry. Modern feeds are produced by carefully selecting and blending ingredients to provide highly nutritional diets that both maintain the health of the animals and increase the quality of such end products as meat, milk, or eggs. Ongoing improvements in animal diets have resulted from research, experimentation, and chemical analysis by agricultural scientists. Animals in general require the same nutrients as humans. Some feeds, such as pasture grasses, hay and silage crops, and certain cereal grains, are grown specifically for animals. Other feeds, such as sugar beet pulp, brewers’ grains, and pineapple bran, are by-products that remain after a food crop has been processed for human use. Surplus food crops, such as wheat, other cereals, fruits, vegetables, and roots, may also be fed to animals.  6.2 Bio-controls and Biocides Bio-control (Biological control) Biological control is a method of restricting effects of harmful animals, pathogens and plants using other useful organisms, e.g. microorganisms, insects and plants that inhibit the harmful organisms. The method takes advantage of basic ecological interactions between organisms, such as predation, parasitism, pathogenicity and competition. Today, biological control is used primarily for controlling pests in crop cultivation. Advantages of biological control are that no artificial substances are added, and that pathogens / animals that develop resistance against biological control agents are rare. Biological control is an important component of integrated pest management.  Different types of biological control There are four basic types of biological control: 1. Natural biological control: The service carried out by resident natural enemies of pests and pathogens without human involvement. 2. Conservation biological control: Directed stimulation of resident natural enemies to enhance their control of pests and pathogens. 3. Augmentative biological control: Addition of propagated bio- control agents, temporarily increasing their population densities in a targeted area. 4. Classical biological control: Addition of new bio-control agents for proliferation and long-term establishment.  Biocides Biocides are groups of chemicals often referred to as non- agricultural pesticides. It is a chemical compound or biological product used to kill, control the growth of, or repel a specific organism. Biocides are usually active substances or mixtures containing one or more active substances, put up in the form in which they are supplied to the user. Pesticides used to eliminate pests in agriculture are normally not considered to belong to the group of biocides, but are called plant protection products (PPP), phytosanitary products or pesticides, although technically they can be identical, i.e. have the same chemical structure. Products controlling unwanted organisms by mere physical or mechanical action are generally not considered as biocidal products.  Biocides Biocides are intended to be toxic, but only to the target organisms to be controlled. They are used in different areas like aquaculture, food industry, cleaning, personal protection, transportation, and preservation of wood and other biological products. Biocides thus encompass a wide range of applications including disinfection, preservation, and pest control. They protect health, improve product performance, prevent spoilage and are increasingly important to modern life in ensuring safe, long-lasting, and effective products.  Biocides Biocidal active substances are mostly chemical compounds but can also be micro-organisms like bacteria. Some of the most widely used biocides have disinfectant properties like alcohols, aldehydes, chlorine and chlorine-releasing agents (sodium hypochlorite), chlorhexidine, iodine, peroxygen compounds (hydrogen peroxide, peracetic acid). Furthermore, extracts and essential oils from plants (Chrysanthemum cinerariaefolium, ext.) and micro-organisms are used as insecticides. Biocidal products are mixtures, containing one or more active substances, and other non-active co-formulants that ensure or improve the effectiveness of the active substance, as well as the desired pH, viscosity, color, odor, etc., of the final product. Biocidal products are available on the market for use by professionals and/or non-professionals.  Biocides Biocide activity is affected by several factors, notably concentration, period of contact, pH, temperature, water hardness, the presence of organic matter or other interfering or enhancing materials or compounds, and the nature, numbers, location, and condition of the target organism (micro-organism like bacteria, spores, yeasts and molds, protozoa, insects, rats etc.). Understanding the mechanism of action of biocides is important in optimizing their use and combating resistance if encountered. Biocidal action may result through physicochemical interaction with microbial target structures, specific reactions with biological molecules, or disturbance of selected metabolic or energetic processes.  Chapter 7: Application of microbes in medical biotechnology 7.1 Antibiotics and drugs Biotechnology is widely used in different fields such as medicine, agriculture, food processing, etc. Biotechnology Applications in Medicine Biotechnology has a variety of applications in the field of medicine. Some of the biotechnology applications in medicine include the following:  1. Recombinant Insulin Insulin is required by diabetic patients to remove excess sugar from the blood. Diabetic patients have a very low level of insulin or no insulin produced by the body. Therefore, they need external insulin to control blood glucose levels. Later it was discovered that the insulin produced by the pancreas of the pigs can be used by humans. But there were not enough pigs to provide the quantities of insulin required. This led to the cloning of the human insulin gene. After the development of recombinant DNA technology in 1978, the specific gene sequence that codes for human insulin was identified, isolated and introduced to E.coli bacteria. The gene sequence altered the genetic composition of the E.coli cells. Within 24 hours, several genetically modified E.coli bacteria containing the recombinant human insulin gene started producing human insulin.  Gene Therapy Gene Therapy holds the most promising solution to the problem of genetic diseases. Gene therapy is used to treat genetic disorders usually by the insertion of a normal gene or correct gene for the defective or inactive gene into an individual with the help of vectors such as virus or vectors such as adenovirus, and herpes simplex virus. The normal gene replaces the defective or inactive gene and carries out its functions. The therapy has the highest chances of developing a permanent cure if introduced in the earliest stages of life.  Molecular Diagnosis Medical diagnosis is another application of biotechnology in the health sector. Many times the pathogen concentration increases by the time the disease is diagnosed. Hence, early diagnosis and knowledge of pathophysiology are essential for an effective cure. This can be achieved with the help of techniques such as Recombinant DNA Technology, Polymerase Chain Reaction (PCR) and Enzyme-Linked Immunosorbent Assay (ELISA), etc.  Pharmacogenomics Pharmacogenomics is the study of how our genes affect the way we respond to medications. The word “pharmacogenomics” comes from the words “pharmacology” (the study of the uses and effects of medications) and “genomics” (the study of genes and their functions). Pharmacogenomics is part of the field of precision medicine. It is used to prescribe a medication that leads to fewer side effects or that may work better for you. Examples include some medications for HIV, certain cancers, depression and heart disease. But this field of medicine is rapidly changing and advancing. Researchers are hopeful that pharmacogenomics will soon be able to help providers choose better medications to manage many common conditions.  Pharmacogenomics Pharmacogenomics has led to the production of drugs that are best suited to an individual’s genetic makeup. It can be applied in diseases such as cancer, depression, HIV, asthma, etc.  Vaccines Vaccines are obtained by animals and cell cultures. These vaccines contain inactivated pathogens. The transgenic plants can produce antigens that can be used as vaccines. Antigenic proteins from several pathogens can be expressed in plants such as tomato and banana. Transgenic sugar-beet can treat foot and mouth disease of animals, transgenic banana and tomato can cure diseases such as cholera and hepatitis B.  Other Biotechnology Applications 1. Fermentation is an ancient invention of biotechnology. Alcohol and bread are being produced since ages with the help of microorganisms such as yeast. In today’s scenario, the cultures have been purified and genetically refined to produce high- quality food products. 2. Crop improvement by crossing the plant breeds with desired traits is another application of biotechnology in the agriculture sector. E.g Agrobacterium 3. Transgenic plants are genetically engineered to produce plants with desired characteristics. 4. Tissue culture is another application of biotechnology to produce a large number of plants with an explant. It also helps in increasing the number of endangered plant species. 5. It is also helpful in forensics for the identification of criminals, or in paternal disputes.  Biotechnology Scope Biotechnology is applied to various fields and many industries such as food, pharmaceuticals, medicine, agriculture, etc.. Genetic engineering has helped in the production of therapeutic proteins as well as biological organisms. The scope of biotechnology is extended to various branches of Biology. Some of these include tissue culture, development of transgenic plants and animals, development of antibodies, etc. Antibioticproduced by microbes, is detrimental to other microorganisms. Antibiotics commonly are produced by soil microorganisms.  7.2 Hormones, vaccines, and other therapeutics What are Hormones? Hormones are chemicals that essentially function as messengers of the body. These chemicals are secreted by special glands known as the endocrine glands. These endocrine glands are distributed throughout the body. These messengers control many physiological functions as well as psychological health. They are also quite important in maintaining homeostasis in the body.  Hormones Peptide Hormones Peptide hormones are composed of amino acids and are soluble in water. Insulin is an important peptide hormone produced by the pancreas. Steroid Hormones Unlike peptide hormones, steroid hormones are fat-soluble and are able to pass through a cell membrane. Sex hormones such as testosterone, estrogen and progesterone are examples of steroid hormones.  List of Important Hormones Cortisol – It has been named as the “stress hormone” as it helps the body in responding to stress. This is done by increasing the heart rate, elevating blood sugar levels etc. Estrogen-This is the main sex hormone present in women which bring about puberty, prepares the uterus and body for pregnancy and even regulates the menstrual cycle. Estrogen level changes during menopause because of which women experience many uncomfortable symptoms. Melatonin – It primarily controls the circadian rhythm or sleep cycles. Progesterone – It is a female sex hormone also responsible for menstrual cycle, pregnancy and embryogenesis. Testosterone – This is the most important sex hormone synthesized in men, which cause puberty, muscle mass growth, and strengthen the bones and muscles, increase bone density and controls facial hair growth.  Vaccines. A vaccine is a biological preparation formulated to provide acquired immunity for a particular disease. When this preparation is introduced into the human body, the immune system is able to recognize the threat and destroy it. Moreover, the body will “remember” the threat and can initiate an appropriate response if encountered in the future. The process of administering the vaccine is called vaccination or immunization. It is responsible for the eradication of many diseases – especially infectious diseases such as smallpox and chickenpox, Covid -19. rDNA technology enables to produce recombinant vaccines through genetic modification of organisms.  Recombinant vaccines rDNA technology provides a new method for making vaccines to overcome the limitations of traditional vaccines. Recombinant DNA technology in recent years has become a boom to produce a new generation vaccines. Recently, recombinant DNA technology has helped to develop new generation vaccines, which are cheaper, safer and more effective. Biotechnology is helping us improve existing vaccines and create new vaccines against infectious agents, such as the viruses that cause cervical cancer and genital herpes. Various researchers are developing vaccines against diseases such as diabetes, chronic inflammatory disease, Alzheimer’sDisease and cancer.  Types of recombinant vaccines The recombinant vaccines may be broadly grouped into four A. Subunit recombinant vaccine B. Attenuated recombinant vaccines C. Vector recombinant vaccines D. DNA vaccines  recombinant vaccines Subunit vaccines are produced by genetic engineering. They are purified single proteins from the surface of a pathogen which can be produced cheaply in fermenters. The great advantage of subunit vaccines is that they contain no live, potentially infectious organisms. The synthetic vaccines are advantageous because the immune system of the animal is challenged with only one antigen, thereby omitting other components of the virion that might adversely affect the immune response. The major drawback with subunit/peptide vaccines is that the antigenic mass cannot be greater than the amount injected. There is no amplification of the antigen.  Procedure for sub unit vaccine production 1. Identifying protective proteins or epitopes on the proteins. 2. Identify the gene coding for the protein 3. Clone the gene coding for the specific protein and express it in suitable expression system 4. Purify the protective protein to homogeneity 5. The protein is used to immunize individuals against the disease ( hepatitis B).  Five strategies are currently being applied to the generation of new types of vaccines: 1. Recombinant DNA cloning of immunogenic surface protein 2. Chemical synthesis of polypeptide vaccines 3. Construction of recombinant vaccines having guest genes for foreign surface proteins. 4. Genetic engineering of non pathogenic mutant agents 5. Production of monoclonal epitopes of the surface proteins of infectious agents 6. Nucleic acid vaccines  Chapter 8: Application of microbes in environmental biotechnology Micro-organisms have several potential uses in the environment, for purposes as diverse as agriculture, pollution control, mining, and oil recovery. With the arrival of biotechnology, the potential of improving micro-organisms for selected uses has received increased attention and speculation.  Applications of Microbes in Environmental Biotechnology 1. Wastewater Treatment Microbial Treatment Systems: – Activated sludge: Aerobic bacteria degrade organic matter in sewage. – Anaerobic digestion: Methanogenic bacteria convert organic waste into biogas. Benefits: Reduces pollution, recycles water, and produces energy. 2. Bioremediation Definition: The process of using microorganisms to break down or detoxify pollutants in the environment. Applications of Microbes in Environmental Types: – In situ: Treatment occurs at the site of contamination. – Ex situ: Contaminated materials are removed for treatment elsewhere. Examples: – Oil spills: Bacteria like Pseudomonas can degrade hydrocarbons. – Heavy metals: Certain microbes can bioaccumulate or transform metals like arsenic, lead, and mercury.  Applications of Microbes in 3. Composting Environmental Process: Microbes decompose organic materials (food scraps, yard waste) into nutrient-rich compost. Benefits: – Reduces landfill waste. – Enhances soil fertility and structure. 4. Bioaugmentation Definition: The addition of specific microbial strains to contaminated environments to improve pollutant degradation. Examples: – Adding Dehalococcoides strains for the degradation of chlorinated solvents. 5. Phytoremediation Microbial Role: Microbes in the rhizosphere (root zone) of plants assist in breaking down contaminants. Example: Certain bacteria help plants absorb and detoxify heavy metals.  Applications of Microbes in Environmental 6. Biodegradation Definition: The breakdown of organic substances by microbial action. Importance: Reduces environmental pollution and recycles essential nutrients. 7. Bioleaching Process: Use of bacteria to extract metals from ores through bioleaching processes. Application: Recovery of metals like copper and gold from low-grade ores, reducing the need for harsh chemical methods. 8. Carbon Sequestration Microbial Involvement: Certain soil microbes can capture and store carbon dioxide, playing a role in mitigating climate change. Mechanisms: Microbial processes can enhance soil organic carbon storage.  Applications of Microbes in Environmental 9. Bioplastics Production Microbial Production: Some bacteria can synthesize biopolymers like polyhydroxyalkanoates (PHAs) from organic substrates. Benefits: Provides a sustainable alternative to petroleum-based plastics  8.1 Waste water treatment Wastewater treatment is a crucial process that aims to remove contaminants from sewage and industrial effluents before they are released into the environment or reused.  Stages of Wastewater Treatment Microbiology of waste water. Waste water is composed of clay, silt, debris, pathogens (bacteria, viral, protozoa, helminthes egg) organic and inorganic compounds. Waste are of two types, (domestic source and industrial source). Domestic sources are contaminated with faeces which are pathogens. Waste water should be discharged after treatment to remove pathogen and chemicals which are harmful. The purpose of waste water treatment is to minimize or reduce the potential danger of sewage to man and environment to reduce the level of pollution. This favors the self natural purification f water bodies. The basic function of waste treatment plant is to speed up the natural process by which water purifies itself. This is done by using microbes, aerobically in some stages, anaerobically in others. The anaerobic degradation of sewage solid (sludge) solubilized much of the materials and produce gas, methane which can be used as energy source for the plant.  Stages of Wastewater Treatment The aerobic process used to oxidize organic material and thereby decrease the demand of oxygen (BOD) of the final effluent. Low oxygen demand effluents required to maintain normal aquatic life in rivers and streams. Raw sewage approximately contain 106 bacterial/ml. The origin of bacteria in sewage are human and animal excreta, soil and air. The coliform groups is composed of two important species, such as E.coli and Aerobacteria aerogenes which can be useful in detecting sewage pollution  Water treatment process Wastewater treatment involves a series of processes to remove contaminants from water, ensuring that it is safe to discharge into the environment or reuse. Here are the primary steps: 1. Preliminary Treatment Screening: Removes large objects (like sticks, rags, and plastics) that could damage equipment. Grit Removal: Separates sand, gravel, and other heavy particles from the water. 2. Primary Treatment Sedimentation: Allows suspended solids to settle to the bottom, forming sludge, while lighter materials (like grease) float to the top. Primary Clarifiers: Tanks where sludge settles, and grease and oils are skimmed off.  Water treatment process 3. Secondary Treatment (Biological Treatment) Aeration: Oxygen is added to the wastewater, promoting the growth of bacteria and microorganisms that consume organic matter. Activated Sludge: A process where microorganisms break down organic pollutants. After aeration, the mixture goes to secondary clarifiers, where the "activated sludge" (microorganisms) settles out. Trickling Filters or Biofilters: Wastewater flows over a bed of stones or other media covered with bacteria that further degrade contaminants.  Water treatment process 4. Tertiary Treatment (Advanced Treatment) Filtration: Removes finer particles using sand, carbon, or membrane filters. Chemical Treatment: Uses chemicals like chlorine, ozone, or UV light to kill pathogens. Nutrient Removal: Removes nitrogen and phosphorus, which can cause environmental issues like eutrophication in receiving waters. 5. Disinfection Kills any remaining pathogens to protect human and environmental health. Common methods include chlorination, UV radiation, and ozonation.  Water treatment process 6. Sludge Treatment and Disposal Thickening: Increases the solids concentration of sludge. Digestion: Uses anaerobic bacteria to break down sludge, reducing volume and odors. Dewatering: Removes water from sludge, often using presses or centrifuges. Disposal/Use: Treated sludge can be disposed of in landfills, incinerated, or used as fertilizer if it meets safety standards. Waste water Screening Sedimentation Sludge (insoluble) Soluble liquid - Activated sldge Anaerobic Oxidation - Trickling filter - -- digestion - Aeration Digested sludges drying Disinfection incineration use as fertilizers or burial. Treated effluent released to stream/river/ Fig.4 Waste water treatment process summary  Water treatment Laboratory methods used to measure organic matter in sewage are 1. Biological oxygen demand (BOD) which is widely used. 2. Chemical oxygen demand (COD) oxidizing organic compounds. 3. Total organic matter (TOC) determined by oxidizing organic carbohydrates. 4. Theoretical oxygen demand. BOD measures organic pollution in sewage and surface water. BOD involves measurement of dissolved oxygen utilized by microorganisms. The more is the amount of organic matter, the higher is the BOD. If dissolved oxygen is less, organic matter decomposes anaerobically producing foul smell. Figure of Sewage treatment plant  Drinking water purification Drinking water purification involves several steps to ensure that water is clean, safe, and free from contaminants. Here’s an overview of the main stages in drinking water treatment: 1. Screening and Pre-treatment Screening: Removes large debris (like leaves, sticks, and trash) that could damage equipment. Coagulation and Flocculation: Chemicals (like aluminum sulfate) are added to water to form sticky particles called "flocs." These particles attract dirt, bacteria, and other impurities. 2. Sedimentation Settling Tanks: The flocs and suspended solids settle to the bottom of the tank due to gravity, forming sludge that can later be removed.  Drinking water purification 3. Filtration Sand and Gravel Filtration: Water passes through layers of sand, gravel, and sometimes anthracite coal, which trap smaller particles and impurities. Membrane Filtration: In some systems, finer membranes are used to remove smaller contaminants, including some viruses and bacteria. 4. Disinfection Chlorination: Adding chlorine kills remaining bacteria and viruses, providing a disinfecting residual to protect water as it travels through pipes. UV Radiation: Some facilities use ultraviolet light to disinfect water without adding chemicals. Ozonation: Ozone gas can also be used as a disinfectant and oxidizer to remove taste- and odor-causing compounds.  5. pH Adjustment pH Control: Adjusts the acidity of the water to protect pipes and improve taste. Lime or soda ash may be added to increase pH, or acids to decrease it, if necessary. 6. Fluoridation (Optional) Adding Fluoride: In some regions, fluoride is added to help prevent tooth decay. This is generally done after primary disinfection. 7. Final Filtration (Polishing) Carbon Filtration: Activated carbon filters are sometimes used to remove organic compounds, taste, and odors before the water enters the distribution system. 8. Storage and Distribution Storage Tanks: Treated water is stored in reservoirs or tanks, ready for distribution. Distribution: The purified water is distributed through a network of pipes  Drinking water purification 5. pH Adjustment pH Control: Adjusts the acidity of the water to protect pipes and improve taste. Lime or soda ash may be added to increase pH, or acids to decrease it, if necessary. 6. Fluoridation (Optional) Adding Fluoride: In some regions, fluoride is added to help prevent tooth decay. This is generally done after primary disinfection. 7. Final Filtration (Polishing) Carbon Filtration: Activated carbon filters are sometimes used to remove organic compounds, taste, and odors before the water enters the distribution system. 8. Storage and Distribution Storage Tanks: Treated water is stored in reservoirs or tanks, ready for distribution. Distribution: The purified water is distributed through a network of pipes to homes, businesses, and other facilities.  8.2 Solid waste treatment Solid waste treatment involves methods to manage and dispose of waste in an environmentally sound manner. Here are the main approaches: 1. Landfilling Controlled Disposal: Waste is buried in designated landfill sites, designed to minimize environmental impact. Leachate & Gas Management: Modern landfills have systems to capture leachate (liquid runoff) and methane gas produced during decomposition. 2. Incineration Thermal Treatment: Waste is burned at high temperatures, significantly reducing its volume. Energy Recovery: Incineration can generate energy, which is used to produce electricity or heat. Air Pollution Control: Filters and scrubbers remove harmful emissions before releasing gases into the atmosphere.  Solid waste treatment 3. Composting Biological Decomposition: Organic waste (like food scraps and yard waste) is broken down by bacteria, fungi, and other microorganisms. Fertilizer Production: Produces compost that enriches soil, useful for agriculture and landscaping. 4. Recycling Material Recovery: Sorting and reprocessing materials like plastic, metal, glass, and paper for reuse. Resource Conservation: Reduces the need for raw materials, saving energy and reducing pollution.  Solid waste treatment 5. Anaerobic Digestion Biodegradable Waste Treatment: Organic waste is decomposed in the absence of oxygen, producing biogas. Biogas Generation: The biogas can be used for electricity, heating, or as vehicle fuel. 6. Mechanical Biological Treatment (MBT) Combining Techniques: Involves mechanical sorting of recyclables, followed by biological treatment (like composting or anaerobic digestion) of organic waste. Residual Waste Reduction: Reduces the volume of waste sent to landfills by recovering valuable materials. These methods help reduce the environmental impact of waste, conserve resources, and, in some cases, recover energy.  8.3 Microbes in mineral recovery and bioenergy Microbes in Mineral Recovery 1. Bioleaching Definition: The use of microorganisms to extract metals from ores. Mechanism: Microbes oxidize metal sulfides, releasing soluble metal ions. Common Microbes: – Acidithiobacillus ferrooxidans: Oxidizes iron and sulfur, commonly used in copper and gold extraction. – Leptospirillum: Involved in the oxidation of ferrous iron. 2. Biomining Definition: The process of using microorganisms to mine for metals from ores or waste materials. Advantages: – Environmentally friendly compared to traditional mining methods. – Can extract metals from low-grade ores that are not economically viable with conventional techniques.  Microbes in Mineral Recovery 3. Recovery of Valuable Metals Metals: Gold, copper, uranium, nickel, and cobalt can be recovered using microbial processes. Process Steps: – Crushing and grinding: Preparation of ore. – Bioleaching: Application of microbial cultures to oxidize metals. – Recovery: Processing leachate to precipitate or extract metals.  Microbes in Bioenergy 1. Biogas Production Anaerobic Digestion: Microbial breakdown of organic materials in the absence of oxygen, producing biogas (mainly methane). Feedstocks: Agricultural waste, food waste, sewage sludge, and animal manure. Microbial Groups: – Methanogens: Archaea that convert carbon dioxide and hydrogen into methane. – Fermentative bacteria: Break down complex organic matter into simpler compounds.  Microbes in Bio-energy 2. Bioethanol Production Fermentation: Yeasts (e.g., Saccharomyces cerevisiae) convert sugars from biomass into ethanol. Feedstocks: Corn, sugarcane, and cellulosic materials (e.g., agricultural residues). Process: – Pretreatment: Break down lignocellulosic materials. – Fermentation: Conversion of sugars to ethanol. 3. Biodiesel Production Microbial Lipids: Certain microorganisms (e.g., microalgae) can produce oils that can be converted into biodiesel. Advantages: – Renewable and can be produced from waste materials. – Algal biodiesel has a higher yield per area compared to traditional crops.  Microbes in Bio-energy 4. Microbial Fuel Cells (MFCs) Definition: Devices that convert chemical energy from organic compounds directly into electricity using microbial metabolism. Mechanism: Microbes oxidize organic matter, transferring electrons to an anode and generating electricity. Applications: Wastewater treatment, remote power generation, and sensors. Microbial processes play a vital role in mineral recovery and bio- energy production, offering sustainable solutions for resource extraction and energy generation. By harnessing the capabilities of microbes, industries can reduce environmental impact and improve resource efficiency. These biotechnological applications are essential for developing a circular economy and addressing global energy and resource challenges