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Microbial Biotechnology (Bot3105) Part Two

• Course title: Microbial Biotechnology
• Course number: Bot3105
• Credit hours: 3
• Instructor: Million Yohannes, Senior Lecturer

Chapter 5: Application of Microbes in Food Biotechnology - Dairy Products

• Dairy products are derived from milk, the secretion of mammary glands of mammals (e.g., cows, sheep, goats).
• Most dairy products originate from bovine milk, and to a lesser extent, from sheep or goat milk.
• Milk contains approximately 80-90% water, making it susceptible to microbial growth and deterioration.
• Processing methods are used to prevent spoilage and extend shelf life.
• Examples of dairy products include ice cream, cheese, milk powders, yogurt, and butter/butteroil.
• Milk can be separated into cream and skim milk fractions using centrifugation.
• This process concentrates fat in the cream phase and reduces fat in the skim milk phase.

Chapter 5: Application of Microbes in Food Biotechnology - Further Info

• Milk powders are produced through water removal and high-temperature drying.
• Ice cream is a dairy product preserved via freezing.
• Yogurt and cheese are fermented products using bacterial cultures.
• Bacterial cultures lower pH (from 6.7 to 4.2 for yogurt; 4.6 to 6.0 for cheese), breaking down proteins and fats to enhance flavor.
• The bacterial cultures also compete with unwanted pathogens for nutrients, thus preserving the product.
• Milk preservation techniques use heat treatment for safety (pasteurization/batch pasteurization).
• Ultra-high temperature (UHT) treatment produces sterilized milk.
• High-pressure processing is another milk preservation method.

Heat Treatment of Milk

• Milk is often heat-treated for food safety and to extend shelf life.
• Pasteurization (162°F/72°C for 15 seconds) or batch pasteurization (145°F/63°C for 30 minutes) inactivates pathogens.
• Ultra-high temperature (UHT) treatment (284°F/140°C for 2-3 seconds under pressure) produces essentially sterile milk.
• High pressure processing can also be used for preservation.

Food Microbiology

• Food microbiology focuses on microorganisms in food, their reproduction, and spoilage.
• Safety in food processing is critical to avoid contamination by pathogenic microorganisms.
• Viruses (e.g., norovirus, hepatitis, rotavirus) and bacteria (e.g., Salmonella, E. coli, Vibrio, Shigella) can contaminate food, causing foodborne diseases.
• Spores of certain bacteria (e.g., Clostridium, Bacillus) can survive food preservation temperatures. Microbes multiply to a point where the food begins slime and off-flavor and odor and is considered spoiled.
• Yeasts and molds are other types of microorganisms that can affect food. Molds can produce toxins like aflatoxin which are carcinogenic.

Food Fermentation

• Fermentation is a microbial process where microorganisms convert food stuffs to alcohol or acids.
• Fermented foods generally retain longer shelf lives.
• Fermentation promotes the growth of beneficial bacteria (probiotics).
• Probiotics aid digestive and heart health, and fermented foods are nutritious, tasty, and energy-rich (e.g., milk, meat, fish, vegetables, fruits, seeds, beans).
• Fermented food groups include dairy (e.g. Yogurt, cheese, butter, kefir, and acidophilus milk), meats (e.g. Sausage, salami, and pickled meats), fruits/vegetables (e.g., Kimchi products), and beverages (e.g., beer and wine).

Food Fermentation - Industrial Applications

• Microorganisms can traditionally or by adding starters be used for industrial fermentation.
• Gram-positive bacteria are non-motile, non-sporing cocci-or rod-shaped, catalase and oxidase negative. They are useful in lactic-acid food fermentation.

Food Fermentation - Other Microorganisms

• Acetobacter is used to produce acid from alcohol.
• Yeasts and molds are key in fermentation for diverse reasons.

Dairy Microbiology

• Milk (if healthy) is an excellent medium for microbes.
• Milk is usually sterile until processing or contact with the outside world.
• Homofermentative bacteria produce only lactic acid, while heterofermentative bacteria also produce other compounds from carbohydrates.
• Other bacteria can lead to contamination.

Therapeutic LAB

• Biograde, Biofighurt, acidophilus milk – are examples of therapeutic bacteria in food products.
• Lactobacillus species and lactococus lactis sub species diacetylactis - give flavor to finished products (e.g., buttermilk, cultures milk, yogurt).

Food Preservation

• Food preservation methods aim to reduce spoilage and extend shelf life.
• These methods are categorized as chemical-based (e.g., addition of organic acids), physical-based (e.g., heating, freezing, smoking, drying), or microbiological-based (e.g., use of bacteriocins).

Chapter 6: Application of Microbes in Agro-Biotechnology

• Healthy agricultural production depends on soil quality, water, and fertilizers.
• Commercial fertilizers are useful for high yields but not environmentally friendly.
• A fertilizer is a chemical or natural substance helping crop production.
• Biofertilizers are biologically active and can improve soil fertility, like microbial inoculants for nitrogen fixation, using bacteria, fungi, or algae.

Bio-fertilizers and Feeds

• Biofertilizers are beneficial for plants compared to commercial fertilizers, as they increase crop yields, cost-effective, natural, readily available, or easy to produce without environmental contamination.
• Examples include Rhizobium, Azobacter, Thiobacillus, Bacillus, and mixtures of these, as well as use of manure/garbage.
• These biofertilizers use microorganisms to increase nitrogen/phosphorous levels, improving plant growth.

Animal Feed

• Animal feed often uses different feed formulations.
• This involves selecting and blending ingredients to create highly nutritious diets that promote animal health and improve product quality (e.g., meat, milk, and eggs).

Bio-controls and Biocides

• Biocontrol uses helpful microorganisms/insects/plants to stop harmful ones (e.g., predation, parasitism, pathogenicity, and competition against other microorganisms).
• This is a part of integrated pest management and involves adding no artificial substances/pesticides.
• Biocides are chemicals for killing/restraining harmful organisms/biological products. They can be for general purposes or part of agricultural practices.

Biocide overview

• Biocides are intended to be toxic, but only to the target organisms, which are frequently used in areas like aquaculture, food industries, cleaning, personal protection, transportation, and preservation of wood (or other biological products).
• These commonly include disinfection, control of pests, and preservation.
• Common biocides include: alcohols, aldehydes, chlorine, sodium hypochlorite, chlorhexidine, iodine, and peroxygen compounds.
• Active substances and co-formulants combine to form biocidal products. They enhance effectiveness (e.g., pH, viscosity, color, odor, etc.).

Chapter 7: Application of Microbes in Medical Biotechnology

• Biotechnology plays a major role in medicine (as in other fields like agriculture and food).
• Biotechnology applications in medicine include: recombinant insulin, gene therapy, molecular diagnosis, and pharmacogenomics.

Recombinant Insulin

• Recombinant DNA technology was employed to create human insulin from E. coli.
• This technique involves identifying, isolating, and introducing the human insulin gene into E. coli.
• Efficient, cost-effective, and safe human insulin production.

Gene Therapy

• Gene therapy aims to treat genetic disorders by inserting normal genes into those defective in individuals.
• This helps by using a vector (e.g., adenovirus, herpes simplex virus) which carries the normal gene to replace the dysfunctional one, aiming to restore proper function.
• Most successful if initiated in early life stages.

Molecular Diagnosis

• Early diagnosis can enable effective treatment of pathogens.
• Molecular diagnosis uses biotechnology techniques like recombinant DNA technology, PCR, and ELISA to identify pathogens early.

Pharmacogenomics

• Pharmacogenomics studies how genes affect a person's response to medications.
• Aiming to prevent adverse reactions, which could lead to more personalized medications and reduced side effects (e.g., HIV, cancers, depression, heart disease).

Vaccines

• Vaccines protect against various diseases (including those of animals).
• Vaccines can be produced through animal or cell cultures, inactivating pathogens, or using genetic technologies.
• Transgenic plant antigens are another source of vaccine production.
• Vaccines are a key part of a wider range of vaccinations for both humans and animals.

Other Biotechnology Applications

• Fermentation (e.g., alcohol and bread production), crop improvement, tissue culture (for plant production and cloning), and forensics have all benefited from biotechnological advances.

Biotechnology Scope

• Biotechnology is widespread in many industries such as food, pharmaceuticals, medicine, and agriculture.
• Genetic engineering helps produce therapeutic proteins and biological organisms.
• Various applications in biology (e.g., tissue culture, transgenic plants/animals, antibody development).
• Antibiotics, produced by soil microorganisms, have detrimental effects on other microorganisms.

Applications of Microbes in Environmental Biotechnology

• Microbes have important uses in many fields, including agriculture, wastewater treatment, bioremediation, composting, bioaugmentation, biodegradation, bioleaching, carbon sequestration, and bioplastics.
• Bioleaching extracts metals from ores, while biomining is their recovery from ores/waste.
• Biogas production, bioethanol production, biodiesel production, and microbial fuel cells (MFCs) are some other microbial applications in environmental and energy production.

Wastewater Treatment

• Wastewater treatment aims to remove contaminants from sewage and industrial effluents before release into the environment.
• Typical steps include screening, grit removal, sedimentation, biological treatment (e.g., aeration and activated sludge), filtration, disinfection, and sludge treatment and disposal.
• Water quality is greatly improved compared to without these methods.

Water Treatment Process

• Steps in purifying drinking water:

1. Screening/Pre-treatment: Removes large debris.
2. Coagulation/Flocculation: Forms flocs to attract impurities.
3. Sedimentation: Allows sludge to settle and be removed.
4. Filtration: Removes finer particles from water.
5. Disinfection: Kills pathogens (e.g., chlorination, UV radiation, ozonation).
6. pH adjustment: Adjusting pH for pipe protection and taste.
7. Fluoridation: Adding fluoride to prevent tooth decay.
8. Final Filtration/Polishing: Using carbon filters to remove tastes/odors.
9. Storage and distribution: Storing and transporting purified water.

Solid Waste Treatment

• Solid waste treatment manages and disposes of waste sustainably.

1. Landfilling: Waste burial in designated sites (managing leachate/gas).
2. Incineration: Burning waste to significantly reduce volume (recovering energy, managing air pollution).
3. Composting: Biological decomposition of organic waste into nutrient-rich compost.
4. Recycling: Sorting and reprocessing materials (conserving resources, reducing pollution).
5. Anaerobic Digestion: Biodegradable waste breakdown in the absence of oxygen producing biogas.
6. Mechanical Biological Treatment: Combining mechanical and biological treatment techniques (sorting, composting, anaerobic digestion).

Microbes in Mineral Recovery and Bioenergy

• Microbes are used to extract metals (e.g., gold, copper) from ores (bioleaching using Acidithiobacillus ferrooxidans/Leptospirillum).
• Extracting metals from low-grade ores using microorganisms, reducing environmental impact.
• Bioenergy involves using microbes for biogas production, bioethanol production, biodiesel production, and microbial fuel cells.

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