Topics to be Learn :

  • Improvement in Food Production
  • Plant breeding
  • Tissue culture
  • Single cell protein (SCP)
  • Biofortification
  • Animal husbandry
  • Microbes in human welfare
  • Role of Microbes in Industrial Production
  • Microbes in Sewage Treatment
  • Microbes in Energy Generation
  • Role of Microbes as Biocontrol Agents
  • Role of Microbes as Biofertilizers

Food:

Definition: Anything solid or liquid that is swallowed, digested, and assimilated in the body, sustaining our well-being.

Characteristics:

  • Organic: Derived from living organisms.
  • Energy-rich: Provides fuel for bodily functions.
  • Non-poisonous: Safe for consumption.
  • Edible: Suitable for eating.
  • Nourishing: Provides essential nutrients for growth and health.

Importance:

  • Basic need: Essential for survival.
  • Energy source: Provides energy for all living things.
  • Maintains health: Keeps us alive, strong, and healthy.
Role of Green Plants:
  • Synthesize food: Green plants produce their own food through photosynthesis.
  • Primary source: Animals, including humans, rely on plants directly for food.

Plant Breeding:

Definition: Improvement or purposeful manipulation of crop heredity to produce new superior varieties.

Objectives:

  • Increase crop yield
  • Improve quality of produce
  • Enhance tolerance to environmental stresses
  • Develop resistance to pathogens and insect pests
  • Alter lifespan

Methods: Introduction, Selection, Hybridization, Mutation breeding, Polyploidy breeding, Tissue culture, r-DNA technology, SCP (Single cell protein).

Hybridization:
  • Definition: Combining desirable traits of two or more varieties.
  • Technique: Creates new genetic combinations and exploits hybrid vigor.
Types of Hybridization:
  • Intravarietal: Within the same variety
  • Intervarietal: Between two varieties of the same species
  • Interspecific: Between two species of the same genus
  • Intergeneric: Between two genera of the same family
  • Wide/Distant Crosses: Between distantly related parental plants

Main Steps of Plant Breeding Program (Hybridization):

1. Collection of Variability:

  • Gathering diverse alleles for all genes in the crop.
  • Collecting and preserving wild species and relatives with desired traits.

Germplasm Conservation:

  • In Situ Conservation: Utilizing forests and natural reserves.
  • Ex Situ Conservation: Preserving through botanical gardens, seed banks, etc.

2. Evaluation and Selection of Parents:

  • Assessing collected germplasm for desirable and complementary traits.
  • Selfing selected parents for several generations to increase homozygosity.
  • Multiplying and using only pure lines in hybridization.

3. Hybridization:

  • Selecting one variety as the female (recurrent) parent and another lacking desired traits as the male parent (donor).
  • Artificially pollinating female parent with pollen from male parent's anthers.
  • Collecting hybrid seeds to grow the F1 generation.

4. Selection and Testing of Superior Recombinants:

  • Choosing F1 hybrid plants superior to both parents with high hybrid vigor.
  • Selfing these plants for several generations to ensure homozygosity and stability of desirable traits.

5. Testing, Release, and Commercialization of New Cultivars:

  • Evaluating selected lines for productivity, disease resistance, quality, etc.
  • Initial growth under controlled conditions and performance recording.
  • Growing lines in natural fields across different agro-climatic zones for at least three generations.
  • Releasing approved varieties for use by farmers.

Steps of Hybridization Technique:

  • Collection of variability from germplasm/gene bank
  • Evaluation and selection of parents
  • Selection of parent plants with different qualities
  • Selfing of selected parents for three to four generations for homozygosity
  • Identification of male (donor) and female (recurrent) parents
  • Collection of pollen grains from male parent flowers
  • Emasculation of female parent flowers
  • Artificial cross-pollination using collected pollen grains
  • Bagging and tagging of emasculated female parent flowers
  • Development of fruit and seeds representing F1 generation
  • Selection and testing of F1 hybrids for desirable traits
  • Field trials for yield assessment
  • Testing and release of new varieties

Green Revolution:

Definition: Introduction of high-yielding hybrid varieties of crops, leading to increased agricultural production.

Key Elements:

  • Use of improved crop varieties
  • Expansion of cultivable land
  • Optimum use of pesticides and fertilizers
  • Implementation of multiple cropping systems
  • Adoption of modern farm machinery
  • Establishment of proper irrigation systems

Contributor: Dr. Norman E. Borlaug awarded Nobel Prize for developing semi-dwarf wheat varieties.

Indian Hybrid Crops:

Wheat and Rice:

  • Hybrid Wheat Varieties: Sonalika, Kalyan Sona
  • Semi-Dwarf Rice Varieties: Jaya, Padma, Ratna

Sugar Cane:

  • Hybrid varieties developed from Saccharum barberi and S.officinarum.
  • Notable varieties: CO-419, CO-421, CO-453.

Millets:

  • Hybrid Maize (Ganga-3)
  • Jowar (CO-12)
  • Bajra (Niphad)
Plant Breeding for Disease Resistance:
  • Objective: Develop inherent plant qualities to resist pathogens and diseases.
  • Methods: Carried out through hybridization.

Some Pathogens and Plant Diseases:

  • Fungi: Brown rust of wheat, Red rot of sugarcane, Late blight of potato.
  • Bacteria: Black rot of crucifers
  • Viruses:Tobacco mosaic virus

Developed Disease-Resistant Plants:

  • Wheat: Variety: Himgiri, Target Insect Pest: Leaf and stripe rust, hill bunt
  • Brassica: Varieties: Pusa Swarnim, Target Insect Pests: White rust
  • Cauliflower: Varieties: Pusa Shubra, Target Insect Pests: Black rot and Curl blight black rot
  • Chilli: Varieties: Pusa SadabaharTarget Insect Pests: Chilli mosaic virus, Tobacco mosaic virus, leaf curl
Mutation Breeding:

Mutation: Sudden heritable change in genotype, occurring naturally or induced artificially.

Induction Methods:

  • Natural Mutagens: High temperature, CO2 concentration, X-rays, UV rays.
  • Chemical Mutagens: Nitrous acid, EMS, Mustard gas, Colchicine, etc.

Effects of Mutagens:

  • Cause gene mutations and chromosomal aberrations.
  • Seedlings or seeds irradiated or exposed to mutagens for inducing mutations.

Mutant Varieties:

  • Rice: Jagannath
  • Wheat: NP 836 (rust resistant)
  • Cotton: Indore-2 (resistant to bollworm)
  • Cabbage: Regina-II (resistant to bacterial rot)
Plant Breeding for Insect Pest Resistance:

Methods of Developing Resistance:

Morphological Characters:

  • Hairy Leaves in Cotton: Provides resistance against jassids.
  • Hairy Leaves in Wheat: Offers resistance against cereal leaf beetle.
  • Solid Stem in Wheat: Confers resistance to stem borers.

Biochemical Characters:

  • High aspartic acid and low nitrogen/sugar content in maize: Provides resistance against stem borers.
  • Nectar-less cotton with smooth leaves: Confers resistance against bollworms.

Pest Resistant Varieties:

  • Brassica: Variety: Pusa Gaurav, Target Insect Pest: Aphids
  • Flat Bean: Varieties: Pusa Sem 2, Pusa Sem 3, Target Insect Pests: Jassids, aphids, fruit borer
  • Okra: Varieties: Pusa Sawani, Pusa A-4, Target Insect Pests: Shoot and fruit borer
Tissue Culture
  • Definition: Growing isolated cells, tissues, or organs in vitro on a solid or liquid nutrient medium, under controlled conditions.
  • Explant: The part of the plant used in tissue culture.
  • Totipotency: Ability of living plant cells to grow, divide, and regenerate into a whole plant.
  • Pioneers: Haberlandt (1902) proposed in vitro cell culture for plant morphogenesis. 
  • Medium Components:Consists of essential minerals, carbohydrates, proteins, fats, water, growth hormones, vitamins, and agar (for callus culture). Preferred medium: MS (Murashige and Skoog) medium.
Types of Tissue Culture:
  • Based on Explant Nature: Cell culture, organ culture, embryo culture.
  • Based on Growth Type: Callus culture (solid medium), Suspension culture (liquid medium).

Requirements:

Aseptic Conditions Maintenance:

  • Sterilization of glassware using detergents, hot air oven.
  • Sterilization of nutrient medium via autoclave.
  • Sterilization of explant using 20% ethyl alcohol and 0.1% HgCl2.
  • Sterilization of inoculation chamber (Laminar air flow) using UV rays.
Temperature: 18°C to 20°C
pH of Nutrient Medium: 5 to 5.8
Aeration: Especially important for suspension culture.

Steps for Tissue Culture Technique
  1. Cleaning and Sterilization: Clean glassware and instruments, Sterilize in an oven or autoclave.
  2. Preparation of Nutrient Medium: Select and prepare MS medium with known concentrations and proportions, Sterilize the medium in an autoclave.
  3. Preparation of Plant Material (Explant): Isolate explant from the growing stock plant, Surface sterilize and rinse the explant with water.
  4. Inoculation: Place the sterilized explant in a culture flask containing sterilized nutrient medium, Perform inoculation in a laminar airflow cabinet.
  5. Incubation: Incubate the inoculated explant, Cells grow and proliferate to form callus within 2-3 weeks.
  6. Sub-culturing: If callus is to be maintained longer, divide it into segments and transfer to fresh medium.
  7. Organogenesis: Initiate rooting and shooting from the callus, leading to plantlet formation.
  8. Hardening: Transfer plantlets to polythene bags with sterilized soil, Maintain low light and high humidity conditions.
  9. Transfer to Field: Transplant hardened plantlets to the field.

Sub Culturing

Callus Culture:

  • Nutrient medium solidified with agar-agar.
  • No need for shaker or agitator.
  • Sterilized explant placed on solid medium.
  • Cells absorb nutrients and multiply, forming callus.
  • Callus: mass of undifferentiated cells.
  • Growth hormones induce organ formation.
  • Auxins promote root formation, cytokinins promote shoot formation.
  • Requires subculturing for continuous growth.

Suspension Culture:

  • Cells transferred to liquid medium.
  • Medium agitated with shakers.
  • Agitation ensures aeration, mixing, and prevents cell aggregation.
  • Consists mainly of single isolated cells and small clumps.
  • Grows faster than callus culture.
  • Used for cell biomass production, biochemical isolation, and plant regeneration.

Applications of Tissue Culture:

  • Produces healthy plants from diseased ones using apical meristems.
  • Develops stress-resistant plants.
  • Produces haploid plantlets through pollen culture.
  • Generates secondary metabolites like alkaloids, enzymes, and hormones.
  • Multiplicates rare and endangered plants.
  • Produces somaclonal variants.
  • Used for large-scale production of genetically identical plants.
  • Includes protoplast culture.
  • Applications in forestry, agriculture, horticulture, genetic engineering, and physiology.

Micropropagation (Clonal Propagation):

  • Also known as tissue culture technique.
  • Regenerates large number of plants through organogenesis.
  • Adopted by Indian plant biotechnologists in various industries.

Applications of Micropropagation:

  • Rapid multiplication of genetically similar plants.
  • Produces many plantlets quickly and in a small space.
  • Independent of seasons, plants available year-round.
  • Maintains desirable traits of superior varieties for many generations.
  • Multiplies rare and endangered species, conserves biodiversity.
  • Generates new varieties through somatic hybrids.
  • Commercial production of ornamental and fruit plants.

Single Cell Protein (SCP):
  • Addresses protein malnutrition in underdeveloped and developing countries.
  • Produced through unconventional method of microbial cultivation.

Production Process:

  • Microorganisms like algae, fungi, yeast, and bacteria cultivated on waste or inexpensive substrates.
  • Substrates include wood shavings, corn cobs, sugar cane molasses, etc.
  • SCP rich in proteins, vitamins, minerals, and fats.

Microorganisms Used:

  • Fungi: Aspergillus niger, Trichoderma viride.
  • Yeast: Saccharomyces cerevisiae, Candida utilis.
  • Algae: Spirulina spp, Chlorella pyrenoidosa.
  • Bacteria: Methylophilus methylotrophus, Bacillus megasterium.

Advantages:

  • Rapid multiplication rate of microorganisms enables quick biomass production.
  • Microbes can be genetically modified to vary amino acid composition.
  • Utilizes diverse raw materials, reducing pollutants.
  • Rich source of vitamins, amino acids, minerals, and crude fibers.
  • Used in animal fodder, fish breeding, and cattle farming.
Biofortification: Method to enhance crops' vitamin, mineral, and fat content to combat malnutrition.

Objectives: Improve protein, oil, vitamin, and micronutrient content and quality.

Development Methods:

  • Conventional selective breeding and r-DNA technology employed.
  • Aims to enhance nutritional value during plant growth.

Examples:

  • Fortified Maize: Double lysine and tryptophan amino acids.
  • Wheat - Atlas 66: High protein content.
  • Iron-Fortified Rice: Five times more iron.
  • Vegetables: Carrot and spinach rich in vitamin A and minerals.
  • Vitamin C Enriched: Bitter gourd and tomato by IARI.
Animal Husbandry:
  • Agricultural practice of breeding and raising livestock.
  • Includes care and breeding of various animals like buffaloes, cows, pigs, horses, etc.
  • Encompasses poultry farming, fish farming, beekeeping, sericulture, and lac culture.
  • Products obtained: Milk, eggs, meat, wool, honey, silk.

Increasing Production:

  • Effective management procedures.
  • Implementation of new technologies to enhance quality and productivity.
  • Utilization of industrial principles in production, processing, and marketing.

Farm Management:

  • Selection of high-yielding breeds.
  • Provision of adequate nutrition and cleanliness.
  • Veterinary supervision, vaccination, and health maintenance.
Animal Breeding:

Aims:

  • Obtain improved breeds with desirable qualities.
  • Develop breeds with increased milk production, meat quality, or egg yield.

Types of Breeding:

Breed:Group of animals related by descent and similar in most characters like appearance, size, etc.

Breeding Types:

1. Inbreeding: Mating closely related individuals within the same breed for 4 to 6 generations.

  • Merits: Increases homozygosity,Helps in obtaining pure lines and eliminating harmful genes.
  • Demerits: Reduces fertility and productivity (inbreeding depression).

2. Outbreeding:

  • Involves breeding of two unrelated animals.
  • Three types: outcrossing, cross-breeding, interspecific hybridization.

(i) Outcrossing:

  • Mating animals of the same breed with no common ancestors for 4 to 6 generations.
  • Used to overcome inbreeding depression.

(ii) Crossbreeding:

  • Superior males of one breed mate with superior females of another breed.
  • Develops new breeds with desirable traits.
  • Example: Hisardale (Bikaneri ewes and Marino rams) sheep breed.

(iii) Interspecific Hybridization:

  • Breeding animals of two different but related species.
  • Produces animals with desirable traits from both parents.
  • Example: Mule (horse and donkey).
  • May not always be successful.

Artificial Insemination (AI):

Definition: Technique for controlled breeding experiments.

Process:

  • Select superior males of a commercial breed.
  • Collect semen and inject it into the female's genital tract.
  • Semen can be used immediately or frozen for later use.

Advantages: Easy and overcomes problems of normal mating.

Multiple Ovulation Embryo Transfer (MOET):

  • Increases chances of producing hybrids successfully.
  • Cow administered with Follicle Stimulating Hormone (FSH) for follicular maturation and super ovulation.
  • 6 to 8 eggs mature simultaneously.
  • Cow mated with superior bull or artificially inseminated.
  • Blastocysts recovered and transferred to surrogate mothers.
  • Genetic mother subjected to another round of super ovulation.

Applications:

  • Producing high milk yielding breeds and quality meat yielding bulls.
  • Increasing herd size quickly.

Dairy Farm Management:

Dairy Industry:

  • Involves production, processing, marketing, and distribution of milk and milk products.
  • Additional income sources: cow dung, manure, fuel cakes, and gobar gas.

Breeds of Cows:

  • Indian Breeds: Sahiwal, Sindhi, Gir.
  • Exotic Breeds: Jersey, Brown Swiss, Holstein.

Breeds of Buffaloes in India: Jaffarabadi, Mehsana, Murrah, Nagpuri, Nili, Surati.

Cattle Feed: Silage, oilcakes, minerals, vitamins, and salts.

Measures to Improve Milk Quality:

  • Select high-yielding breeds suitable for local climate and disease resistance.
  • Provide proper care and feed, including silage supplemented with oilcakes, minerals, vitamins, and salts.
  • Maintain cleanliness and hygiene during milking, storage, and transport.
  • Adopt mechanized processes to reduce direct contact with produce.
  • Maintain clean and spacious sheds with adequate facilities.
  • Seek veterinary assistance for health problems and diseases.
  • Ensure efficient transportation, processing, marketing, and distribution.

Poultry Farm Management:

Poultry Species: Includes chicken, ducks, turkey, and fowls for eggs and meat.

Allied Professions: Processing of eggs and meat, marketing of poultry products, compounding and sale of poultry feed, poultry equipment, pharmaceuticals, feed additives, etc.

Requirements for Poultry Farm Management:

  • Select proper, disease-free breeds and ensure safe farm conditions.
  • Maintain proper feeding practices with high-quality feed and water.
  • Ensure hygiene and health care for the birds.
  • Management of layers includes selecting high-yielding chicken, maintaining clean and well-ventilated farms, proper feed schedules, and other aspects like debeaking.
  • Infrastructure importance includes adequate lighting, proper waterer placement, sanitation, culling, and vaccination.
  • Management of broilers involves breed selection, housing, temperature regulation, ventilation, floor space observation, and broiler feed.

Poultry Breeds (Based on Origin):

  • American Breeds: Plymouth Rock, New Hampshire, Rhode Island Red.
  • Asiatic Breeds: Brahma, Cochin, Langshan.
  • Mediterranean Breeds: Leghorn, Minorca.
  • English Breed: Australorp.
  • Indian Breeds: Chittagong, Aseel, Brahma, Kadaknath.

Best Layer (Eggs): Leghorn.

Best Broilers (Meat): Plymouth Rock, Rhode Island Red, Aseel, Brahma, Kadaknath.

Poultry Diseases:

  • Viral Diseases: Ranikhet, Bronchitis, Avian influenza (bird flu).
  • Bacterial Diseases: Pullorum, Cholera, Typhoid, TB, CRD (chronic respiratory disease), Enteritis.
  • Fungal Diseases: Aspergillosis, Favus, Thrush.
  • Parasitic Diseases: Lice infection, roundworm, caecal worm infections.
  • Protozoan Diseases: Coccidiosis.
Apiculture or Beekeeping:

Definition: Apiculture or beekeeping involves the artificial rearing of honey bees to obtain bee products.

Importance:

  • Beekeeping yields various products like honey, wax, pollen, bee venom, propolis (bee glue), and royal jelly.
  • Honey is used in Ayurvedic medicine and as a nutritional food.
  • Bees aid in cross-pollination, enhancing productivity in pastures, wild shrubs, fruit orchards, and cultivated crops.
  • It provides employment opportunities in rural areas, complementing agriculture.

Species of Honey Bee:

  • Common species in India: Apis dorsata (rock bee or wild bee), Apis florea (little bee), Apis mellifera (European bee), and Apis indica (Indian bee).
  • Apis mellifera and Apis indica are suitable for beekeeping.

Requirements:

  • Suitable areas with abundant wild shrubs, fruit orchards, and cultivated crops.
  • Equipment includes bee hive boxes with comb foundation sheets, bee veil, smoker, bee brush, gloves, gumshoes, uncapping knives, swarm net, queen excluder, hive tool, etc.
  • Knowledge of bee habits, selecting suitable locations, catching and hiving swarms, managing hives, handling honey and other products, and periodic inspection for hive cleanliness and bee activity.
Fishery Overview:

Fishery involves activities related to catching, processing, fish farming, and marketing of fish and other aquatic animals like prawns, lobsters, oysters, mussels, and crabs.

Main Divisions:

Capture Fishery:

  • Inland Fishery: Involves culturing and capturing fish from freshwater bodies like rivers, ponds, lakes, and dams.
  • Marine Fishery: Involves capturing fish from seawater. India has a coastline of about 7500 km.
  • Estuarine Fishery: Involves capturing fish from estuaries.

Culture Fishery:

  • Polyculture: Different species are cultured simultaneously in the same pond.
  • Monoculture: Only a single species is cultured.

Common Fish Species:

  • Freshwater Fishes: Rohu, Catla, Mrigal, common carp, grass carp, silver carp, etc.
  • Marine Fishes: Hilsa, Bombayduck, sardines, pomphrets, mackerel, etc.

Fish Farming: Fish farming is the practice of culturing edible and commercially important fish species in ponds, lakes, or reservoirs.

Aspects of Fish Farm Maintenance:

  • Site Selection: Choosing an appropriate location for the fish farm.
  • Pond Excavation: Digging and preparing ponds for fish cultivation.
  • Hatchery Management: Maintaining facilities for hatching fish eggs.
  • Nursery Management: Rearing fish fry until they are ready for stocking in grow-out ponds.
  • Rearing Ponds: Managing ponds where fish are grown to marketable size.
  • Stocking Ponds: Introducing fish into grow-out ponds.
  • Water Source Management: Ensuring proper water quality and availability.
  • Supplying Fertilizer and Feed: Providing necessary nutrients and supplementary feed for fish growth.

Prevention of Fish Spoilage:

Fish is highly perishable and begins to spoil immediately after catching. To prevent spoilage, various preservation methods are employed:

  1. Chilling: Covering the fish with layers of ice to maintain low temperatures.
  2. Freezing: Long-term preservation by freezing fish at 0°C to −20°C.
  3. Freeze Drying: Deep-frozen fish at −20°C are dried by direct sublimation of ice to water vapor.
  4. Sun Drying: Inhibits microbial growth by exposing fish to sunlight.
  5. Smoke Drying: Fish is smoked using woods with low resin content. The acidic smoke destroys bacteria and imparts flavor.
  6. Salting: Removal of moisture from fish tissues by osmosis. High salt concentration inhibits bacterial activity.
  7. Canning: Sealing fish in containers, sterilizing with heat, and cooling for storage.

Economic Importance of Fisheries:

  • Nutritious Food: Fish is a source of essential vitamins, minerals, and nutrients.
  • By-products: Fish oil, fish meal, fertilizers, fish glue, and Isinglass are obtained from fish and used in various industries.
  • Export Value: Organisms like prawns and lobsters have high export value and market demand.
  • Employment: Fish farming and related fisheries activities provide job opportunities and self-employment.
  • Economic Boost: Fish farming contributes to the productivity and economy of nations.

Sericulture: Sericulture involves the rearing of silkworms and the production of silk.
  • Silkworm Rearing: Silkworms, particularly the Bombyx mori species, are reared to obtain high-quality silk, known as mulberry silk. Other varieties such as Tussar silk and Eri silk are also produced.
  • Feeding: Silkworm larvae are fed mulberry leaves, and the quality and quantity of silk depend on the quality of these leaves.
  • Care and Management: Skilled labor carefully rear and care for the silkworm larvae, protecting them from predators and diseases.
  • Cocoon Formation: Silk is obtained from the cocoon of the silkworm. The larvae spin silk fibers to form cocoons, secreting fibroin protein and sericin gum.

Life Cycle of Silkworm:

  1. Egg Stage: Silkworm eggs hatch into larvae.
  2. Larval Stage: Larvae develop into caterpillars and feed on mulberry leaves.
  3. Pupal Stage: After growth and moulting, the silkworm forms a cocoon.
  4. Adult Stage: The cocooned silkworm develops into an adult moth, completing the life cycle.

Cocoon Formation Process:

  • The silkworm secretes silk fibers from its salivary glands to form the cocoon.
  • Silk solidifies upon exposure to air, creating a continuous filament.
  • A single silkworm spins approximately one mile of filament to enclose itself completely in a cocoon in two to three days.

Sericulture is an ancient practice that requires scientific knowledge and skill. It can be started with low investment and space, making it accessible even to disabled or older individuals. 

Lac Culture:

Lac culture involves the harvesting of lac, a pink-colored resin secreted by the dermal glands of the female lac insect (Trachardia lacca). This resin hardens upon exposure to air, forming lac.

  • Composition of Lac: Lac is a complex substance containing resin, sugar, water, minerals, and alkaline substances.
  • Habitat and Feeding: The lac insect is colonial and feeds on succulent twigs of various plants like ber, peepal, palas, kusum, and babool.
  • Artificial Inoculation: Plants are artificially inoculated to ensure a regular and better supply of high-quality lac.
  • Processing: Natural lac is often contaminated, and the pure form is obtained by washing and filtering, known as shellac.

Uses of Lac:

  • Crafts: Lac is used for making bangles, various types of toys, and in woodwork.
  • Polish: It is a key ingredient in making polish.
  • Inks: Inks can be prepared from lac.
  • Mirror Silvering: Lac is used in the process of silvering mirrors.

Origins and Production:

  • The lac insect is native to India, and the country accounts for 85% of the world's lac production.
  • Lac culture plays a significant role in various industries and crafts, making it an economically important practice in many regions.

Microbes in Human Welfare

Biotechnology: Defined as applications of Scientific and Engineering principles for processing materials by biological agents for human welfare.

Application of Microbes:

  • Various microorganisms like algae, fungi, bacteria, viruses, protozoans, nematodes, etc., and their products are used for human welfare in food, health, industry, agriculture, medicine, and biocontrol.
  • Utilized in food and feed technology, industry, waste utilization, and energy.

Microbes in Food Preparation:

  • Lactobacilli used in dhokla fermentation from gram flour and buttermilk.
  • Dosa and idlis prepared with rice and black gram batter fermented by air-borne Leuconostoc and Streptococcus bacteria.
  • Some mushrooms and truffles are consumed directly, being sugar-free, fat-free, rich in proteins, vitamins, minerals, and amino acids.
  • Curd made by inoculating milk with Lactobacillus acidophilus, causing coagulation and partial digestion of milk protein casein.
  • Buttermilk is the acidulated liquid after churning butter from curd. 
  • Cheese production involves coagulating milk with LAB, filtering the curd, and ripening with mold for flavor.
  • Roquefort cheese ripened by Penicillium roquefortii.
  • Camembert cheese ripened by Penicillium camembertii.
  • Swiss cheese ripened by Propionibacterium shermanii, causing large holes due to CO2 production.
Role of Microbes in Industrial Production
  • Fermentation and Fermenters:Fermentation on an industrial scale involves growing microbes in large vessels called fermenters.
  • Fermenters provide a controlled environment for the growth of microorganisms to obtain desired products.

Products of Fermentation:

  • During fermentation, a variety of products such as alcoholic beverages, organic acids, vitamins, growth hormones, enzymes, antibiotics, etc., are produced.
  • These are secondary metabolites, not required for microbial growth, and are produced depending on the microorganism and substrate.

Production of Alcoholic Beverages:

  • Alcoholic beverages result from the alcoholic fermentation of specific substrates.
  • Tubular tower fermenters are used for large-scale production.
  • Beer is produced from barley, wine from grapes, and whisky from mixed grains like wheat, barley, and corn.
  • Saccharomyces cerevisiae strains are used for beer production.
  • Distilled alcoholic beverages include whisky, rum, and brandy, while beer and wine are produced without distillation.
  • Traditional drinks like Toddy are made by fermenting sugar sap from palms, and Fenny is fermented from cashew fruit pedicels.
Production of Organic Acids: Microbes are utilized in producing various organic acids.
  • Examples include:
  • Aspergillus niger produces citric acid.
  • Aspergillus niger also produces gluconic acid.
  • Rhizopus arrhizus is involved in the production of fumaric acid.
  • Acetobacter aceti produces acetic acid, commonly known as vinegar.

Production of Vitamins:

  • Vitamins are organic nitrogenous compounds crucial for vital functions in the body.
  • Microbes play a role in the industrial production of vitamins like thiamine (B1), riboflavin (B2), pyridoxine, folic acid, pantothenic acid, biotin, B12, ascorbic acid (C), beta-carotene (provitamin A), and ergosterol (provitamin D).
  • Examples include:
  • Neurospora gossypii and Eremothecium ashbyi produce vitamin B2.
  • Pseudomonas denitrificans is involved in the production of vitamin B12.
  • Aspergillus niger produces vitamin C.

Production of Antibiotics:

  • Antibiotics are secondary metabolites produced by certain microbes to inhibit the growth of other microbial pathogens.
  • They are used to treat diseases like plague, whooping cough, diphtheria, and leprosy.
  • Examples of common antibiotics and their microbial sources include:
  • Chloromycetin: Produced by Streptomyces venezuelae.
  • Erythromycin: Produced by Streptomyces erythreus.
  • Penicillin: Produced by Penicillium chrysogenum.
  • Streptomycin: Produced by Streptomyces griseus.
  • Griseofulvin: Produced by Penicillium griseofulvum.
  • Bacitracin: Produced by Bacillus licheniformis.
  • Oxytetracycline / Terramycin: Produced by Streptomyces aurifaciens.

Production of Enzymes:
  • Enzymes are biocatalyst proteins essential for accelerating biochemical processes.
  • Many microbes synthesize and excrete enzymes into the surrounding medium, enabling commercial production of enzymes such as Amylase, Cellulase, Protease, Lipase, Pectinase, Streptokinase, etc.

Uses of Enzymes in Various Industries:

  • Textile industry: Improve fabric quality.
  • Pulp and paper industry: Biomechanical pulping and bleaching.
  • Food industry: Fermentation for bread, wine, and beer production.
  • Detergent industry: Lipase for superior cleaning and oil stain removal.
  • Extraction industries: Carotenoids and olive oil extraction.
  • Cosmetics, animal feed, agricultural industries, etc.
  • Streptokinase has a fibrinolytic effect, used as a 'clot buster' in heart patients.

Enzyme and Microbial Source:

  • Invertase: Saccharomyces cerevisiae
  • Pectinase: Sclerotinia libertine, Aspergillus niger
  • Lipase: Candida lipolytica
  • Cellulase: Trichoderma konigii

Gibberellin Production: Gibberellins are growth hormones promoting stem elongation, mainly produced by higher plants and fungi.

Applications of Gibberellins:

  • Induce parthenocarpy in fruits like pear and apple.
  • Promote growth via stem elongation.
  • Break seed dormancy.
  • Induce flowering in long-day plants under short-day conditions.
  • Enlarge grape size.
Microbes in Sewage Treatment: Sewage is waste matter carried off in drainage.
  • Composition of Sewage:
  • Varies based on industrial source: textile, chemicals, pharmaceuticals, dairy, canning, brewing, meat packing, tannery, oil refineries, and meat industries.
  • Contains human excreta, animal dung, household waste, slaughterhouse waste, dissolved organic matter, algae, nematodes, pathogenic bacteria, viruses, protozoa, hospital, industrial, tannery, and pharmaceutical waste.
  • Consists mostly of water (99.5% to 99.9%) and inorganic/organic matter (0.1 to 0.5%).

Microorganisms in Sewage:

  • Includes bacteria from soil and pathogenic microorganisms causing dysentery, cholera, typhoid, polio, infectious hepatitis, and soil bacteria.
  • Bacteria: coliforms, fecal Streptococci, anaerobic spore-forming Bacilli, and others from human intestinal tract.
 

Sewage Treatment:

  • Preliminary Treatment: Screening and Grit Chamber.
  • Primary Treatment (Physical): Involves primary sedimentation tanks.
  • Secondary Treatment (Biological): Treatment in aeration tanks.
  • Tertiary Treatment: Passage through settling tank and anaerobic sludge digesters.
  • Effluents chlorinated before release into natural water bodies; digested sludge disposed

Microbes in Energy Generation:Biogas:
  • Used as fuel for domestic and industrial purposes.
  • Non-conventional, renewable energy source obtained by microbial fermentation.
  • Mixture of methane (CH4, 50-60%), CO2 (30-40%), H2S (0-3%), and trace gases (CO, N2, H2).
  • Highly inflammable and utilized as an energy source.

Substrates for Biogas Production: Cattle dung (common), plant, animal, domestic, agricultural, municipal, and forestry wastes.

Biogas Production:


  • Models by KVIC and IARI.
  • Consists of digester and gas holder.
  • Raw materials like cow dung mixed with water to form slurry, fed into the digester.

Anaerobic Digestion Processes:

  • Hydrolysis or Solubilization: Anaerobic hydrolyzing bacteria (Clostridium, Pseudomonas) break down carbohydrates, proteins, and lipids into simpler forms.
  • Acidogenesis: Acidogenic bacteria convert simple organics into acids (formic, acetic), H2, and CO2.
  • Methanogenesis: Methanogenic bacteria convert acetate, H2, CO2 into methane, CO2, H2O, and other products.

Benefits of Biogas:

  • Cheap, safe, and renewable.
  • Easily generated, stored, and transported.
  • Used for lighting, cooking, street lighting, and small-scale industries.
  • Burns with blue flame, smokeless.
  • Improves surrounding sanitation.
  • Eco-friendly, no pollution.
  • Sludge used as fertilizer.

 Role of Microbes as Biocontrol Agents:

  • Biocontrol:
    • Natural method of eliminating insects, pests, and disease-causing agents using biological enemies.
    • Microbes (bacteria, fungi, viruses, protozoans) act as biocontrol agents, causing disease, competing with, or killing pests.

Examples of Microbial Bio-control:

  • Bacillus thuringiensis (Bt): Eliminates butterflies, caterpillars.
  • Trichoderma species: Effective against soil-borne fungal plant pathogens.

Groups of Biocontrol Agents: Bacteria, fungi, viruses, protozoans.

Microbial Pesticides and Hosts: 

Bioherbicides:

  • Kill weeds competing with the main crop for resources.
  • Act as collateral hosts for pathogens.

Pathogenic Fungi as Mycoherbicides:

  • Phytophthora palmivora: Controls milkweed in orchards.
  • Alternaria crassa: Controls water hyacinth.
  • Fusarium spp.: Controls most weeds.

Bacterial Pathogen as Herbicides: Pseudomonas spp., Xanthomonas spp., Agrobacterium spp.: Attack various weeds.

Insects as Herbicides:

  • Tyrea moth: Controls Senecio jacobeac weed.
  • Cactoblastis cactorum: Controls cacti weeds.

Role of Microbes as Biofertilizers:Fertilizers:
  • Essential nutrients for plant growth and productivity.
  • Applied to plants, soil, or composting pits to increase soil fertility.
  • Biofertilizers: Cost-effective and eco-friendly alternatives.
Classification of Biofertilizers:
Nature or Group of Organisms:
  • Bacterial fertilizers
  • Fungal fertilizers
Function:
  • Bacterial fertilizers: Nitrogen-fixing, Phosphate-solubilizing
  • Compost-making
  • Cyanobacterial biofertilizers: Nitrogen-fixing
  • Fungal biofertilizers: Ectomycorrhizae, Endomycorrhizae

Bacterial Biofertilizers:Nitrogen-Fixing:
  • Convert atmospheric nitrogen into nitrogen compounds (ammonia, nitrites, nitrates).
  • Examples: Rhizobium (symbiotic with legumes), Azotobacter, Azospirillum.
Phosphate Solubilizing:
  • Solubilize insoluble inorganic phosphate compounds.
  • Examples: Pseudomonas, Bacillus, Agrobacterium, Aspergillus spp.
Compost-Making:
  • Break down organic matter into compost or humus.
  • Microorganisms involved: Bacteria, fungi, actinobacteria, protozoa, rotifers.

Cyanobacterial Biofertilizers:

  • Nitrogen-fixing biofertilizers.
  • Examples: Anabaena, Nostoc, Tolypothrix, Plectonema, Oscillatoria.
  • Symbiotic relationships: Anabaena and Nostoc with lichens, Anabaena with Azolla and Cycas.

Fungal Biofertilizers:

Mycorrhiza:
  • Fungus forming symbiotic association with roots of higher plants in humid forests.
  • Two types:
  • Ectomycorrhizae: Form mantle on root surface.
  • Endomycorrhizae: Grow within cortical cells of roots.

Benefits of Mycorrhiza:

  • Selective absorption of nutrients: P, Zn, Cu, Ca, N, Mn, Br, Fe.
  • Enhanced water uptake.
  • Hormone secretion for growth induction.
  • Protection from microbes through antibiotic secretion.
  • Classifications: Ectomycorrhizae, Eudomycorrhizae, Ectendomycorrhizae, Orchidaceous mycorrhizae, Ericoid mycorrhizae, Arbutoid mycorrhizae, Monotropoid mycorrhizae, Ophioglossoid mycorrhizae.

Biofertilizer Microorganisms:

  • Rhizobia: Nitrogen-fixing bacteria in leguminous plant root nodules, Example: R. leguminosarum for pea, R. phaseoli for beans.Azotobacter: Free-living nitrogen-fixing bacterium associated with grass and plant roots. 
  • Azospirillum: Free-living aerobic nitrogen-fixing bacterium linked with corn, wheat, and jowar roots.
  • Anabaena: Filamentous nitrogen-fixing cyanobacteria forming symbiosis with plants like Cycas and Anthoceros thallus. 
  • Azolla:Free-floating water fern containing Anabaena for nitrogen fixation.

Benefits of Biofertilizers:

  • Economical, suitable for marginal farmers.
  • Environmentally safe.
  • Improve soil fertility.
  • Biofertilizers secrete growth promoters, organic acids, proteins, and vitamins.
  • Azotobacter enriches soil with nitrogen and antibiotics.
  • Enhance soil physico-chemical properties: texture, structure, pH, water holding capacity.