Microbiology: study of organisms (microorganisms or microbes) too small to be seen with the
naked eye.
Prokaryotes Eukaryotes Non-living Entities
Lack nucleus Has complex Reproduce only in
Lack membrane structures other living organism
bound organelles Has membrane bound Infect organisms
Bacteria, archaea organelles viruses
Fungi, protozoa,
algae
Problems Caused by Microbes
Small number of microbes are harmful, causes disease such as Malaria, Sepsis and
MRSA.
Microbes cause food spoilage and contaminate water supplies
Harmful microbes cause plant diseases, affecting;
Food production of staple
Population of migration
Microbes causes animal diseases, affecting:
Food production
Socio-economic development
Human psychology
Surra nagana
Blue tongue
Cow pox
Zoonosis: diseases that can jump into humans.
Covid-19
MERS
SARS
HIV
Ebola
Bird flu
Emerging Infectious Diseases (EID): Infectious disease whose incidence has increased recently
or could increase in near future. 12% of all human pathogens classed as EIDs. They are caused
by;
⎯ Newly identified microbes
⎯ Evolved known pathogens (influenza)
⎯ Known pathogen at new geographical site
⎯ Known pathogen believed to be under control now re-emerging as a threat
1
,Importance of Microbiology
Recycle vital elements: (C,N,O,S,P). Microbes can release locked away elements. During
photosynthesis algae/cyanobacteria uses O2 to produce carbohydrates. Fungi/bacteria
decompose organic wastes/dead plants and animals. Some bacteria ‘fix’ atmospheric
nitrogen (N2) to ammonia (NH3).
Indirectly: They are in the form of meat. Microbes in gut of ruinant animals breakdown
cellulose to generate protein.
Biotechnology: Microbes can be used to make chemicals (alcohols& solvents→ biofuels,
organic acid). They can make proteins/enzymes and drugs (therapeutics, gene
therapy).Microorganisms are used in food processing;
Food additivies/preservatives
Emulsifiers/food stabilizers/thickeners
Supplements (vitamins)
Flavoring agents
Microbes form the basis of food chain
Biological Insecticides: Microbes are pathogenic to insects seen as alternative to
chemical pesticides in preventing insect damage to agricultural crops and disease
transmission. Bacillus thuringiensis produces protein crystals toxic to insects but
harmless to other animals and to plants.
Bioremediation: Using microbes/ microbial enzymes to clean up pollutants and toxic
waste. Some bacteria use pollutants as energy/carbon source other bacteria produce
enzymes to breakdown toxic waste. These enzymes are used in drain cleaners. Microbes
and enzymes are used to remove toxins from chemical spills and toxic waste sites.
Sewage treatment: Using microbes to recycle water. Sewage is a major pollutant
composed of human wastes 99.9% water+ small amount of suspended solids. Sewage
treatment plants remove undesirable materials/harmful microbes.
1. Removal of large solids by filters, setting tanks.
2. Remaining liquid/ organic materials are converted by
bacteria into by-products.
Environment of Microorganisms
Microorganisms are ubiquitous. Meaning → Microorganisms exist in interacting
that they live in all types of ecological populations called microbial communities or
niches. microbiomes.
2
, → The environment in which a microbial population lives is its habitat (including hot vents, soil,
marine and our body)
Ecosystem: the microbe+ physical and chemical constituents in the environment
Microbial Ecology: the study of microbes in their natural environment.
*Diversity and abundance of microbes in a
microbiome is controlled by resources (foods) Microbes in a community can:
and conditions (temperature ,pH content etc). Interact with each other.(cooperation
& competition)
Interact with their chemical and
physical environment (resources are
utilized, waste product release,
environmental conditions)
Microbiomes are Dynamic
(Expand, contract,change)
O2 is essential to some microbes but a poison to others. O2 consuming
microbes remove O2 from habitat. Habitat becomes anoxic (O2-free)
conditions favor the growth of anaerobic microbes (these microbes were
present in the habitat but unable to grow)
Microbes attach to each other and to surfaces grow into masses called biofilms. Occurs on
rocks, pipes , teeth and medical implants. Biofilms can protect mucous membranes from
harmful microbes. They can clog medical implants joint prostheses and catheters. Cause
infective endocarditis (damages heart valves)
Biofilms are often resistant to antibiotics.
Microbiome normally present in and on the human body are called normal microbiota (or
microflora or human microbiome)
Benefits of Human Microbiome:
⎯ Prevents growth of pathogens.
⎯ Produce growth factors such as folic acid and vitamin K.
Sometimes human microbiomes can
make us sick or infect others.
3
, Metabolic Diversity
Some microbes can sustain themselves on inorganic substances by using pathways that
are unavailable to either plants or animals.
All organisms, including microbes, can be classified metabolically according to their
nutritional pattern- their source of energy and source of carbon.
a) Phototrophs→ use light as primary energy source.
b) Chemotrophs→ depend on oxidation- reduction reactions of inorganic or organic
compounds for energy.
⎯ Autotrophs: self-feeders. Lithotrophs (rock eating)
⎯ Heterotrophs: feeders on others. Organotrophs
Nutritional Classifications *Each photosynthetic prokaryote is classified
according to the way it reduces CO2.
a) Photoautotrophs
b) Photoheterotrophs *These bacteria can’t use H2O to reduce CO2,
c) Chemoautotrophs they can’t carry on photosynthesis when O2 is
d) Chemoheterotrophs present. They must have an anaerobic
environment.
Anoxygenic: when a photosynthetic process does
not produce O2. Anoxygenic photoautotrophs are
green and purple bacteria.
Nutritional Type Energy Source Carbon Source Example
Photoautotroph light CO2 Oxygenic: plants,
cyanobacteria
Anoxygenic:
green/purple bacteria
Photoheterotroph Light Organic Compounds Green bacteria,
purple nonsulfur
bacteria
Chemoautotroph Chemical CO2 Iron-oxidizing
bacteria
Chemoautotroph Chemical Organic Compounds Animals, fungi,
fermentative bacteria
Green Bacteria:
They use sulfur, sulfur compounds (H2S) or hydrogen gas to reduce CO2 and from
organic compounds.
They oxidize sulfide (S2-) or sulfur (S) to sulfate (SO42-) or oxidize H2O.
4
naked eye.
Prokaryotes Eukaryotes Non-living Entities
Lack nucleus Has complex Reproduce only in
Lack membrane structures other living organism
bound organelles Has membrane bound Infect organisms
Bacteria, archaea organelles viruses
Fungi, protozoa,
algae
Problems Caused by Microbes
Small number of microbes are harmful, causes disease such as Malaria, Sepsis and
MRSA.
Microbes cause food spoilage and contaminate water supplies
Harmful microbes cause plant diseases, affecting;
Food production of staple
Population of migration
Microbes causes animal diseases, affecting:
Food production
Socio-economic development
Human psychology
Surra nagana
Blue tongue
Cow pox
Zoonosis: diseases that can jump into humans.
Covid-19
MERS
SARS
HIV
Ebola
Bird flu
Emerging Infectious Diseases (EID): Infectious disease whose incidence has increased recently
or could increase in near future. 12% of all human pathogens classed as EIDs. They are caused
by;
⎯ Newly identified microbes
⎯ Evolved known pathogens (influenza)
⎯ Known pathogen at new geographical site
⎯ Known pathogen believed to be under control now re-emerging as a threat
1
,Importance of Microbiology
Recycle vital elements: (C,N,O,S,P). Microbes can release locked away elements. During
photosynthesis algae/cyanobacteria uses O2 to produce carbohydrates. Fungi/bacteria
decompose organic wastes/dead plants and animals. Some bacteria ‘fix’ atmospheric
nitrogen (N2) to ammonia (NH3).
Indirectly: They are in the form of meat. Microbes in gut of ruinant animals breakdown
cellulose to generate protein.
Biotechnology: Microbes can be used to make chemicals (alcohols& solvents→ biofuels,
organic acid). They can make proteins/enzymes and drugs (therapeutics, gene
therapy).Microorganisms are used in food processing;
Food additivies/preservatives
Emulsifiers/food stabilizers/thickeners
Supplements (vitamins)
Flavoring agents
Microbes form the basis of food chain
Biological Insecticides: Microbes are pathogenic to insects seen as alternative to
chemical pesticides in preventing insect damage to agricultural crops and disease
transmission. Bacillus thuringiensis produces protein crystals toxic to insects but
harmless to other animals and to plants.
Bioremediation: Using microbes/ microbial enzymes to clean up pollutants and toxic
waste. Some bacteria use pollutants as energy/carbon source other bacteria produce
enzymes to breakdown toxic waste. These enzymes are used in drain cleaners. Microbes
and enzymes are used to remove toxins from chemical spills and toxic waste sites.
Sewage treatment: Using microbes to recycle water. Sewage is a major pollutant
composed of human wastes 99.9% water+ small amount of suspended solids. Sewage
treatment plants remove undesirable materials/harmful microbes.
1. Removal of large solids by filters, setting tanks.
2. Remaining liquid/ organic materials are converted by
bacteria into by-products.
Environment of Microorganisms
Microorganisms are ubiquitous. Meaning → Microorganisms exist in interacting
that they live in all types of ecological populations called microbial communities or
niches. microbiomes.
2
, → The environment in which a microbial population lives is its habitat (including hot vents, soil,
marine and our body)
Ecosystem: the microbe+ physical and chemical constituents in the environment
Microbial Ecology: the study of microbes in their natural environment.
*Diversity and abundance of microbes in a
microbiome is controlled by resources (foods) Microbes in a community can:
and conditions (temperature ,pH content etc). Interact with each other.(cooperation
& competition)
Interact with their chemical and
physical environment (resources are
utilized, waste product release,
environmental conditions)
Microbiomes are Dynamic
(Expand, contract,change)
O2 is essential to some microbes but a poison to others. O2 consuming
microbes remove O2 from habitat. Habitat becomes anoxic (O2-free)
conditions favor the growth of anaerobic microbes (these microbes were
present in the habitat but unable to grow)
Microbes attach to each other and to surfaces grow into masses called biofilms. Occurs on
rocks, pipes , teeth and medical implants. Biofilms can protect mucous membranes from
harmful microbes. They can clog medical implants joint prostheses and catheters. Cause
infective endocarditis (damages heart valves)
Biofilms are often resistant to antibiotics.
Microbiome normally present in and on the human body are called normal microbiota (or
microflora or human microbiome)
Benefits of Human Microbiome:
⎯ Prevents growth of pathogens.
⎯ Produce growth factors such as folic acid and vitamin K.
Sometimes human microbiomes can
make us sick or infect others.
3
, Metabolic Diversity
Some microbes can sustain themselves on inorganic substances by using pathways that
are unavailable to either plants or animals.
All organisms, including microbes, can be classified metabolically according to their
nutritional pattern- their source of energy and source of carbon.
a) Phototrophs→ use light as primary energy source.
b) Chemotrophs→ depend on oxidation- reduction reactions of inorganic or organic
compounds for energy.
⎯ Autotrophs: self-feeders. Lithotrophs (rock eating)
⎯ Heterotrophs: feeders on others. Organotrophs
Nutritional Classifications *Each photosynthetic prokaryote is classified
according to the way it reduces CO2.
a) Photoautotrophs
b) Photoheterotrophs *These bacteria can’t use H2O to reduce CO2,
c) Chemoautotrophs they can’t carry on photosynthesis when O2 is
d) Chemoheterotrophs present. They must have an anaerobic
environment.
Anoxygenic: when a photosynthetic process does
not produce O2. Anoxygenic photoautotrophs are
green and purple bacteria.
Nutritional Type Energy Source Carbon Source Example
Photoautotroph light CO2 Oxygenic: plants,
cyanobacteria
Anoxygenic:
green/purple bacteria
Photoheterotroph Light Organic Compounds Green bacteria,
purple nonsulfur
bacteria
Chemoautotroph Chemical CO2 Iron-oxidizing
bacteria
Chemoautotroph Chemical Organic Compounds Animals, fungi,
fermentative bacteria
Green Bacteria:
They use sulfur, sulfur compounds (H2S) or hydrogen gas to reduce CO2 and from
organic compounds.
They oxidize sulfide (S2-) or sulfur (S) to sulfate (SO42-) or oxidize H2O.
4
