Download lecture notes-microbiology-1

Analysis of Biological System
An understanding of biological system can be
simplified by analyzing the system at several
different levels:
• Cell level: microbiology, cell biology;
• Molecular level: biochemistry, molecular biology;
• Population level: microbiology, ecology;
• Production level: bioprocess.
Course Outline
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Overview of Microbiology
Biochemistry of Cells
Enzyme Technology
Molecular Biology and Metabolic Pathways
Microbial Growth Models
Bioreactor Analysis and Operation
Downstream Processing (product recovery and
purification)
• Genetic Engineering
Overview of Microbiology
• Microbiology (in Greek micron = small and
biologia = studying life) is the study of
microorganisms at the cell level.
• Microorganism refers to any organism too
small to be viewed by the unaided eye, as
bacteria, fungi and algae and protozoa.
(Random House Webster’s Unabridged Dictionary)
It is often illustrated using single-celled, or
unicellular organisms
Overview of Microbiology
(Chapter 2, M. Shuler)
Cell:
• The cell is the basic unit of life.
• Cells are packages of living matter surrounded
by membranes or walls.
• Within the cell are various organelles
in controlling life processes
for the cell intake of nutrients, production of energy,
discharge of waste materials, and reproduction.
Basics of Microbiology
• Naming cells
• Primary classification of microorganism
- Procaryotes: bacteria;
- Eucaryotes: fungi (yeast and mold)
algae
- Virus
• Microbial cell characteristics under each cell
category
- cell structure and reproduction
Naming Cells
A dual name (binary nomenclature) in Latin or
Latinized is used, including
genus & species
A genus: a group of related species
A species: includes organisms that are substantially alike.
e.g. Escherichia coli; Bacillus subtilis; Sacchromyces cerevisiae;
Penicillium chrysogenum. (in italic type)
Escherichia is the genus, the first letter is capitalized
coli is the species in lower case.
Abbreviation:
E. coli
Various strain and substrains are designated by the addition of letters and
numbers.
e.g. E. coliK12.
Microbial diversity
Cell adaptation to the environment
Temperature
• Psychrophiles can grow below 20oC.
e.g. Leifsonia rubra isolated from Antarctica.
• Mesophiles grow between 20-50oC.
important uses in food preparation such as cheese, yoghurt,
beer and wine making, e.g. Saccharomyces cerevisiae.
• Thermophiles can grow at temperature higher than 50oC.
Thermus aquaticus is a species of bacterium that can tolerate high
temperatures. It thrives at 70° C, but can survive at temperatures 50°80° C .
Regular sterilization at 121oC.
Microbial diversity
pH:
– Acidophiles are microbes that tends toward
acidic conditions pH< 3.
e.g Acidithiobacillus ferrooxidans in
acid mine drainage.
– Alkaliphiles are microbes that thrive in alkaline
environments with a pH of 9 to 11.
e.g. Bacillus okhensis living in
carbonate soil.
Microbial diversity
Moisture:
Some cells can grow
- where the water activity is high (e.g.
algae)
- on solid surface (mold)
Microbial diversity
Oxygen:
• Some microorganism requires oxygen for growth called
aerobic.
• Other organism can be inhibited by the presence of
oxygen which is called anaerobic.
• Facultative organism can switch the metabolic pathway
to allow them to grow under either circumstance.
e.g. Saccharomyces cerevisiae.
Almost all animals, most fungi and several bacteria are
aerobes.
Most anaerobic organism are bacteria.
Microbial diversity
Nutrient sources:
Microorganism can be classified into two categories on the
basis of their carbon sources.
• Heterotrophs use organic compounds such as
carbohydrates, lipids, and hydrocarbons as a carbon and
energy source.
• Autotrophs use carbon dioxide as a carbon source.
e.g. cyanobacteria
Microbial diversity
Extremophiles:
Organism from those extreme environments.
• Acidophile: An organism with an optimum pH level at or below pH 3.
• Alkaliphile: An organism with optimal growth at pH levels of 9 or
above.
• Halophile: An organism requiring at least 0.2M of NaCl for growth.
• Psychrophile: An organism that can thrive at temperatures of 20 °C
or lower.
• Thermophile: An organism that can thrive at temperatures between
60-80 °C.
Microbial diversity
Shape:
• coccus (cocci, pl): A cell with a spherical or
elliptical shape.
e.g. Streptococcus is a genus of spherical bacteria
http://www.beyondbooks.com/lif72/2a.asp
Microbial diversity
• bacillus (bacilli, pl): a cylindrical cell
e.g. Bacillus subtilis is a bacterium that is commonly
found in soil.
Microbial diversity
• spirillum (spirilla, pl): a spiral-shaped cell.
e.g. Rhodospirillum is a bacterium.
Some cells may change shape in response to changes
in their local environment.
Section Summary
• Organism cells are highly diverse in terms
of their adaptation to the living
environment:
Temperature, pH, oxygen, moisture,
nutrients
• Shapes (bacteria): Coccus, Bacillus and
Spirillum