‫بسم هللا الرحمن الرحيم‬
GROWTH AND NUTRITION
OF BACTERIA
Prof. Khalifa Sifaw Ghenghesh
Dept. of Medical Microbiology,
Faculty of Medicine, Tripoli University
Tripoli - Libya
 Growth: An Orderly Increase in All components of an Organism
– Multiplication >> Binary Fission.
 Measurement of Growth:
– Increase in Numbers
– Increase in Mass
 Batch Culture:
– Growth Curve:
 A Total Count.
 A Viable Count.
1. Lag Phase
2. Log (logarithmic) Phase
3. Stationary Phase
4. Death Phase
GROUTH REQUIREMENTS AND BACTERIAL NUTRITION:
 Suitable Nutrients Must Be Supplied
 Physical Conditions Must Be as Near as Possible for
the Organism Under Consideration
BACTERIAL METABOLISM:
Bacteria Require:
 An Energy Source
 A Carbon Source
 A Nitrogen Source
 Other Inorganic Salts and Accessory Growth Factors.
1. Photo-autotrophs:
2. Chemo- autotrophs
3. Heterotrophs:
OXYGEN REQUIREMENTS AND METABOLISM:
1. Obligate Aerobes
2. Obligate Ananerobes
3. Facultative Anaerobes
4. Microaerophilic Bacteria.
MEDIA FOR BACTERIAL GROWTH:
1. General Laboratory Media:
– Peptone >> Amino acids
– Growth factors and inoorganic salts
– NaCl
2. Synthetic Media
3. Special Media:
– Selective media
– Indicator media
– Enrichment media
PHYSICAL CONDITIONS
REQUIRED FOR GROWTH
1. Influence of Oxygen and CO:
2. Influence Temperature:
– On Growth:



Mesophilic bacteria
Psychrophilic bacteria
Thermophilic bacteria
– On Viability:
3. Influence of Moisture and Desiccation:
4. Influence of Hydrogen Ion Concentration
(pH):
5. Influence of Light and other radiations:
6. Influence of Osmotic Pressure:
7. Influence of Mechanical and Sonic Stresses: