1. بسم الله الرحمن الرحيم بسم الله الرحمن الرحيم GROWTH AND NUTRITION OF BACTERIA Prof. Khalifa Sifaw Ghenghesh Dept. of Medical Microbiology, Faculty of Medicine, Tripoli University Tripoli - Libya

2.   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. 1.Lag Phase 2. 2.Log (logarithmic) Phase 3. 3.Stationary Phase 4. 4.Death Phase

3. 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. 1.Photo-autotrophs: 2. 2.Chemo- autotrophs 3. 3.Heterotrophs:

4. OXYGEN REQUIREMENTS AND METABOLISM: 1. 1.Obligate Aerobes 2. 2.Obligate Ananerobes 3. 3.Facultative Anaerobes 4. 4.Microaerophilic Bacteria. MEDIA FOR BACTERIAL GROWTH: 1. 1.General Laboratory Media: – –Peptone >> Amino acids – –Growth factors and inoorganic salts – –NaCl 2. 2.Synthetic Media 3. 3.Special Media: – –Selective media – –Indicator media – –Enrichment media

5. PHYSICAL CONDITIONS REQUIRED FOR GROWTH 1. 1.Influence of Oxygen and CO: 2. 2.Influence Temperature: – –On Growth:   Mesophilic bacteria   Psychrophilic bacteria   Thermophilic bacteria – –On Viability: 3. 3.Influence of Moisture and Desiccation:

6. 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: