1. Influence of Chemical and Physical Factors in Environment
Microbial Growth
Influence of Chemical and Physical Factors in Environment

2. I. Objectives How do bacteria grow?
What is generation time and how do we plot this
How do we measure this
What are the requirements for growth?
How do we provide these requirements?

3. II. How do they grow?
A. Culturing microbes
Batch method
Continuous

4. B. Mechanics of Growth
1. Binary fission
2. Four phases

5. 3. Plotting growth curves
Generation time
Plotting exponential growth

6. 4. Mathematical Calculation
Growth equation: n = log N - No / 0.301
So, can calculate generation time:

7. 5. Phases of growth

8. C. Measurement of Growth
1. Direct
a. plate count (viable)

9. b. Direct microscopic count

10. c. Other direct methods for special cases
Dilute samples

11. Growth not possible on solid media

12. 2. Indirect methods
a. Turbidity
b. Metabolic activity
c. Dry weight

13. III. Environmental factors affecting growth

14. A. Temperature effects

15. 1. Cardinal temperatures

16. 2. Microbial adaptations to temperature
Typical bacteria
Others:

17. 3. Physiological and structural adaptations

18. B. Effect of pH
What is pH
Types of bacteria

19. C. Osmotic requirements

20. D. Effects of oxygen on growth
1. Terminology

21. 2. Why obligate anaerobes?

22. 3. Culture techniques
Aerobes
Anaerobes

23. IV. Media requirements
A. Major macronutrients

24. B. Minor macronutrients and trace elements

25. C. Types of media

26. V. Once we can grow them. . .