1. Environmental Biology for Engineers and Scientists D.A. Vaccari, P.F. Strom, and J.E. Alleman © John Wiley & Sons, 2005 Chapter 11 – Quantifying Microorganisms

2. Figure 11 ‑ 1. Elemental Distribution of Microbial Biomass Relative to the Hydrosphere, Lithosphere, and Atmosphere

3. Figure 11 ‑ 2. Modern Compound Light Microscope. This model includes a fluorescence attachment and a camera

4. Figure 11 ‑ 3. Bright-Field Microscopy. Original image viewed against a light/bright background

5. Figure 11 ‑ 4. Dark-Field Microscopy. Bright reflected image is viewed against a darkened/black background

6. Figure 11 ‑ 5. Phase-Contrast Microscopy. Object a), with high refractive index (n), bends and retards the light more; after further retardation at the edges of the phase plate, the recombined light (retarded and unretarded) creates destructive interference, leading to a darker appearance. Object b), with a low n, does not bend or retard the light, creating no interference, and thus appears bright. Thus contrast was created between the two nearly transparent objects that was not otherwise visible. A special condenser (not shown) with a phase ring is also required

7. Figure 11 ‑ 6. Fluorescence Microscopy. Fluorescent image is viewed against a darkened/black background.

8. Figure 11 ‑ 7. Stage micrometer used to calibrate dimensions under microscope

9. Figure 11 ‑ 8. Resolution with Various Microscopes. Electron microscopes include scanning (SEM), transmission (TEM), and scanning tunneling (ST) or scanning probe (SP)

10. Figure 11 ‑ 9. Petroff-Hauser Counting Cell

11. Figure 11 ‑ 10. Filling a Sedgewick-Rafter Cell

12. Figure 11 ‑ 11. Spread Plating

13. Figure 11 ‑ 12. Membrane Filtration

14. Figure 11 ‑ 13. MPN Method Schematic. Positive tubes shown as dark after incubation

15. Figure 11 ‑ 14. Bacteriophage Plaques

16. Figure 11 ‑ 15 Example of Respirometry Data. Oxygen uptake with various grades (reagent, technical, lean and rich) of monoethanol amine (MEA).

17. Figure 11 ‑ 16 Biometer flasks

18. Figure 11 ‑ 17. Example of System for Anaerobic Gas Production Measurement

19. Figure 11 ‑ 18. Theoretical Microbial Growth Schematic

20. Figure 11 ‑ 19. Representative Microbial Generation Times under Optimal Conditions

21. Figure 11 ‑ 20. Theoretical Stair-Stepped Batch Bacterial Growth Curve

22. Figure 11 ‑ 21. Semi-log Plot of Exponential Growth

23. Figure 11 ‑ 22. Typical Batch Bacterial Growth Curve

24. Figure 11 ‑ 23. Monod Kinetics

25. Figure 11 ‑ 24. Batch Growth Curve Using Equation 11-11, with  max = 10/day, Ks = 5 mg/L, Y = 0.6 (explained below), b = 0.1/day, and the starting values of S and X = 120 and 5 mg/L, respectively

26. Figure 11 ‑ 25. Schematic of a Continuous Culture System

27. Figure 11 ‑ 26. Schematic of a Chemostat

28. Figure 11 ‑ 27. Substrate Minimum and Washout in a Chemostat

29. Figure 11 ‑ 28. Example Theoretical Plots of S~ and X~ vs. D in a Chemostat. Values used in Equations 11-28 and 11-29 were  max = 10/day, Ks = 5 mg/L, b = 0.05/day, Y = 0.5, and Si = 200 mg/L

30. Figure 11 ‑ 29. Lineweaver-Burk Plot. In a) the same coefficients are used as in Figure 11-28 to generate the theoretical curves. In b) the value of b = 0.15, showing its effect on the non-linearity of the 1/D plot

31. Figure 11 ‑ 30. Example of Determining Y and b. The same coefficients were used to generate the plot as in Figure 11-28, except b = 0.15

32. Figure 11 ‑ 31. Dependence of Microbial Growth on Temperature for a Hypothetical Mesophile

33. Figure 11 ‑ 32. Example of Andrews Model of Substrate Inhibited Growth