The document summarizes microbial growth requirements and culture techniques. It discusses the temperature, pH, oxygen, pressure, and nutritional requirements for microbial growth. It also describes different types of culture media such as selective, differential and enrichment media. Various culture methods are outlined, including anaerobic culturing and preserving cultures through lyophilization or deep freezing.

1. Chapter 5 Microbial Nutrition and Culture cont’d Siti Sarah Jumali (ext 2123) Room 3/14 [email_address]

7. Food Preservation Temperatures

9. Patterns of Oxygen Use

12. Plasmolysis

14. Responses to Salt

15. The Great Salt Lake in Utah

25. Types of Culture Media Type of Media Purpose Chemically Defined Growth of chemoheterotrophs and photoautotrophs: microbiological assays Complex Growth of most chemoheterotrophic organisms Reducing Growth of obligate anO2 Selective Suppresion of unwanted microbes; encouraging desired microbes Differential Differentiation of colonies of desired microbes from others Enrichment Similar to selective media but designed to increase numbers of desired microbes to detectable levels.

31. Three species of Candida can be differentiated in mixed culture when grown on CHROMagar Candida plates

32. Identification of urinary tract pathogens with differential media (CHROMagar)

36. The Streak Plate Method uses agar plates to prepare pure cultures

37. The Streak Plate Method Figure 6.11

39. Anaerobic Jar Figure 6.6

40. To culture obligate anaerobes, all molecular oxygen must be removed and kept out of medium. Agar plates are incubated in sealed jars containing chemical substances that remove oxygen and generate carbon dioxide or water

41. Anaerobic Transfer

42. An Anaerobic Chamber Figure 6.7

45. CHAPTER 6: MICROBIAL GROWTH

47. Binary Fission

48. Binary Fission

49. Thin section of the bacterium Staphylococcus , undergoing binary fission

50. Budding in Yeast

55. Synchronous growth : A hypothetical situation in which the number of cells in a culture would increase in a stair-step pattern, dividing together at the same rate Nonsynchronous growth : A natural situation in which an actual culture has cell dividing at one rate and other cells dividing at a slightly slower rate

57. Microbes growing continuously in a chemostat

60. Plate Counts Figure 6.17

62. 2) Counting Bacteria by Membrane Filtration

65. The Petroff-Hausser Counting Chamber

66. Direct Microscopic Count

67. Counting colonies using a bacterial colony counter

68. Bacterial colonies viewed through the magnifying glass against a colony-counting grid

69. Which of these plates would be the correct one to count? Why? Countable number of colonies (30 to 300 per plate )

71. Turbidity

72. Turbidity The less light transmitted, the more bacteria in sample.

75. Biosafety Level 4 (BSL-4) Laboratory

76. Questions?