1 / 21

The Growth of Bacterial Cultures

The Growth of Bacterial Cultures. Ways of monitoring and measuring growth, directly and indirectly. Reproduction in Prokaryotes. Bacteria normally reproduce through Binary fission

lynsey
Download Presentation

The Growth of Bacterial Cultures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Growth of Bacterial Cultures • Ways of monitoring and measuring growth, directly and indirectly

  2. Reproduction in Prokaryotes • Bacteria normally reproduce through Binary fission • There are a few bacterial species that reproduce through Budding,Conidiospores (actinomycetes), or by Fragmentation

  3. Binary Fission Figure 6.11

  4. Generation Time -Time required for cell to divide (and its population to double) Figure 6.12b

  5. Why we use logarithmic graphing for bacterial growth Figure 6.13

  6. Calculations • If 5 cells were allowed to divide 9 times Then, 5 x 29 = 2560 cells • To calculate the number of generations, you need to convert into logarithms. The log of 2 (0.301) is used because one cell divides into two Refer to Appendix D of your textbook

  7. If 100 cells growing for 5 hours produced 1,720,320 cells: = log 1,720,320 – log 100 = 6.2356 - 2 =14 generations 0.301 0.301 = 60 minutes x 5 hours = 21minutes/generation 14 generations *These calculations are useful to compare growth conditions

  8. Phases of Growth Figure 6.14

  9. Direct Measurements of Microbial Growth • Plate Counts • Filtration • Direct Microscopic Count

  10. Direct Measurements of Microbial Growth • Plate Counts: Perform serial dilutions of a sample Figure 6.15, top portion

  11. Plate Count • Inoculate Petri plates from serial dilutions Figure 6.16

  12. Plate Count • After incubation, count colonies on plates that have 25-250 colonies (CFUs) Bacterial Lawn Figure 6.15

  13. Cell Viability Measurement: Spread Plate Optimal number to count is 30-300 colonies

  14. Direct Measurements of Microbial Growth • Filtration Figure 6.17a, b

  15. Direct Measurements of Microbial Growth • Multiple tube MPN test • Count positive tubes and compare to statistical MPN table. Figure 6.18b

  16. Direct Measurements of Microbial Growth Figure 6.19

  17. Direct Measurements of Microbial Growth • Direct Microscopic Count

  18. Indirect Measurements of Microbial Growth • Turbidity • Metabolic Activity • Dry weight

  19. Estimating Bacterial Numbers by Indirect Methods • Turbidity Figure 620

  20. Optical Density Measurement 600nm to measure Pichia growth

  21. Estimating Bacterial Numbers by Indirect Methods • Metabolic Activity -measure product as a function of time Example: Bacterial culture produces acid as a metabolic product, therefore you can monitor growth by monitoring change in pH over time. • Dry weight-filter all cells, dry in desiccator, and weigh on scale

More Related