Dry weight of a culture sample

Definition

Dry weight of a culture sample is the mass of microbial cells after removing all water content. It provides an accurate measure of cell biomass in a culture.

5 Must Know Facts For Your Next Test

1. Dry weight measurement is a direct method to quantify microbial growth.
2. The process involves filtering, drying, and weighing the culture sample.
3. It eliminates variability caused by differences in water content between samples.
4. This method is particularly useful for filamentous microorganisms and biofilms.
5. Accuracy can be influenced by residual salts and medium components remaining after drying.

Review Questions

• What steps are involved in determining the dry weight of a culture sample?
• Why is dry weight measurement considered more accurate than optical density for certain microorganisms?
• How can residual medium components affect the accuracy of dry weight measurements?

Related terms

Optical Density (OD): A measure of how much a microbial culture absorbs light, used to estimate cell concentration.

Colony Forming Units (CFU): A count of viable bacteria or fungal cells that form colonies on solid media.

Biomass: The total mass of living microorganisms present in a given volume or area.