Why we take the optical density of bacteria at 600 nm generally. what is the basic concept behind it?
Cell suspensions are turbid. Cells absorb and scatter the light. The higher the cell concentration, the higher the turbidity. Spectrophotometerscan measure intensity of light very accurately. The cell culture is placed in a transparent cuvette and the absorption is measured relative to medium alone. Optical density (OD) is directly proportional to the biomass in the cell suspension in a given range that is specific to the cell type. Using spectrophotometry for measuring the turbidity of cultures is known as turbidometry.
This has made spectrophotometry the methods of choice for measurements of bacterial growth and related applications. Spectrophotometry's drawback is its inability to provide an absolute count or distinguish between living and dead c
Optical density is usually taken to measure the growth concentration of your growing bacteria. This method is completely based on beer and lambert's law. It is not necessary to take OD only at 600nm. The lambda max is dependent on the medium you use. Check the absorbance of your medium at each wavelength and decide your lambda max. Based on which you should check the OD of your bacteria
The basic concept is "spectrophotometer measures turbidity of broth' according to which number of bacteria in the broth can be predicted. It is always suggested to verify your absorbance result with plate count at least once before your experiment. Detail can be found in http://www.mpi-bremen.de/Binaries/Binary13037/Wachstumsversuch.pdf
Cell suspensions are turbid. Cells absorb and scatter the light. The higher the cell concentration, the higher the turbidity. Spectrophotometerscan measure intensity of light very accurately. The cell culture is placed in a transparent cuvette and the absorption is measured relative to medium alone. Optical density (OD) is directly proportional to the biomass in the cell suspension in a given range that is specific to the cell type. Using spectrophotometry for measuring the turbidity of cultures is known as turbidometry.
This has made spectrophotometry the methods of choice for measurements of bacterial growth and related applications. Spectrophotometry's drawback is its inability to provide an absolute count or distinguish between living and dead c
as the others mentioned it depend on the turbidity but the measurment can be done at not only 600 nm
according to the malty experimenter doing, the range of density of bacteria that make the turbidity, the composition of the bacteria and the product may be cause little effect, the size of bacteria all this may effect on absorption and on Spectrophotometerscan measure intensity
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