Measurement of Optical Density

Ronan O'Kennedy Ronan.okennedy at
Fri Feb 17 13:18:33 EST 1995

>  the optical density of micro organisms (say E. Coli in a medium) is
>typically measured at 600nm.  Why?  Who said so?  And where did they say it?
>would be a great help if i knew,
>Dimiter I. Kurtev.
><dkurtev at>
>p.s.  mind you, i am interested in all kinds of articles concerning O.D.  :)
>p.p.s.  thankxalot.

Its dependent on the medium that you are using. 540nm is normal for Ecoli
grown on a light coloured medium like LB or M9 minimal. 600 is for darker
media like TSB.

Ronan O'Kennedy
Growth and Fermenatation Technology Lab
Dept of Microbiology
University College Galway
Phone ***-91-24411ext 2191
Fax   ***-91-25700

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