Mycobacterium smegmatis growth characteristics - (Feb/12/2016 )

I am working with M.smegmatis, i need to know the relation between OD600 values and CFU/ml (concentration) for M.smegmatis. Can any one kindly provide a good reference and let me know.

Normally you would prepare a serial dilution of your growth culture (10-5,10-6,10-7 etc), spread plate these (100ul) to solid media (Middlebrook 7H10 for M.smeg) and count colonies. Accounting for your dilutions should give you CFU/ml.

However, M.smeg is a bit trick in liquid and solid media due to "crunchyness" phenotype and flaky clumps. Usually the addition of tween 80 to the liquid media prevents this and will allow a more uniform culture growth.This should be easier to work with then.

As for a reference paper :http://www.ncbi.nlm.nih.gov/pmc/articles/PMC103559/

They also mention here that the addition of tween80 also alters the nutritional components of your media as M.smeg  can hydrolyze this as a carbon source. Just something to keep in mind if you are comparing different media.