FeCl3 causes massive precipitation in M9 - (May/25/2009 )

hi guys,

IN this paper ( see attached) the author mentioned adding Fecl3 to final conc. of 1.5mM.

however when i add this to the M9 media i prepared, i notice a serious precipitation that actually cause my agar to be " blurry" full of small white stuff.

Is there a way to prevent this from happening?

Yup indeed it's the FeCl3 messing around. Seems to be reacting with probably the phosphate buffer. Anyway, I emailed the author and apparently her minimal media is not M9 but similar though. The key ingredient in the recipe is nitrilotriacetic acid.

Since my lab doesn' t have this chemical. I decided to add approx equimolar of EDTA (vs FeCl3) to the M9 media. And things seem to work out well. Chelation of Fe3+ seems to be important for the assay to work. It's more sensitive now.