Component	Stock	Volume for 500ml of 1X	Final Concentration
10X MOPS Stock	see above	50 ml	see above
Deionized water	N/A	400 ml	N/A
Carbon sourceb	1 M	10 ml	20 mM
CaCl2 c	53 mM	300 μl	32 μM
K2SO4	27.5 mM	5 ml	0.29 mM
K2HPO4	172.8 mM	5 ml	1.32 mM
FeCl2c	8 mM	500 μl	8 μM

^aIt is possible to make the 1x from sterile stock solutions with good aseptic technique. However, this final filtration step eliminates potential contamination issues from long-term stocks and is good practice particularly when studying mutants that may grow slower than wild-type for a given carbon source.

^bWe use most carbon sources at 20 mM. Depending on the quality and solubility of the carbon source tested, vary the concentration accordingly. A standard test for a carbon source of unknown quality and/or toxicity is to measure growth on 1, 5, 20, and 50 mM.

^cThese two additions have been made to stimulate biofilm formation on biotic surfaces (CaCl₂) and increase growth rate and yield on substrates requiring metabolism by iron-containing oxidases (FeCl₂). They are not required for growth on glucose and they are not part of the media from the original citation.