JCM 1067 . FRESHWATER IRON-OXIDIZING BACTERIA MEDIUM-II

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Equipment needed: Autoclave Filter

Final pH: n.d.

Select a strain (optional):

ml
Compound Amount Unit
FeS solution 50.00 ml
Modified Wolfe's mineral solution 50.00 ml
Agar , Noble
(BD-Difco)
1.50 g
1 Top layer:
Modified Wolfe's mineral solution 1000.00 ml
Trace minerals 10.00 ml
2 After cooling of the top layer solution, add per liter the following solutions (filter-sterilized):
Trace vitamins 10.00 ml
NaHCO3
(8%)
5.25 ml
3 Bottom layer:
4 Autoclave both layer solutions. Shortly after autoclaving, pipette the bottom layer into each culture vessel (typically 5 ml in 60 ml glass vials, use pipette tips that have been cut to enlarge the opening). The bottom layer is allowed to cool for at least 30 min to ensure its solidification.
5 Add the top layer solution in 5 to 6 times the volume of the bottom layer to the culture vessels containing the bottom layer (e.g., 25 to 30 ml in 60 ml glass vials with 5 ml of the bottom layer).
6 Then, cap the culture vessels with silicone rubber stoppers, and replace the gas phase with a N2-CO2 (4:1, v/v) gas mixture.
7 Comment: The medium can be stored in culture vessels for a certain time by capping with butyl rubber stoppers, instead of silicon rubber stoppers and keeping anoxic in the vessels. Silicone rubber stopper is O2 permeable and creates a mircoaerophilic condition in the culture vessels.

FeS solution #

300
Compound Amount Unit
FeSO4 x 7 H2O 46.2 g
Na2S x 9 H2O 39.6 g
Distilled water 300.0 ml
1 Prewarm distilled water at 50C in a beaker with a stir bar. While rapidly starring the water, add FeSO4 x 7H2O, followed immediately by Na2S x 9H2O. A thick black precipitate will form instantly. Stir continuously for 2 to 3 min. Remove the mixture to a narrow-mouthed glass bottle (500 ml) that can be tightly stopped. The bottle is filled to the top with distilled water and capped. Allow to settle for several hours, decant and replace the overlaying water. Repeat this procedure at least five times to wash the FeS precipitate. Check pH to be close to neutral. To stock the FeS solution, fill the bottle with distilled water and cap. Remove the overlaying water when prepare the bottom layer.

Modified Wolfe's mineral solution #

1000
Compound Amount Unit
NH4Cl 1.00 g
MgSO4 x 7 H2O 0.20 g
CaCl2 x 2 H2O 0.10 g
KH2PO4 0.05 g
Distilled water 1000.00 ml

Trace minerals #

1000
Compound Amount Unit
Nitrilotriacetic acid 1.50 g
MgSO4 x 7 H2O 3.00 g
MnSO4 x n H2O 0.50 g
NaCl 1.00 g
FeSO4 x 7 H2O 0.10 g
CoSO4 x 7 H2O 0.10 g
CaCl2 x 2 H2O 0.10 g
ZnSO4 x 7 H2O 0.10 g
CuSO4 x 5 H2O 0.01 g
AlK(SO4)2 0.01 g
H3BO3 0.01 g
Na2MoO4 x 2 H2O 0.01 g
Distilled water 1000.00 ml
1 Dissolve nitrilotriacetic acid and adjust pH to 6.5 with KOH solution. Then proceed to add minerals. Adjust final pH to 7.0.