Authors: Mark Dopson & Stephan Christel

### Abstract

Medium for growth of extreme acidophilic microorganisms. This medium does not contain trace elements. When not working on mineral, addition of trace element (TE) solution is necessary, see separate protocol. http://www.nature.com/protocolexchange/protocols/3811

### Reagents 

**Medium**:

1. Ammonium sulfate, (NH4)2SO4
- Sodium sulfate decahydrate, Na2SO4 x10H2O
- Potassium chloride, KCl
- Potassium hydrogen phosphate, K2HPO4
- Magnesium sulfate heptahydrate, MgSO4 x7H2O
- Calcuim nitrate, Ca(NO3)2

**General**:

1. Sulfuric acid
- Sodium hydroxide

### Equipment

1. Stirring rods
- Magnetic stirrer
- Measuring colve
- pH meter

### Procedure

**For 1x Medium**:

- 3.0 g/l (NH4)2SO4
- 3.2 g/l Na2SO4 x10H2O
- 0.1 g/l KCl
- 0.05 g/l K2HPO4
- 0.5 g/l MgSO4 x7H2O
- 0.01 g/l Ca(NO3)2

**For 10x Stock**:

- 30 g/l (NH4)2SO4
- 32 g/l Na2SO4 x10H2O
- 1 g/l KCl
- 0.5 g/l K2HPO4
- 5 g/l MgSO4 x7H2O
- 0.1 g/l Ca(NO3)2

- Add the constituents into a final volume of 1 liter of water, one at a time, dissolving before adding the next.
- Adjust the pH to 2.0 with sulfuric acid (and/or sodium hydroxide)
-Autoclave

### Timing 

15 minutes + autoclaving time

### Author information 

**Mark Dopson & Stephan Christel**, Systems Biology of Extreme Microorganisms, Dopson, Linnaeus University  

 Correspondence to: Stephan Christel (stephan.christel@lnu.se)

*Source: [Protocol Exchange](http://www.nature.com/protocolexchange/protocols/3809) (2015) doi:10.1038/protex.2015.031. Originally published online 24 March 2015*.