# 193b: DESULFOFABA MEDIUM


## Main sol. 193b

932	ml	**Solution A**	
30	ml	**Solution B**	
10	ml	**Solution C**	
1	ml	**Solution D**	
20	ml	**Solution E**	
10	ml	**Solution F**	

1. Solution A is sparged with 80% N2 and 20% CO2 gas mixture to reach a pH below 6 (at least 30 min), then distributed under the same gas atmosphere in anoxic Hungate-type tubes or serum vials and autoclaved. Solution B is autoclaved separately under 80% N2 and 20% CO2 gas atmosphere. Solutions C, E and F are autoclaved under 100% N2 gas. 
Solution D is prepared under 100% N2 gas atmosphere and sterilized by filtration. To complete the medium appropriate amounts of solutions B to F are added to the sterile solution A in the sequence as indicated. Final pH of the medium should be 7.1 - 7.4.
2. Note: Addition of 10 - 20 mg sodium dithionite per liter (e.g. from 5% (w/v) solution, freshly prepared under N2 and filter-sterilized) may stimulate growth at the beginning. For transfers use 5 - 10% (v/v) inoculum.


## Solution A

3	g	Na2SO4	
0.2	g	KH2PO4	
0.3	g	NH4Cl	
7	g	NaCl	
0.5	g	KCl	
0.6	g	MgCl2 x 6 H2O	
1	ml	**Selenite-tungstate solution**	
1	ml	**Trace element solution SL-10**	
0.5	ml	Sodium resazurin (0.1% w/v)	
930	ml	Distilled water	


## Solution B

1.5	g	Na2CO3	
30	ml	Distilled water	


## Solution C

1.5	g	Na-propionate	
10	ml	Distilled water	


## Solution D

1	ml	**Seven vitamins solution**	


## Solution E

1.5	g	CaCl2 x 2 H2O	
11.5	g	MgCl2 x 6 H2O	
20	ml	Distilled water	


## Solution F

0.4	g	Na2S x 9 H2O	
10	ml	Distilled water	


## Selenite-tungstate solution

0.5	g	NaOH	
3	mg	Na2SeO3 x 5 H2O	
4	mg	Na2WO4 x 2 H2O	
1000	ml	Distilled water	


## Trace element solution SL-10

10	ml	HCl (25%)	
1.5	g	FeCl2 x 4 H2O	
70	mg	ZnCl2	
100	mg	MnCl2 x 4 H2O	
6	mg	H3BO3	
190	mg	CoCl2 x 6 H2O	
2	mg	CuCl2 x 2 H2O	
24	mg	NiCl2 x 6 H2O	
36	mg	Na2MoO4 x 2 H2O	
990	ml	Distilled water	

1. First dissolve FeCl2 in the HCl, then dilute in water, add and dissolve the other salts. Finally make up to 1000.00 ml.


## Seven vitamins solution

100	mg	Vitamin B12	
80	mg	p-Aminobenzoic acid	
20	mg	D-(+)-biotin	
200	mg	Nicotinic acid	
100	mg	Calcium pantothenate	
300	mg	Pyridoxine hydrochloride	
200	mg	Thiamine-HCl x 2 H2O	
1000	ml	Distilled water