# 517: DESULFOSUDIS MEDIUM


## Main sol. 517

952	ml	**Solution A**	
30	ml	**Solution B**	
11	ml	**Solution C**	
1	ml	**Solution D**	
1	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 45 min), then distributed under same gas atmosphere into anoxic Hungate-type tubes or serum vials and autoclaved. Solution B is autoclaved separately under 80% N2 and 20% CO2 gas atmosphere. Solutions C and F are autoclaved under 100% N2 gas. Solutions D and E are 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. Adjust pH of complete medium to 7.1 - 7.4, if necessary.
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 of some strains at the beginning. For transfers use 5 - 10% inoculum.


## Solution A

0.2	g	KH2PO4	
0.25	g	NH4Cl	
4	g	Na2SO4	
20	g	NaCl	
3.4	g	MgCl2 x 6 H2O	
0.25	g	CaCl2 x 2 H2O	
1	ml	**Trace element solution SL-10**	
1	ml	**Selenite-tungstate solution**	
0.5	ml	Sodium resazurin (0.1% w/v)	
950	ml	Distilled water	


## Solution B

1.5	g	Na2CO3	
30	ml	Distilled water	


## Solution C

0.36	g	Stearic acid	
0.63	ml	NaOH (2 N)	
10	ml	Distilled water	

1. Heat the suspension in a closed bottle (with 100% N2 gas atmosphere in head space) in a boiling water bath. Shake until stearate has dissolved, then autoclave. Stored stearate solution has to be remelted before use.


## Solution D

1	ml	**Wolin's vitamin solution (10x)**	


## Solution E

1	ml	Vitamin B12 (50 µg/ml)	


## Solution F

0.4	g	Na2S x 9 H2O	
10	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.


## Selenite-tungstate solution

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


## Wolin's vitamin solution (10x)

20	mg	Biotin	
20	mg	Folic acid	
100	mg	Pyridoxine hydrochloride	
50	mg	Thiamine HCl	
50	mg	Riboflavin	
50	mg	Nicotinic acid	
50	mg	Calcium D-(+)-pantothenate	
1	mg	Vitamin B12	
50	mg	p-Aminobenzoic acid	
50	mg	(DL)-alpha-Lipoic acid	
1000	ml	Distilled water