# 195d: KNH MEDIUM


## Main sol. 195d

952	ml	**Solution A**	
30	ml	**Solution B**	
10	ml	**Solution C**	
1	ml	**Solution D**	
13	ml	**Solution E**	

1. Solution A is sparged with 80% H2 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 to 30% of their volume and autoclaved. Solution B is autoclaved separately under 80% N2 and 20% CO2 gas atmosphere. Solution C is autoclaved under 100% N2 gas. Solutions D and E are prepared under 100% N2 gas atmosphere and sterilized by filtration. To complete the medium solutions B to E are added to the sterile solution A in the sequence as indicated. Final pH of the medium should be 7.1 - 7.4.
2. After inoculation add 1 bar overpressure of sterile 80% H2 and 20% CO2 gas mixture.


## Solution A

3	g	Na2SO4	
0.2	g	KH2PO4	
0.3	g	NH4Cl	
21	g	NaCl	
3	g	MgCl2 x 6 H2O	
0.5	g	KCl	
0.15	g	CaCl2 x 2 H2O	
0.5	g	Yeast extract	
0.1	g	Ascorbic acid	
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

0.7	g	Na-acetate	
10	ml	Distilled water	


## Solution D

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


## Solution E

7.2	ml	Tris-HCl buffer (1.0 M solution, pH 8.0)	
4.8	ml	Na3-NTA x H2O (0.5 M solution)	
0.55	ml	TiCl3 (15% w/v solution in HCl; Riedel-de Haen)	

1. Sterilize by filtration.


## 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.


## 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