DSMZ 421 . CHROMATIUM SALEXIGENS MEDIUM

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Final pH: n.d.

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ml
Compound Amount Unit
Medium 28 1000.00 ml
NaCl 10.00 %
MgCl2 x 6 H2O 0.30 %
Na acetate 0.05 %
Sodium Thiosulfate 0.05 %
1 Supplement medium 28 with NaCl (10%), MgCl2 x 6 H2O (0.3%) Na-acetate (0.05%) and sodium thiosulfate (0.05%). Incubate at 500 to 1000 Lux light intensity.

Main sol. 28 #

1000
Compound Amount Unit
Solution A 460 ml
1 Aliquot Solution A into 100 mL screw-cap bottles, filled with 46 mL each. Bubble with N2/CO2 and autoclave at 121°C for 15 min (as decribed below).
2 Prepare the following solutions (resazurin, bicarbonate and Pfennig's heterotrophic salts) and sterilize as given below.
Resazurin solution 450 ml
Bicarbonate solution 50 ml
Pfennig's heterotrophic salts solution 26 ml
3 Add bicarbonate solution and Pfennig's heterotrophic salts to the resazurin (complete volumina, i.e. 50 mL bicarbonate solution and 26 mL Pfennig's heterotrophic salts solution). Bubble with CO2 in an ice bath under sterile conditions.
4 Fill 50 ml of this mixture to each bottle of solution A (46 mL + 50 mL).
5 Before use, add 4 ml sulfide solution (1.5%) and 0.1 ml Vitamin B12 solution to each 100 mL bottle.
Sulfide solution, 1.5% 40 ml
Vitamin B12 solution 1 ml
6 Adjust the pH with filter-sterilised 1M Na2CO3 to 7.1-7.3.
7 If needed, aliquot into sterile, N2 gassed screw-cap tubes under N2 gas.
8 During the first 24 h, the iron of the medium precipitates in the form of black flocks. No other sediment should arise in the otherwise clear medium.
9 Feed the actively growing culture periodically with neutralized 3% solution of sodium sulfide (use 1 -3 mL/100 mL depending on strain and cultivation stage) to replenish sulfide and with other supplement solutions (see Ref. 3365).
Neutralized sulfide solution 3% (w/v) 10 ml

Neutralized sulfide solution 3% (w/v) #

100
Compound Amount Unit
Na2S x 9 H2O 3 g
Distilled water 100 ml
1 The sulfide solution is prepared in a 250 ml screw-capped bottle with a butyl rubber septum and a magnetic stirrer. The solution is bubbled with nitrogen gas, closed and autoclaved for 15 min. at 121°C. After cooling to room temperature the pH is adjusted to about 7.0 by adding of sterile 2 M H2SO4 drop-wise with a syringe without opening the bottle.