485. PELOMICROBIUM MEDIUM (PELM)

NH₄Cl 0.33 g

KCl 0.33 g

CaCl₂∙x 6 H₂O 0.03 g

KH₂PO₄ 0.16 g

MgCl₂∙x 6 H₂O 0.33 g

NaCl 10.0 g

NaHCO₃ 2.0 g

Trace element solution (see below) 1 ml

Vitamin solution (see below) 1 ml

Distilled water 1000 ml

Trace element solution:

(NH₄)₂Fe(SO₄)₂ x 6 H₂O (Mohr's salt) 784.0 mg

HCl (concentrated) 5.0 ml

CoCl₂ x H₂O 238.0 mg

(NH₄)₂Ni(SO₄)₂ x 6 H₂O 395.0 mg

Na₂MoO₄ x 2 H₂O 24.0 mg

Na₂WO₄ x 2 H₂O 33.0 mg

ZnSO₄ x 7 H₂O 144.0 mg

CuCl₂ x 2 H₂O 2.0 mg

Na₂SeO₄ 94.0 mg

H₃BO₃ 6.0 mg

MnCl₂ x 4 H₂O 99.0 mg

Distilled water 995.0 ml

Mohr's salt is dissolved firstly in concentrated HCl, and mixed with distilled water and other salts are dissolved in the sequence indicated.

Vitamin solution:

Biotin 20.0 mg

Folic acid 20.0 mg

Pyridoxine 0.1 mg

Riboflavin 50.0 mg

Pantotenoic acid 50.0 mg

p-Aminobenzoic acid 50.0 mg

Thiamine-HCl 50.0 mg

Nicotinic acid 50.0 mg

Vitamin B₁₂ 1.0 mg

Lipoic acid 50.0 mg

Distilled water 1000.0 ml

The medium was prepared by boiling and cooling it under N₂ flow. No reducing agents were added. The isolation medium had a pH of 7.5–8.0 (measured at 25°C). The medium was dispensed in 10 ml portions into 17 ml Hungate’s tubes and heat-sterilized at 121 °C for 30 min; the headspace was filled with H₂/N₂ (80:20, v/v). Potassium nitrate from a sterile anoxic stock solution was added as an electron acceptor to a final concentration of 10 mM before inoculation.

Updated: 08.01.2024