# 1456: DESULFOSOMA MEDIUM ## Main sol. 1456 0.3 g K2HPO4 0.3 g KH2PO4 1 g NaCl 1 g NH4Cl 0.1 g KCl 0.1 g CaCl2 x 2 H2O 0.5 g MgCl2 x 6 H2O 2.8 g Na2SO4 1 g Yeast extract (OXOID) 1 g Trypticase peptone (BD BBL) 1 ml **Trace element solution SL-10** 0.5 ml Sodium resazurin (0.1% w/v) 1.5 g Na2CO3 2.5 g Na-pyruvate 0.5 g L-Cysteine HCl x H2O 0.5 g Na2S x 9 H2O 1000 ml Distilled water 1. Dissolve ingredients except carbonate, pyruvate, cysteine and sulfide, then sparge medium with 80% N2 and 20% CO2 gas mixture for 30 - 45 min to make it anoxic. Dispense medium under the same gas atmosphere into anoxic Hungate-type tubes or serum vials and autoclave. Add pyruvate (sterilized by filtration), cysteine and sulfide from sterile anoxic stock solutions prepared under 100% N2 gas and carbonate from a sterile anoxic stock solution prepared under 80% N2 and 20% CO2 gas mixture. Prior to use adjust pH of complete medium to 7.0 - 7.2, if necessary. ## 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.