NH4Cl 0.10 g KH2PO4 3.00 g MgCl2 x 6 H2O 0.10 g CaCl2 x 2 H2O 0.14 g Sulfur, powdered 10.00 g Distilled water 1000.00 ml Dissolve all ingredients, except the sulfur, in distilled water and adjust the pH to 4.2, then autoclave. Place the sulfur in screw-capped tubes or bottles and sterilize by autoclaving at 112°C for 15 min. Before use, aseptically layer the sulfur onto the surface of autoclaved liquid basal medium. For DSM 612 add 0.01% yeast extract (sterilized separately).