Cook 5-10 min (colour turns first red and then yellow). Cool on ice. Add
biotin 10.0 mg, p-aminobenzoic acid 10.0 mg and L-cysteinium chloride
(monohydr.) 0.5 g. Adjust pH to 7.0. Heat slightly to dissolve (do not
boil). Distribute into tubes á 5 ml. After autoclaving (at 121°C for 15
min) add 5 ml sterile sugar solution (10 g/l xylose to TYX and glucose to
TYG).
