Nutritional requirements for growth of Methanothrix concilii

Abstract

Methanothrix concilii, which is a mesophilic, aceticlastic methanogen, required 6.8 mM inorganic nitrogen for maximal growth rate in a mineral salts – vitamins medium containing 73.5 mM acetic acid. Cysteine hydrochloride, sodium sulfide, or glutathione at optimum concentrations of 6.0, 1.0, and 12.0 mM, respectively, served as the sole source of sulphur for growth. Of the 10 vitamins tested, only biotin, thiamine hydrochloride, and p-aminobenzoic acid stimulated growth. The optimum iron and nickel concentrations were 1–5 and 0.1 μM, respectively. Both calcium and magnesium, at an optimum concentration of 250 and 500 μM, respectively, were essential for growth. The optimum concentrations of manganese, cobalt, and zinc, in conjunction with one another, were 2.5, 10.0, and 5.0 μM, respectively.