Effect of trace elements and vitamins on the growth of Methanosarcina barkeri

Abstract Growth of Methanosarcina barkeri on methanol as energy source was found to be dependent on cobalt and molybdenum. In the presence of 10 −6 M Co and 5 × 10 −7 M Mo optimal growth occurred. Furthermore it could be demonstrated that nickel and selenium each in a concentration of 10 −7 M stimulated the growth of this methanogenic bacterium while the following elements tested in the range of 10 −7 M to 10 −3 had no influence: B, Cr, Cu, Mn, Pb. The requirement of Co and Ni for optimal growth are in accordance with the results that the cells contain the Co containing corrinoid Factor III (0.1 – 0.2 mg 5‐hydroxylbenzimidazolylcyanocobamide per g wet cells) and Factor F 430 , a nickel component. Studies on the vitamin dependency of M. barkeri showed that this strain needs only the vitamin riboflavin for the growth in a defined medium. Under these conditions a cell density of 2.6 g dry cells/l could be obtained in a fed batch culture.