Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982. An enzymic assay for the detection and quantitation of component B based on cell-free extract of Methanobacterium thermoautotrophicum stripped of small molecular weight cofactors by anaerobic column chromatography was developed. Component B was purified to homogeneity from boiled cell extract of M. thermoautotrophicum by anaerobic chromatography on Sephadex DEAE-A25, Sephadex G10, and Sephadex G25-F columns. Component B was determined to have a molecular weight of 1,044 by fast atom bombardment mass spectrometry, and a molecular formula of C(,32)H(,47)N(,3)O(,26)P(,2)Na(,4) was proposed for the sodium salt of the compound. A primary amine was present in component B, but no amino acid was detected. Component B was determined to have a monoester phosphate and a diester phosphate, and one mol of aldopentose per mol of component B. The UV absorbance spectrum revealed the presence of two absorbance peaks in component B: one at 267 nm and the other at 233 nm. It was concluded that component B contained a nucleotide moiety. The function of component B was not determined. Cyanocobalamin was found to greatly stimulate methylreductase activity in the component B assay system, but the cause of the stimulation was not determined. A defined medium was developed for Methanomicrobium mobile; this made possible the study of mobile factor, which is required for the growth of M. mobile. M. mobile was found to require acetate, isobutyrate, 2-methylbutyrate, isovalerate, tryptophan, para-aminobenzoic acid, pyridoxine, thiamine, biotin, and vitamin B(,12) for its growth. Sources of the branched-chain amino acids would not substitute for the branched-chain volatile fatty acids. Indole would substitute for tryptophan, but skatole, anthranilic acid, shikimic acid, or 3-indolelactic acid could not substitute. Folic acid could not substitute for para-aminobenzoic acid. Mobile factor was partially purified by anaerobic chromatography on a Sephadex DEAE-A25 column and a Dowex 50W-X4 column. U of I Only Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs