Secondary alcohols as hydrogen donors for CO2-reduction by methanogens

Abstract

SUMMARYOut of 22 methanogens Methanobacterium formicicum, Methanobacterium bryantii M.o.H., Methanogenium marisnigri, Methanomicrobium paynteri, Methanocorpusculum paroum and the new coccoid methanogenic isolates GKZPZ and SZSXXZ were found to grow at the expense of 2-propanol and 2-butanol + CO 2. 2-Propanol was oxidized to acetone and 2-butanol was converted to 2-butanone during CO2-reduction to methane.Growth was poor compared to that on Hz/CO 2, and in the presence of both, 2-propanol and H 2, molecular hydrogen was the preferred reductant. Acetone, formed during oxidation of 2-propanol in the absence of hydrogen, was reduced again to 2-propanol, when the culture was supplied with H2/CO 2. Ethanol, 1-propanol, 1-butanol, 2-pen-tanol and cyclohexanol could not serve as hydrogen donors for methanogenesis.

Methanobacterium oryzae sp. nov., a novel methanogenic rod isolated from a Philippines ricefield.

“…Strains : 1, FPi T ; 2, Methanobacterium formicicum ; 3, Methanobacterium palustre ; 4, Methanobacterium bryantii ; 5, Methanobacterium uliginosum. Data from Bryant et al (1967), Bryant & Boone (1987), Ko$ nig (1984), Zellner & Winter (1987) and Zellner et al (1989 it can be inferred that strain FPi T is distinct from Methanobacterium uliginosum, especially since strain FPi T and Methanobacterium bryantii are phylogenetically distinct, as reported above. This inference is also supported by the phenotypic differences observed between strain FPi T (grows on formate) and Methanobacterium uliginosum (does not grow on formate) (Table 1).…”

Reclassification of Methanogenium tationis and Methanogenium liminatans as Methanofollis tationis gen. nov., comb. nov. and Methanofollis liminatans comb. nov. and description of a new strain of Methanofollis liminatans

“…Analyses. Volatile fatty acids, alcohols, hydrogen and methane were analysed by GC (Zellner &Winter, 1987). The Colour Gram 2 staining set from bioMerieux was used for Gram staining according to the manufacturer's instructions.…”

Methanolacinia gen. nov., incorporating Methanomicrobium paynteri as Methanolacinia paynteri comb. nov.

“…However, this organism utilized, in addition, 2-propanol, 2-butanol (45) and cyclopentanol (2) as hydrogen donors for the reduction of C02 to CH4, with concomitant oxidation of the alcohols to the respective ketones (45).…”

“…The oven temperature was 120°C for methanol and ethanol, 140°C for 2-butanol and 2-butanone, 180°C for 1-propanol, 1-butanol, acetate, 2-pentanol and 2-pentanone, and 195°C for cyclopentanol, cyclohexanol, cyclopentanone and cyclohexanone. Detection was by flame ionization at 220°C (45). Sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE).…”