H2-CO2-Dependent Anaerobic O-Demethylation Activity in Subsurface Sediments and by an Isolated Bacterium

AUTOR(ES)

Liu, Shi

RESUMO

The ability of microorganisms in sediments from the Atlantic Coastal Plain to biodegrade methoxylated aromatic compounds was examined. O-demethylation activity was detected in deep (121- and 406-m) sediments, as well as in the surface soil. A syringate-demethylating consortium, containing at least three types of bacteria, was enriched from a deep-sediment sample in a medium containing syringate as the sole organic carbon source and with a N2-CO2 atmosphere. An isolate which demethylated syringate was obtained from the enrichment on an agar medium incubated under a H2-CO2 but not a N2-CO2 or N2 atmosphere. O demethylation of syringate of this isolate was dependent on the presence of both H2 and CO2 in the gas phase. The metabolism of syringate occurred in a sequential manner: methylgallate accumulated transiently before it was converted to gallate. Mass balance analysis suggests that the stoichiometry of the reaction in this isolate proceeds in accordance with the following generalized equation: C7H3O3(OCH3)n- + nHCO3- + nH2 → C7H3O3(OH)n- + nCH3COO- + nH2O.

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