Abstract
The microbial population from a reactor using methane as electron donor for denitrification under microaerophilic conditions was analyzed. High numbers of aerobic methanotrophic bacteria (3 107 cells/ml) and high numbers of acetate-utilizing denitrifying bacteria (2 107 cells/ml) were detected, but only very low numbers of methanol-degrading denitrifying bacteria (4 104 cells/ml) were counted. Two abundant acetate-degrading denitrifiers were isolated which, based on 16S rRNA analysis, were closely related to Mesorhizobium plurifarium (98.4% sequence similarity) and a Stenotrophomonas sp. (99.1% sequence similarity). A methanol-degrading denitrifying bacterium isolated from the bioreactor morphologically resembled Hyphomicrobium sp. and was moderately related to H. vulgare (93.5% sequence similarity). The initial characterization of the most abundant methanotrophic bacterium indicated that it belongs to class II of the methanotrophs. “In vivo”13C-NMR with concentrated cell suspensions showed that this methanotroph produced acetate under oxygen limitation. The microbial composition of reactor material together with the NMR experiments suggest that in the reactor methanotrophs excrete acetate, which serves as the direct electron donor for denitrification.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 19 October 1999 / Received revision: 11 January 2000 / Accepted: 14 January 2000
Rights and permissions
About this article
Cite this article
Costa, C., Dijkema, C., Friedrich, M. et al. Denitrification with methane as electron donor in oxygen-limited bioreactors. Appl Microbiol Biotechnol 53, 754–762 (2000). https://doi.org/10.1007/s002530000337
Issue Date:
DOI: https://doi.org/10.1007/s002530000337