Fast development of microbial cultures for the anaerobic oxidation of CH4 coupled to denitrification employing widely available inocula

Edgardo I. Valenzuela , José A. Contreras , Guillermo Quijano

Biochemical Engineering Journal |

Abstract

This work assessed the potential of two widely available inocula for the implementation of anaerobic oxidation of methane coupled with NO₃^– reduction (N-AOM). Methane consumption via N-AOM was observed within the first 40–67 days of culture using secondary activated sludge (AS) and a mixture of AS and anaerobic granular sludge(AS+AGS) as inoculum. Maximum methane removal rates of 0.13 ± 0.02 and 0.17 ± 0.01 gCH₄ m⁻³ h⁻¹ were recorded for AS and AS+AGS cultures, respectively. 16 S rRNA high throughput sequencing applied to biomass samples throughout incubation revealed the absence of the archaeon Methanoperedens nitroreducens and the bacterium Methylomirabilis oxyfera in AS and AS+AGS cultures. Instead, members from the Bacteroidetes, Chloroflexi, Proteobacteria, and Euryarchaeota lineages were predominant in the cultures. Nitrous oxide, an undesirable intermediate of nitrate reduction, was not detected in measurements performed at the end of the incubations. The methane consumption rates recorded are comparable with N-AOM systems requiring acclimationperiods of up to 600 days. Therefore, this work confirmed that N-AOM processes might be implemented with inocula available in bulk amounts in short periods, which facilitates the application of this process for the treatment of residual methane in wastewater treatment plants and other waste management facilities.

Cite this article

Valenzuela, E. I., Contreras, J. A., & Quijano, G. (2022). Fast development of microbial cultures for the anaerobic oxidation of CH coupled to denitrification employing widely available inocula. Biochemical Engineering Journal, 184, 108492. https://doi.org/10.1016/j.bej.2022.108492