A novel identified Pseudomonas aeruginosa, which exhibited nitrate‐ and nitrite‐dependent methane oxidation abilities, could alleviate the disadvantages caused by nitrate supplementation in rumen fluid fermentation

Abstract

After the occurrence of nitrate-dependent anaerobic methane oxidation (AMO) in rumen fluid culture was proved, the organisms that perform the denitrifying anaerobic methane oxidizing (DAMO) process in the rumen of dairy goat were investigated by establishing two enrichment culture systems, which were supplied with methane as the sole carbon source and NaNO 3 or NaNO 2 as the electron acceptor. Several Operational Taxonomic Units (OTU) belonging to Proteobacteria became dominant in the two enrichment systems. The identified Pseudomonas aeruginosa, which was isolated from the NaNO 2 enrichment system, could individually perform a whole denitrifying anaerobic methane oxidizing process. Further in vitro rumen fermentation showed that supplementation with the isolated P. aeruginosa could reduce methane emissions, alleviate the nitrite accumulation and prevent the decrease in propionic acid product caused by nitrate supplementation.

Significance of anaerobic oxidation of methane (AOM) in mitigating methane emission from major natural and anthropogenic sources: a review of AOM rates in recent publications

“…The publications on nitrite/nitrate-DAMO raised the interest in engineering this AOM pathway for denitrication, which is currently a main nutrient removal step in the biological wastewater treatment process. 47,48,221 Besides, DAMO may also be applied for methane emission reduction from ruminant livestock, 222 which accounts for almost one-third of total anthropogenic methane emissions. pathways for denitrication.…”

“…The publications on nitrite/nitrate-DAMO raised the interest in engineering this AOM pathway for denitrification, which is currently a main nutrient removal step in the biological wastewater treatment process. 47,48,221 Besides, DAMO may also be applied for methane emission reduction from ruminant livestock, 222 which accounts for almost one-third of total anthropogenic methane emissions. 1 DAMO (nitrogen mainly as NO 2 − /NO 3 − ) and DAMO coupled with anaerobic ammonium oxidation (DAMO-Anammox, NO 2 − /NO 3 − together with a significant concentration of NH 4 + ) are two of the commonly studied AOM pathways for denitrification.…”