Effects of Copper and PQQ on the Denitrification Activities of Microorganisms Facilitating Nitrite- and Nitrate-Dependent DAMO Reaction

The growth rate of microorganisms that facilitate the denitrifying anaerobic methane oxidation (DAMO) reaction is slow; thus, establishment of appropriate cultivation conditions for these microorganisms is necessary. In this study, the effect of copper (Cu) and pyrroloquinoline quinone (PQQ) concentrations on the nitrite- and nitrate-dependent DAMO activities of these microorganisms were evaluated using an upflow-type continuous cultivation system. The study confirmed that 6 µM Cu and 2 nM PQQ had a positive effect on nitrite-dependent DAMO, but had little effect on nitrate-dependent DAMO. Conventional basal medium does not contain PQQ; therefore, supplementation of basal medium with PQQ could be an effective method for the cultivation of bacteria that facilitate nitrite-dependent DAMO.