Denitrifying Anaerobic Methane Oxidation (DAMO): Investigation of occurrence and enrichment of DAMO microorganisms
Denitrifying anaerobic methane oxidation (DAMO) is a recently discovered process which is carried out by a bacterium from the NC10 phylum (Candidatus Methylomirabilis oxyfera) and a methanotrophic archaeal group (ANME) (Candidatus Methanoperedens nitroreducens). DAMO microorganisms use methane as electron donor and nitrite or nitrate as electron acceptor, acting as a methane sink by converting methane to carbon dioxide, another GHG with significantly less warming potential. DAMO process has gained global attention since it is considered as a link between the global nutrient cycles of carbon and nitrogen and it has a significant potential to be utilized in sustainable and energy efficient nitrogen removal and reduction of GHG emissions (CH4, N2O) from WWTPs.
DAMO process has been investigated and successfully applied at laboratory scale. However, pure culture enrichment and large-scale application of the DAMO process is limited due to (1) slow growth metabolism (doubling time 1–2 weeks) of the responsible microorganisms which causes a long enrichment period, makes the recovery of DAMO from inhibitory effects more difficult, and (2) possible inhibition factors present in the composite nature of the wastewaters which have potential to be treated with this process. DAMO microorganisms were found and successfully enriched in river and lake sediments, oligotrophic freshwater lakes, municipal and industrial wastewater treatment plant sludge samples and agricultural fields. Yet, there is limited number of studies regarding the effect of inoculum source and optimum source of inoculum. Moreover, until now, the literature lacks detailed studies regarding the impact of commonly occurring compounds encountered in wastewater on DAMO microorganisms.
In this study, the occurrence of DAMO microorganisms in different environments was investigated to observe the activity of microorganisms and to decide the optimum inoculum source potential to shorten the time of enrichment. DAMO culture enrichment was carried out in a sequencing batch reactor (SBR) using the mixture consisting of potential inoculum sources. The effect of conductive materials (GAC/PAC) on DAMO culture will be investigated with the aim of increasing the direct interspecies electron transfer to overcome the slow growth of DAMO culture. The inhibitory impacts of organic matter (COD), phosphate, hydrogen sulfide and ammonia will also be examined in batch reactors.
By: Dilan Laçin
Date & Time: November 20th, 2019 at 15:40 in CZ-14