Assessing Methanogenic Archaeal Community in Full Scale Anaerobic Sludge Digester Systems in Dubai, United Arab Emirates

Abstract

Introduction:Anaerobic digestion for methane production comprises of an exceptionally diverse microbial consortium, a profound understanding about which is still constrained. In this study, the methanogenic archaeal communities in three full-scale anaerobic digesters of a Municipal Wastewater Treatment Plant were analyzed by Fluorescence in situ hybridization and quantitative real-time Polymerase Chain Reaction (qPCR) technique.Methods & Materials:Fluorescence in situ hybridization (FISH) was performed to detect and quantify the methanogenic Archaea in the sludge samples whereas qPCR was carried out to support the FISH analysis. Multiple probes targeting domain archaea, different orders and families of Archaea were used for the studies.Results and Discussion:In general, the aceticlastic organisms (Methanosarcinaceae & Methanosaetaceae) were more abundant than the hydrogenotrophic organisms (Methanobacteriales, Methanomicrobiales, Methanobacteriaceae & Methanococcales). Both FISH and qPCR indicated that family Methanosaetaceae was the most abundant suggesting that aceticlastic methanogenesis is probably the dominant methane production pathway in these digesters.Conclusion:Future work involving high-throughput sequencing methods and correlating archaeal communities with the main operational parameters of anaerobic digesters will help to obtain a better understanding of the dynamics of the methanogenic archaeal community in wastewater treatment plants in United Arab Emirates (UAE) which in turn would lead to improved performance of anaerobic sludge digesters.

Exploring the limits of anaerobic biodegradability of urban wastewater by AnMBR technology

“…The predominance of methanogenic order Methanosarcinales (9%) has been previously observed by other authors 37,38 also using FISH technique in anaerobic digesters. The results obtained in the present study suggest that: (i) the methane in this AnMBR is mainly produced through acetoclastic methanogenesis; (ii) a high SRT favors this group, since the percentage is significantly higher than the one obtained at 70 d (Table 7), while the rest of the detected MA orders remained constant.…”

Effects of combined tannic acid/fluoride on sulfur transformations and methanogenic pathways in swine manure

“…To avoid such inconclusive results, it is necessary to use inocula with a balanced methanogenic community structure, where both methanogenesis pathways are equally active. For that reason wastewater sludge, which is often dominated by acetoclastic methanogens [ 52 , 53 ], and cattle manure was also examined in this study.…”

Illumina sequencing of 16S rRNA genes reveals a unique microbial community in three anaerobic sludge digesters of Dubai

“…Furthermore, the sludge produced during anaerobic digestion is used as a biofertilizer in public parks and local agricultural farms in Dubai. All three digesters had a capacity of 7433 m 3 and operated at a mesophilic temperature ranging between 32–37°C [ 15 ]. The digesters were fed with 60 and 40% of raw and activated sludge, respectively.…”

“…Dubai also has future plans to use biogas produced from these WWTPs. Therefore, we have previously reported the microbial community in these digesters using the fluorescent in situ hybridization and quantitative PCR technique [ 15 ]. Here we report a comprehensive mapping of key microbial operational taxonomic units present in these digesters.…”