mcrA Gene abundance correlates with hydrogenotrophic methane production rates in full-scale anaerobic waste treatment systems

R. L. Morris, V. P. Tale, P. P. Mathai, D. H. Zitomer, J. S. Maki

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Anaerobic treatment is a sustainable and economical technology for waste stabilization and production of methane as a renewable energy. However, the process is under-utilized due to operational challenges. Organic overload or toxicants can stress the microbial community that performs waste degradation, resulting in system failure. In addition, not all methanogenic microbial communities are equally capable of consistent, maximum biogas production. Opinion varies as to which parameters should be used to monitor the fitness of digester biomass. No standard molecular tools are currently in use to monitor and compare full-scale operations. It was hypothesized that determining the number of gene copies of mcrA, a methanogen-specific gene, would positively correlate with specific methanogenic activity (SMA) rates from biomass samples from six full-scale anaerobic digester systems. Positive correlations were observed between mcrA gene copy numbers and methane production rates against H2 : CO2 and propionate (R2 = 0·67-0·70, P < 0·05) but not acetate (R2 = 0·49, P > 0·05). Results from this study indicate that mcrA gene targeted qPCR can be used as an alternate tool to monitor and compare certain methanogen communities in anaerobic digesters.

Original languageEnglish (US)
Pages (from-to)111-118
Number of pages8
JournalLetters in Applied Microbiology
Issue number2
StatePublished - Feb 1 2016

Bibliographical note

Funding Information:
We thank the owners and operators of the full-scale industrial and municipal anaerobic digesters that were sampled for providing us with biomass and operating information, and Mike Dollhopf of the Water Quality Center, Marquette University, for all his assistance during this investigation. Support for this work was provided by WE Energies and by Marquette University.

Publisher Copyright:
© 2016 The Society for Applied Microbiology.


  • Anaerobic digestion
  • Methanogens
  • Quantitative PCR
  • Specific methane activity rates
  • mcrA gene


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