title: Microbial trophic interactions and mcrA gene expression in monitoring of anaerobic digesters.
abstract: Anaerobic digestion (AD) is a biological process where different trophic groups of microorganisms break down biodegradable organic materials in the absence of oxygen. A wide range of AD technologies is being used to convert livestock manure, municipal and industrial wastewaters, and solid organic wastes into biogas. AD gains importance not only because of its relevance in waste treatment but also because of the recovery of carbon in the form of methane, which is a renewable energy and is used to generate electricity and heat. Despite the advances on the engineering and design of new bioreactors for AD, the microbiology component always poses challenges. Microbiology of AD processes is complicated as the efficiency of the process depends on the interactions of various trophic groups involved. Due to the complex interdependence of microbial activities for the functionality of the anaerobic bioreactors, the genetic expression of mcrA, which encodes a key enzyme in methane formation, is proposed as a parameter to monitor the process performance in real time. This review evaluates the current knowledge on microbial groups, their interactions, and their relationship to the performance of anaerobic biodigesters with a focus on using mcrA gene expression as a tool to monitor the process.
authors.affiliation: Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, Torreón México ; Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg Germany.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Alvarado
authors.affiliation: Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, Torreón México.
authors.forename: Lilia E
authors.initials: LE
authors.lastname: Montañez-Hernández
authors.affiliation: Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, Torreón México.
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Palacio-Molina
authors.affiliation: Instituto de Biotecnología - Universidad Nacional Autónoma de México, Cuernavaca México.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Oropeza-Navarro
authors.affiliation: Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, Torreón México.
authors.forename: Miriam P
authors.initials: MP
authors.lastname: Luévanos-Escareño
authors.affiliation: Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, Torreón México.
authors.forename: Nagamani
authors.initials: N
authors.lastname: Balagurusamy
keywords: anaerobic digestion; mcrA gene expression; methanogens; microbial interactions; monitoring biodigesters