title: Quantitative detection of syntrophic fatty acid-degrading bacterial communities in methanogenic environments.
abstract: In methanogenic habitats, volatile fatty acids (VFA), such as propionate and butyrate, are major intermediates in organic matter degradation. VFA are further metabolized to H(2), acetate and CO(2) by syntrophic fatty acid-degrading bacteria (SFAB) in association with methanogenic archaea. Despite their indispensable role in VFA degradation, little is known about SFAB abundance and their environmental distribution. To facilitate ecological studies, we developed four novel genus-specific quantitative PCR (qPCR) assays, with primer sets targeting known SFAB: Syntrophobacter, Smithella, Pelotomaculum and Syntrophomonas. Primer set specificity was confirmed using in silico and experimental (target controls, clone libraries and melt-curve analysis) approaches. These qPCR assays were applied to quantify SFAB in a variety of mesophilic methanogenic habitats, including a laboratory propionate enrichment culture, pilot- and full-scale anaerobic reactors, cow rumen, horse faeces, an experimental rice paddy soil, a bog stream and swamp sediments. The highest SFAB 16S rRNA gene copy numbers were found in the propionate enrichment culture and anaerobic reactors, followed by the bog stream and swamp sediment samples. In addition, it was observed that SFAB and methanogen abundance varied with reactor configuration and substrate identity. To our knowledge, this research represents the first comprehensive study to quantify SFAB in methanogenic habitats using qPCR-based methods. These molecular tools will help investigators better understand syntrophic microbial communities in engineered and natural environments.
authors: 1Department of Biological Sciences, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA.
authors: Prince P
authors: PP
authors: Mathai
authors: 2Department of Civil, Construction and Environmental Engineering, Water Quality Center, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA.
authors: Daniel H
authors: DH
authors: Zitomer
authors: 1Department of Biological Sciences, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA.
authors: James S
authors: JS
authors: Maki
mesh_terms: D000085:Acetates / Q000378:metabolism; D000332:Aerobiosis; D000693:Anaerobiosis; D000818:Animals; D058491:Bacterial Load; D019149:Bioreactors / Q000382:microbiology; D058448:Biota; D001711:Biotransformation; D002245:Carbon Dioxide / Q000378:metabolism; D002417:Cattle; D019641:DNA, Archaeal / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D004783:Environmental Microbiology; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D006736:Horses; D006859:Hydrogen / Q000378:metabolism; D008969:Molecular Sequence Data; D012275:Oryza; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012417:Rumen / Q000382:microbiology; D017422:Sequence Analysis, DNA
chemical_list: D000085:Acetates; D019641:DNA, Archaeal; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005232:Fatty Acids, Volatile; D012336:RNA, Ribosomal, 16S; D002245:Carbon Dioxide; D006859:Hydrogen