Identification of Methanoculleus spp. as active methanogens during anoxic incubations of swine manure storage tank samples.

摘要: Methane emissions represent a major environmental concern associated with manure management in the livestock industry. A more thorough understanding of how microbial communities function storage tanks is prerequisite for mitigating methane emissions. Identifying microorganisms that are metabolically active an important first step. Methanogenic archaea contributors to methanogenesis stored swine manure, and we investigated methanogenic populations by DNA stable isotope probing (DNA-SIP). Following preincubation samples under anoxic conditions induce substrate starvation, [U-¹³C] acetate was added as labeled substrate. Fingerprint analysis density-fractionated DNA, using length-heterogeneity PCR-amplified mcrA genes (encoding alpha subunit methyl coenzyme M reductase), showed incorporation ¹³C into detectable at situ concentrations (~7g/liter). Fingerprints retrieved from heavy fractions treatment were primarily enriched 483-bp amplicon and, lesser extent, 481-bp amplicon. Analyses based on clone libraries 16S rRNA revealed both these amplicons corresponded Methanoculleus spp. Our results demonstrate uncultivated related acetate-C assimilation during incubation tank samples. Carbon dissimilation rate estimations suggested also hydrogenotrophic pathway predominated methanogenesis.