Identification of active and taxonomically diverse 1,4-dioxane degraders in a full-scale activated sludge system by high-sensitivity stable isotope probing

Abstract

1,4-Dioxane is one of the most common and persistent artificial pollutants in petrochemical industrial wastewaters and chlorinated solvent groundwater plumes. Despite its possible biological treatment in natural environments, the identity and dynamics of the microorganisms involved are largely unknown. Here, we identified active and diverse 1,4-dioxane-degrading microorganisms from activated sludge by high-sensitivity stable isotope probing of rRNA. By rigorously analyzing 16S rRNA molecules in RNA density fractions of 13C-labeled and unlabeled 1,4-dioxane treatments, we discovered 10 significantly 13C-incorporating microbial species from the complex microbial community. 16S rRNA expression assays revealed that 9 of the 10 species, including the well-known degrader Pseudonocardia dioxanivorans, an ammonia-oxidizing bacterium and phylogenetically novel bacteria, increased their metabolic activities shortly after exposure to 1,4-dioxane. Moreover, high-resolution monitoring showed that, during a single year of operation of the full-scale activated sludge system, the nine identified species exhibited yearly averaged relative abundances of 0.001–1.523%, and yet showed different responses to changes in the 1,4-dioxane removal efficiency. Hence, the co-existence and individually distinct dynamics of various 1,4-dioxane-degrading microorganisms, including hitherto unidentified species, played pivotal roles in the maintenance of the biological system removing the recalcitrant pollutant.

Subgroup level differences of physiological activities in marine Lokiarchaeota

“…of nucleic acids [ 12 ]. Using RNA-SIP facilitates ultra-sensitive labelling with a detection threshold below 0.001% for fully 13 C-labelled nucleic acids [ 13 , 14 ]. Thus, in order to illuminate the in situ metabolic capabilities and activities of uncultivated archaea including Lokiarchaeota in marine sediments, we used both RNA-SIP and DNA-SIP techniques in combination with various 13 C-labelled substrates.…”

1,4‐Dioxane‐contaminated groundwater remediation in the anode chamber of a microbial fuel cell

“…For bacterial phyla, on the anode surface, Bacteroidetes, Firmicutes, and Proteobacteria occupied 53.8%, 32.0%, and 13.9% without methanol and occupied 39.3%, 51.0%, and 9.7% with methanol, respectively (Figure a). Bacteroidetes and classes of Proteobacteria including Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria have been detected for 1,4‐dioxane biodegradation in batch reactors inoculated activated sludge or industrial sludge (Aoyagi et al, ; Shin, Sung, Moon, & Nam, ). Firmicutes were included in other phyla for 1,4‐dioxane biodegradation in a previous study (Guan, Liu, Wang, Li, & Zheng, ).…”

CO2 conversion to methane and biomass in obligate methylotrophic methanogens in marine sediments

“…Combined with downstream analysis including qPCR, 16S rRNA sequencing and cloning, we directly show that members of the genus Methanococcoides were the predominantly active methylotrophic methanogens in SRZ incubations, while Methanococcoides together with Methanolobus were dominant in MZ incubations. In addition, archaea with an abundance less than 0.01% showed a higher proportion in light fractions than in heavy fractions (Table S4), excluding the populations under high-sensitivity SIP conditions [60]. A small peak at 1.808 g mL −1 was detected in RNA-SIP profiles from the SRZ incubations amended with 13 Cmethanol and unlabeled DIC, which originated most likely from methylotrophic methanogens as shown by relative abundances of methanogens in the heavy fractions (Fig.…”