Using RNA-Stable isotope probing to investigate methane oxidation metabolites and active microbial communities in methane oxidation coupled to denitrification.

The active denitrifying communities performing methane oxidation coupled to denitrification (MOD) were investigated using samples from an aerobic reactor (∼20% O and 2% CH) and a microaerobic reactor (2% O, 2% CH) undertaking denitrification. The methane oxidation metabolites excreted in the reactors were acetate, methanol, formate and acetaldehyde. Using anaerobic batch experiments supplemented with exogenously supplied C-labelled metabolites, the active denitrifying bacteria were identified using 16S rRNA amplicon sequencing and RNA-stable isotope probing (RNA-SIP).

Microaerobic methane-driven denitrification in a biotrickle bed - Investigating the active microbial biofilm community composition using RNA-stable isotope probing.

A microaerobic (2% O v/v) biotrickle bed reactor supplied continuously with 2% methane to drive nitrate removal (MAME-D) was investigated using 16S rDNA and rRNA amplicon sequencing in combination with RNA-stable isotope probing (RNA-SIP) to identify the active microorganisms. Methane removal rates varied from 500 to 1000 mmol mh and nitrate removal rates from 25 to 58 mmol mh over 55 days of operation. Biofilm samples from the column were incubated in serum bottles supplemented with CH.

RNA stable isotope probing and high-throughput sequencing to identify active microbial community members in a methane-driven denitrifying biofilm.

Aims: Aerobic methane oxidation coupled to denitrification (AME-D) is a promising process for removing nitrate from groundwater and yet its microbial mechanism and ecological implications are not fully understood. This study used RNA stable isotope probing (RNA-SIP) and high-throughput sequencing to identify the micro-organisms that are actively involved in aerobic methane oxidation within a denitrifying biofilm.

Methods And Results: Two RNA-SIP experiments were conducted to investigate labelling of RNA and methane monooxygenase (pmoA) transcripts when exposed to C-labelled methane over a 96-hour time period and to determine active bacteria involved in methane oxidation in a denitrifying biofilm.

Effect of metabolic uncouplers on the performance of toluene-degrading biotrickling filter.

The biomass control potential of three metabolic uncouplers (carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), carbonyl cyanide m-chlorophenylhydrazone (CCCP), and m-chlorophenol (m-CP)) was tested in biotrickling filters (BTFs) degrading toluene. The experiments employed two types of reactors: a traditional column design and a novel differential BTF (DBTF) reactor developed by De Vela and Gostomski (J Environ Eng 147:04020159, 2021). Uncouplers caused the toluene elimination capacity (EC) (~33 g/mh for column reactors and ~600 g/mh for DBTF) to decrease by 15-97% in a dose-dependent fashion.

New Perspectives on Iron Uptake in Eukaryotes.

All eukaryotic organisms require iron to function. Malfunctions within iron homeostasis have a range of physiological consequences, and can lead to the development of pathological conditions that can result in an excess of non-transferrin bound iron (NTBI). Despite extensive understanding of iron homeostasis, the links between the "macroscopic" transport of iron across biological barriers (cellular membranes) and the chemistry of redox changes that drive these processes still needs elucidating.