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.