Biodegradation of an explosive compound, glyceryl trinitrate (GTN), was studied with a denitrifying microbial culture grown in a sequencing batch reactor and a GTN acclimated denitrifying culture. The GTN acclimated culture, which were fed on GTN for 1 month, degraded GTN regioselectively via denitration on C1 position as compared to C2 position denitration by denitrifying culture that has never been exposed to GTN. Accumulation of two isomeric glyceryl dinitrates (GDNs) in both culture medium suggests that GDN denitration is the rate-limiting step in GTN biodegradation. The first order GTN degradation rate normalized to cell concentration of the acclimated culture was calculated to be 0.045 (±0.002) L/g-hr. Increasing concentration of electron acceptor(nitrate) resulted in discouraged GTN degradation. According to microbial community analysis, prolonged GTN exposure resulted in 25% increase in the genus level of the GTN acclimated culture with the disappearance of two dominating denitrifying microbial species of Methyloversatilis universalis and Hyphomicrobium zavarzinii in the denitrifying culture. 

Keywords: Denitration, Denitrification, GTN, Microbial shift, Reaction rate, SBR