Degradation of p-fluoronitrobenzene in biological and bioelectrochemical systems: Differences in kinetics, pathways, and microbial community evolutions

Biodegradation of p-fluoronitrobenzene (p-FNB) regardless of effective p-FNB removal in a bioelectrochemical system (BES) was achieved for the first time in a biological system (BS). p-FNB degradation showed different kinetics, pathways, and microbial community evolutions in the two systems. About 36 d were required before 100% p-FNB removal in the BSp-FNB, while only 18 d were required in the BESp-FNB. Moreover, the reaction rate constant for p-FNB removal in the BESp-FNB was 1.625 times that in the BSp-FNB. The reduction of nitro groups was the key step for p-FNB removal in the BESp-FNB. However, defluorination was the first step for direct biodegradation of p-FNB in the BSp-FNB. Microbial community analysis showed that the dominant bacteria in the BESp-FNB (20.8% Anaerolineae, 15.9% Flavobacteriia, and 14.8% α-proteobacteria) differed greatly from those in the BSp-FNB (32.8% Flavobacteriia, 24.1% Clostridia and 19.2% Ignavibacteria). In the BSp-FNB, some aerobic microorganisms responsible for direct p-FNB biodegradation were enriched, while p-FA-degrading microorganisms were dominant in the BESp-FNB.