Herein, a novel enro oxacin-degrading fungus was isolated from a rhizosphere sediment of the submerged macrophyte Vallisneria spiralis L.. The isolate, designated KC0924g, was identi ed as a member of the genus Humicola based on morphological characteristics and tandem conserved sequences analysis. The optimal temperature and pH for enro oxacin degradation by strain KC0924g was 28°C and 9.0, respectively. Under such condition, 98.2% of enro oxacin with initial concentration being 1 mg L -1 was degraded after 72 h of incubation, with nine possible degradation products identi ed. Accordingly, four different metabolic pathways were proposed, which were initiated by cleavage of the piperazine moiety, hydroxylation of the aromatic ring, oxidative decarboxylation, or de uorination. In addition to enro oxacin, strain KC0924g also degraded other uoroquinolone antibiotics (cipro oxacin, nor oxacin, and o oxacin), malachite green (an illegal addition in aquaculture) and leucomalachite green. Pretreatment of cells of strain KC0924g with Cu 2+ accelerated ENR degradation. Moreover, it was speculated that one avin-dependent monooxygenase and/or one laccase involved in ENR degradation based on the increased transcriptional levels of these two genes after Cu 2+ induction. This work enriches strain resources for enro oxacin remediation and, more importantly, would facilitate studies on the molecular mechanism of ENR degradation with degradation-related transcriptome available.