biofilm metagenome Raw sequence reads

A denitrification fixed film biofilter using polycaprolactone (PCL) as carbon source and biofilm carrier was developed for removing nitrate-nitrogen (NO3--N) in water from a recirculating aquaculture system in this study. As the hydraulic retention time (HRT) increased from 2 h to 8 h. The highest removal rate of 1.05 ± 0.33 g NO3--N/L• d was reached at an HRT of 8 h with a flow rate of 0.71 L/ h. The unused dissolved organic carbon (DOC) from PCL degradation was less than 10 mg/L for all HRTs and increased with HRT. Observation of the PCL surface indicated that chain scission by hydrolytic degradation and biological utilization in the reactors did not significantly change the chemical structure of the PCL. Microbial community analysis showed that Proteobacteria was predominant in the inoculum, with relative abundances of 62%, respectively. Six genera—Acidovorax, Azospira and Comamonas, Diaphorobacter, Ignavibacterium, and Frateuria—were capable of both degrading PCL and denitrifying NO3--N.