The study of natural biofilm formation and microbial community structure for recirculating aquaculture system

Abstract Biofilter is the core unit of recirculating aquaculture system(RAS), which mainly to achieve in situ purification and restoration water pollutants by enriching microorganisms on biofilters form biofilms. To explore changes metabolic characteristics microbial communities process biofilm formation RAS under low-temperature environment, 16S rRNA high-throughput sequencing was applied analyze differences composition structural initiation group (I) group(B), PICRUSt functional gene prediction method used predict functions. Results diversity showed that OTUs numbers, Shannon index richness increased significantly after bio-film formation(p<0.05). The Pcoa results indicated community B quite different compared with I. After formation, phylum Proteobacteria, Bacteroidota, Fusobacteriota, Patescibacteria Verrucomicrobiota were main dominant bacteria biofilter. denitrifying bacteria, such as Comamonadaceae Rhodobacteraceae B. Meanwhile, activities aspects Carbohydrate Metabolism, Energy Lipid Amino Acid Metabolism Terpenoids Polyketides Enzyme Families obviously enhanced(p <0.05).