Microbial uniqueness of architecture modified loofah sponge as biological filler for efficient nitrogen removal

By shrinking the major central apertures in the natural loofah sponge, it is easy to establish inner-DO-reduced-zones within the biofiller. The study compared the performances of two sequencing batch biofilm reactors (SBBR), which were packed with the natural and the major-central-pores-shrunk (the architecture modified) biofillers, respectively. The modified biofillers inhabited higher abundance of anaerobic bacteria, including Lentimicrobiaceae and Anaerolinea Chloroflexi (the acetogenic bacteria). These bacteria were found to closely related to some types of denitrifying bacteria (Rhodobacteraceae). The relative abundance of narG and nosZ genes in the attached-growth biomass of the architecture modified biofillers were 5% and 10% higher, respectively. The potential nitrogen removal pathways are discussed. This study demonstrated the advances and insight of using the internal closed porous biofiller in Sequencing Batch Biofilm Reactor (SBBR) without deliberately controlling the DO level in the reactor.