Spatiotemporal dynamics and correlation networks of bacterial and fungal communities in a membrane bioreactor.
To systematically study biofilm communities responsible for biofouling in membrane bioreactors (MBRs), we characterized the spatiotemporal dynamics of bacterial and fungal biofilm communities, and their networks, in a pilot-scale flat-sheet MBR treating actual municipal wastewater. Activated sludge (AS) and membrane samples were collected on days 4 and 8. The membranes were cut into 18 tiles, and bacterial and fungal communities were analyzed using next generation sequencing. Nonmetric multidimensional scaling (NMDS) plots revealed significant temporal variations in bacterial and fungal biofilm communities due to changes in the abundances of a few dominant members. Although the experimental conditions and inoculum species pools remained constant, variogram plots of bacterial and fungal communities revealed decay in local community similarity with geographic distance at each sampling time. Variogram modeling (exponential rise to maximum, R2≥ 0.79) revealed that decay patterns of both communities were different between days 4 and 8. In addition, networks of bacteria or fungi alone were distinct in network composition between days 4 and 8. The day-8 networks were more compact and clustered than those of the earlier time point. Bacteria-fungi networks show that the number of inter-domain associations decreased from 113 to 40 with time, confirming that membrane biofilm is a complex consortium of bacteria and fungi. Spatiotemporal succession in biofilm communities may be common on MBR membranes, resulting from different geographic distributions of initial microbial populations and their priority effects.
Department of Microbiology, Pusan National University, Pusan 46241, South Korea.
So-Yeon
SY
Jeong
National Institute of Ecology, Choongnam 33657, South Korea.
Taewoo
T
Yi
School of Chemical and Biological Engineering, Seoul National University, Seoul 08826, South Korea.
Chung-Hak
CH
Lee
Department of Microbiology, Pusan National University, Pusan 46241, South Korea. Electronic address: tkim@pusan.ac.kr.
Tae Gwan
TG
Kim
D001419:Bacteria / Q000235:genetics; D057219:Biofouling; D019149:Bioreactors / Q000382:microbiology; D059014:High-Throughput Nucleotide Sequencing; D008567:Membranes, Artificial; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid
D008567:Membranes, Artificial; D012722:Sewage
Bacteria; Fungi; Membrane bioreactor; Microbial community; Microbial network