Unraveling the biophysical underpinnings to the success of multispecies biofilms in porous environments.
Scheidweiler D, Peter H, Pramateftaki P, de Anna P, Battin TJ
ISME J. Mar 2019. doi: 10.1038/s41396-019-0381-4
COMMENT: Previous studies on biofilms in porous environments used monospecies systems. To mimic the diversity typically encountered in stream biofilms, Scheidweiler et al, used a natural inoculum containing hundreds of OTUs. This study investigates the interactions between biofilms and their physical environment in a porous system. Community composition was revealed by sequencing of the 16S rRNA gene.
We developed a fluidic device to study the local hydrodynamics and related mass transfer as potential physical modulators of multispecies biofilm growth across scales, ranging from individual grain–pore complexes to the porous landscape contained within the fluidic device.
We found that hydrodynamics and related mass transfer mediated the differentiation of biofilms into an annular base biofilm (BB) and streamers reproducibly across pore-grain complexes.
The architectural differentiation of biofilms into base biofilm (BB) and streamers was highly reproducible and this independent of the starting inoculum and spatial configuration of the grains within the fluidic devices
Architectural differentiation was not paralleled by a differentiation of community composition.
The architectural differentiation into BB and streamers was not reflected by pronounced differences in community composition as revealed by sequencing of the 16 S rRNA gene.
Taxonomic diversity was relatively high, including 32 bacterial phyla and four archaeal phyla.
Most OTUs belonged to the beta-, gamma-, and alpha-proteobacterial classes, accounting for 90.6% of the sequences in BB and for 84.4% of the sequences in streamers.
Our findings suggest that architectural plasticity enables biofilms to differentiate into BB and streamers to complementarily exploit the space provided by the grain–pore complexes.
Ultimately this increases the carrying capacity of biofilms, which is a cornerstone of the ecological success of any organism.