THE PLASTISPHERE – UNVEILING POLYMER SPECIFIC MICROORGANISMS
There is still no consistency concerning the microbial community compositions on synthetic polymers and other surfaces (e.g. glass) in the marine environment. Moreover, there is a need to identify those microorganisms that are preferentially able to colonize and interact with synthetic polymer surfaces, as opposed to generalists that colonize other surfaces. We hypothesized that i.) polymer specific microorganisms are tightly attached to the polymeric surface and ii.) a general core community is building the upper biofilm layers of all surfaces including plastics. Accordingly we developed a new high-pressure treatment technique to remove the upper biofilm layers and to further isolate polymer specific microorganisms. Five different synthetic polymer films and glass were incubated in situ for 21 months in a seawater flow through system. Those were high-pressure treated and thereafter used as a source for re-colonisation of the same sterile polymer. Re-colonization was proven by fluorescent microscopy. Re-colonized polymers were further incubated in vitro before subjected to enrichments and isolated on HaHa_100 agar. Isolates were dereplicated by MALDI-TOF (matrix assisted laser desorption/ionization time-of-flight). To characterize the re-colonization process isolates were identified by RNA gene sequencing and re-colonized polymers, the untreated biofilm and the polymer surface were visualized via Scanning Electron microscopy. Our findings indicate the presence of polymer specific microorganisms which could be involved in polymer degradation processes.