Microbial colonization of different microplastic types and biotransformation of sorbed PCBs by a marine anaerobic bacterial community

Antonella Rosato; Monica Barone; Andrea Negroni; Patrizia Brigidi; Fabio Fava; Ping Xu; Marco Candela; Giulio Zanaroli

doi:10.1016/j.scitotenv.2019.135790

Microbial colonization of different microplastic types and biotransformation of sorbed PCBs by a marine anaerobic bacterial community

Sci Total Environ. 2020 Feb 25:705:135790. doi: 10.1016/j.scitotenv.2019.135790. Epub 2019 Nov 26.

Authors

Antonella Rosato¹, Monica Barone², Andrea Negroni¹, Patrizia Brigidi², Fabio Fava¹, Ping Xu³, Marco Candela², Giulio Zanaroli⁴

Affiliations

¹ Dept. of Civil, Chemical, Environmental and Materials Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy.
² Dept. of Pharmacy and Biotechnology (FaBit), Alma Mater Studiorum University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy.
³ School of Life Science & Biotechnology, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, People's Republic of China.
⁴ Dept. of Civil, Chemical, Environmental and Materials Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy. Electronic address: giulio.zanaroli@unibo.it.

PMID: 31972939
DOI: 10.1016/j.scitotenv.2019.135790

Abstract

We investigated the colonization dynamics of different microplastic (MP) pellets, namely, polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC), either pristine or contaminated with polychlorinated biphenyls (PCBs), by an organohalide respiring marine microbial community and its biotransformation activity towards PCBs sorbed on MPs, in anaerobic laboratory microcosms of a marine sediment. All MPs were rapidly colonized by the microbial community within 2 weeks of incubation, when approximately 10¹⁰ 16S rRNA gene copies cm^-² were detected on PVC, 10⁹ copies cm^-² on PE, and 10⁸ copies cm-² on PET, PP and PS. A greater biofilm growth on PVC pellets than other MPs was confirmed by quantification of the reducing sugars of the EPS and biofilm staining with crystal violet. Illumina sequencing of the 16S rRNA genes and Principal Coordinate Analysis (PCoA) revealed that the biofilm community on MPs significantly differed from the sediment community, being enriched of chemoorganotrophic fermenting species, and was significantly affected by the type of polymer. The presence of sorbed PCBs did not significantly affect the overall community composition, and mainly resulted in the enrichment of Dehalococcoidia, i.e., of the organohalide respiring members of the community. Reductive dechlorination of PCBs sorbed to MPs was observed after 2 weeks of incubation, when the average number of chlorines per biphenyl molecule was reduced from 5.2 to 4.8-4.3, and was faster (35.2 ± 1.9 to 61.2 ± 5.8 μmol of Cl removed kg_MP^-¹ week^-¹) than that of sediment-sorbed ones (33.9 ± 9.1 μmol of Cl removed kg_sediment^-¹ week^-¹), which started only after 10 weeks of incubation. These data suggest that microbial colonization of contaminated MPs might change the composition of sorbed PCB mixtures and therefore the toxicity associated to PCB-polluted MPs.

Keywords: Biofilm; Marine sediment; Microbial community; Microplastics; Polychlorinated biphenyls; Reductive dehalogenation.

MeSH terms

Anaerobiosis
Biodegradation, Environmental
Biotransformation
Geologic Sediments
Microbiota*
Microplastics
Polychlorinated Biphenyls
RNA, Ribosomal, 16S

Substances

Microplastics
RNA, Ribosomal, 16S
Polychlorinated Biphenyls