Attachment of potential cultivable primo-colonizing bacteria and its implications on the fate of low-density polyethylene (LDPE) plastics in the marine environment

• Published in: Journal of hazardous materials Vol. 451; p. 131124
• Main Authors: Bitalac, Justine Marey S., Lantican, Nacita B., Gomez, Norchel Corcia F., Onda, Deo Florence L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05-06-2023
• Subjects: Bacteria - genetics; Biodegradation, Environmental; LDPE; Manila Bay; Marine environment; Philippines; Plastic-attached bacteria; Plastics; Polyethylene - chemistry; Primo-colonization; RNA, Ribosomal, 16S - genetics; Spectroscopy, Fourier Transform Infrared; Philippines; Marine environment; Manila Bay; LDPE; Plastic-attached bacteria; Primo-colonization
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.131124

Plastics released in the environment become suitable matrices for microbial attachment and colonization. Plastics-associated microbial communities interact with each other and are metabolically distinct from the surrounding environment. However, pioneer colonizing species and their interaction with the plastic during initial colonization are less described. Marine sediment bacteria from sites in Manila Bay were isolated via a double selective enrichment method using sterilized low-density polyethylene (LDPE) sheets as the sole carbon source. Ten isolates were identified to belong to the genera Halomonas, Bacillus, Alteromonas, Photobacterium, and Aliishimia based on 16S rRNA gene phylogeny, and majority of the taxa found exhibit a surface-associated lifestyle. Isolates were then tested for their ability to colonize polyethylene (PE) through co-incubation with LDPE sheets for 60 days. Growth of colonies in crevices, formation of cell-shaped pits, and increased roughness of the surface indicate physical deterioration. Fourier-transform infrared (FT-IR) spectroscopy revealed significant changes in the functional groups and bond indices on LDPE sheets separately co-incubated with the isolates, demonstrating that different species potentially target different substrates of the photo-oxidized polymer backbone. Understanding the activity of primo-colonizing bacteria on the plastic surface can provide insights on the possible mechanisms used to make plastic more bioavailable for other species, and their implications on the fate of plastics in the marine environment.
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•Sediment bacteria isolated from Manila Bay were able to utilize LDPE as the sole carbon source.•Bacterial clusters modified different moieties in the polymer backbone.•Attachment and proliferation of bacterial cells on the plastic surface were observed.•Surface deterioration of the LDPE film was observed as shown by roughness, pits, and crevices.