Colonization of Non-biodegradable and Biodegradable Plastics by Marine Microorganisms

Abstract

Plastics are ubiquitous in the oceans and constitute suitable matrices for bacterial attachment and growth. Understanding biofouling mechanisms is a key issue to assessing the ecological impacts and fate of plastics in marine environment. In this study, we investigated the different steps of plastic colonization of polyolefin-based plastics, on the first one hand, including conventional low-density polyethylene (PE), additivated PE with pro-oxidant (OXO), and artificially aged OXO (AA-OXO); and of a polyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), on the other hand. We combined measurements of physical surface properties of polymers (hydrophobicity and roughness) with microbiological characterization of the biofilm (cell counts, taxonomic composition, and heterotrophic activity) using a wide range of techniques, with some of them used for the first time on plastics. Our experimental setup using aquariums with natural circulating seawater during 6 weeks allowed us to characterize the successive phases of primo-colonization, growing, and maturation of the biofilms. We highlighted different trends between polymer types with distinct surface properties and composition, the biodegradable AA-OXO and PHBV presenting higher colonization by active and specific bacteria compared to non-biodegradable polymers (PE and OXO). Succession of bacterial population occurred during the three colonization phases, with hydrocarbonoclastic bacteria being highly abundant on all plastic types. This study brings original data that provide new insights on the colonization of non-biodegradable and biodegradable polymers by marine microorganisms.

Microbial Colonization in Marine Environments: Overview of Current Knowledge and Emerging Research Topics

“…Using aquaria filled with natural circulating seawater, Dussud et al [105] detected over 6 weeks the marine microorganisms associated with the successive phases of colonization, growing, and maturation of the biofilms developing on non-biodegradable [i.e., polyolefins such low-density PE, PE additivated with pro-oxidant (OXO)] compared to biodegradable polymers [i.e., artificially aged OXO (AA-OXO) and a polyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)]. All these substrates showed variable surface properties in terms of hydrophobicity and roughness.…”

Adhesion of Pathogenic Bacteria to Polystyrene, Skin and Gut Mucus of Gilthead Seabream, Infectious Capacity and Antibiotics Susceptibility

“…This study showed that all the tested bacteria adhered to polystyrene, 90% were moderately and strongly adherent. Many studies indicate that surface roughness influences bacteria adhesion (Lorite et al, 2011;Dussud et al, 2018). Baker and Greenham (1988) found that roughening the surface of either glass or polystyrene with a grindstone greatly increased the rate of bacterial colonization.…”

Micro-by-Micro Interactions: How Microorganisms Influence the Fate of Marine Microplastics

“…The functional groups that form on the surface of plastic during abiotic degradation (keto carbonyls, esters, vinyls and double bonds) (Restrepo-Flórez et al 2014) also change the hydrophobicity of the plastic surface (Fotopoulou and Karapanagioti 2015). The balance between the production and microbial consumption of these functional groups also affects the hydrophobicity of the plastic as degradation continues (Dussud et al 2018a).…”