Hints at the Applicability of Microalgae and Cyanobacteria for the Biodegradation of Plastics

Abstract

Massive plastic accumulation has been taking place across diverse landscapes since the 1950s, when large-scale plastic production started. Nowadays, societies struggle with continuously increasing concerns about the subsequent pollution and environmental stresses that have accompanied this plastic revolution. Degradation of used plastics is highly time-consuming and causes volumetric aggregation, mainly due to their high strength and bulky structure. The size of these agglomerations in marine and freshwater basins increases daily. Exposure to weather conditions and environmental microflora (e.g., bacteria and microalgae) can slowly corrode the plastic structure. As has been well documented in recent years, plastic fragments are widespread in marine basins and partially in main global rivers. These are potential sources of negative effects on global food chains. Cyanobacteria (e.g., Synechocystis sp. PCC 6803, and Synechococcus elongatus PCC 7942), which are photosynthetic microorganisms and were previously identified as blue-green algae, are currently under close attention for their abilities to capture solar energy and the greenhouse gas carbon dioxide for the production of high-value products. In the last few decades, these microorganisms have been exploited for different purposes (e.g., biofuels, antioxidants, fertilizers, and ‘superfood’ production). Microalgae (e.g., Chlamydomonas reinhardtii, and Phaeodactylum tricornutum) are also suitable for environmental and biotechnological applications based on the exploitation of solar light. Can photosynthetic bacteria and unicellular eukaryotic algae play a role for further scientific research in the bioremediation of plastics of different sizes present in water surfaces? In recent years, several studies have been targeting the utilization of microorganisms for plastic bioremediation. Among the different phyla, the employment of wild-type or engineered cyanobacteria may represent an interesting, environmentally friendly, and sustainable option.

Angiogenic Modification of Microfibrous Polycaprolactone by pCMV-VEGF165 Plasmid Promotes Local Vascular Growth after Implantation in Rats

“…In the process of hydrolysis, the polymer chains of polyesters are destroyed, as a result of which the mechanical properties of the frameworks decrease and the mass loss gradually increases. The presence of microorganisms or eukaryotic cells significantly affects the rate of change in the molecular weight of polyesters [ 70 , 71 ]. The autocatalytic nature of degradation is caused by the local accumulation of acids released during polyester breakdown and is observed both in vitro and in vivo [ 72 , 73 ].…”

Effect of Time-Real Marine Environment Exposure on the Mechanical Behavior of FRP Composites

“…However, the microorganisms that settled on the coupon's matrix were causing mechanical changes on the organic resin [40], effectively creating voids from the surface and into the matrix; hence, additionally changing the mechanical properties of the composite. Since the polyester coupons were manufactured by hand layup, the number of imperfections and voids in the matrix was greater than in that of the vacuum-infused epoxy coupons.…”

Interplay of plastic pollution with algae and plants: hidden danger or a blessing?

“…Active assimilation involves specific carriers crossing the cytoplasmic membrane, and are usually coupled to catabolic pathways to oxidize plastics for energy and biomass production. Alternatively, plastics can be imobilized within algal cell walls or in the vacuole to prevent toxic effects on the cell (Barone et al, 2020). Furthermore, microalgae can form biofilms over plastics, actively inducing cracking and increasing its surface/volume and secrete degradative enzymes, which also helps reduce the plastics' molecular weight, facilitating the introduction of the molecules within the cell (see Section 4).…”