Microbial Degradation of Marine Plastics: Current State and Future Prospects

The Potential Role of Marine Fungi in Plastic Degradation – A Review

“…Fungi are able to degrade synthetic compounds; e.g., persistent organic pollutants (POPs) (Singleton, 2001), polycyclic aromatic hydrocarbons (PAHs) (Cerniglia and Sutherland, 2001), benzene, toluene, ethylbenzene and xylenes (BTEX compounds) (Buswell, 2001) and pesticides (Pinto et al, 2012). The metabolic versatility of fungi and ability to degrade complex compounds indicates that biodegradation of plastics in the environment could be a potential metabolic trait of some fungi (Vaksmaa et al, 2021a). To date, some plastic degrading fungi have indeed been identified mostly from the Ascomycete phylum to which also Aspergillus, Fusarium, and Penicillium belong (Table 2 Fusarium sp.…”

“…SEM allows high magnification, thus offers high resolution at the nanometer range. SEMbased observations are used to examine and evaluate the colonization of plastic films or particles by microorganisms and to simultaneously visualize cracks, pits and deformations on the plastic surface (Zettler et al, 2013;Vaksmaa et al, 2021a), which in return can indicate if the polymer is degraded. SEM has been applied in several studies to investigate fungi on plastics, for example, to visualize the growth of C. tenuissimum and C. pseudocladosporioides hyphae within PE-PU foams (Álvarez-Barragán et al, 2016).…”

Merging Plastics, Microbes, and Enzymes: Highlights from an International Workshop

“…Moreover, plastic-degrading activities could be the promiscuity of certain enzyme classes that have their main activity on antique natural polymers (e.g., suberin and cutin, waxy compounds coating leaves) with chemical/physical features similar to those of plastics. However, the debate persists regarding whether microbial enzymes used to deconstruct natural plant polymers have had enough time to evolve and to adjust to equivalent functional groups present in durable plastics ( 26 ). In this sense, Dr. Öztürk pointed out that the natural evolution of environmental microorganisms to efficiently degrade plastic is likely to be very slow due to the recalcitrant nature of these polymers.…”

“…Lignin is a naturally occurring polymer that is relatively inert to degradation, being attacked only by wood-rotting fungi and some soil bacteria that have developed enzymatic strategies for its depolymerization ( 84 ). These lignin-degrading enzymes (e.g., peroxidases, laccases, and monooxygenases) might be candidates for the rational design of PDE (stated Dr. Bugg) ( 26 ). Lignin contains C-C and C-O bonds susceptible to enzymatic cleavage.…”

“…Although there is so far no solid study that has verified the microbial and enzymatic biodegradation of durable plastics in nature, apparently there are fewer plastics in oceans than expected (the "missing plastic" paradox). This observation suggests that natural biodegradation processes could occur or that a substantial sink for plastic debris could be found in marine sediments (10,26). Interestingly, there are some preliminary bioinformatic clues about the evolution and adaptation of putative PETases (i.e., PET hydrolases, enzymes that could hydrolyze PET) in global oceans (27).…”