Fungal Communities Associated with the Biodegradation of Polyester Polyurethane Buried under Compost at Different Temperatures

Abstract

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25°C, 45°C, and 50°C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25°C, while at both 45°C and 50°C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future.

Review on the current status of polymer degradation: a microbial approach

“…Acetaldehyde forms during ether linkage conversion with the help of sulfate-reducing bacteria. Fusarium solani and Candida ethanolica were identified as dominant species on the surface of polyurethanes Zafar et al 2013). Curvularia senegalensis showed more degrading activity as compared to others (Howard 2002).…”

“…The gene for such enzymes encodes 548 amino acid protein and contains hydrophobic domains for polymer surface attachment, the catalytic domain, lipase box and signal sequence. In previous studies, bacterial species were less reported for PUR degradation in comparison to fungi, e.g., Arthrographis kalrae, Aspergillus fumigatus, A. niger, Emericella, Lichthemia, Fusarium solanii, Thermomyces, Corynebacterium sp., Neonectria, Plectosphaerella, Phoma, Nectria, Alternaria and P. aeruginosa, and bacteria from genera Bacillus and Comamonas also served as polyurethanes degrader (Shimao 2001;Chandra and Rustgi 1998;Flavel et al 2006;Zafar 2013;Akutsu et al 1998;Bhardwaj et al 2012b). Shah et al (2008a) isolated the bacteria from soil samples and examined them for polyurethane degradation.…”

“…Packaging applications, bottles, food wrappers, pipes (Zheng and Yanful 2005;Perez et al 2002;Liu et al 2011;Jeffrie 1994;Kwon et al 2009) Polyurethane Hetero-polymer Isocyanate and polyol 400 Fibers, foams, paints, coating, packaging (Zheng and Yanful 2005;Slade et al 1964;Zafar 2013;Zembouai et al 2014) (Zheng and Yanful, 2005;Sharma et al 2000;Flavel et al 2006;Nakayama et al 1991;Carvalheiro et al 2008;Mcalpine et al 2001) Polycarbonate Homo-polymer Carbonate…”

Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams

“…This material, however, is more recalcitrant to fungal attack than PS-PU (17). Although several works have documented the degradation of solid PS-PU by fungi (9)(10)(11)(12)(13)(14)17), scarce research on solid PE-PU biodegradation has been carried out. Early work reported that PE-PU foams were unaffected by Aspergillus niger and Cladosporium herbarum growth (18).…”

Degradação De Poliuretano Por Fungos: Perspectivas Para Preservação Ambiental

“…O PUR tem sido usado na fabricação de mangueiras, calçados, enchimento de móveis e tecidos, isolante térmico e acústico, sendo considerado um dos plásticos mais vendidos no mundo (MARQUES & MARTINS, 2009 (ZAFAR et al, 2013), uma vez que Cooney (1969) já havia demonstrado que a espuma de poliuretano poderia ser usada como uma matriz para a adesão do micélio do fungo. Esta suscetibilidade do Poliéster Poliuretano ao ataque de micro-organismos é facilitada devido à presença de ligações éster e uretano que são naturalmente vulneráveis à degradação enzimática (DARBY & KAPLAN, 1968).…”