Biodeterioration and Biodegradation of Synthetic Polymers

Ho, Eggins; Mills, J.; Holt, A.; Scott, Gerald

doi:10.1016/b978-0-12-648050-4.50019-5

Cited by 27 publications

(9 citation statements)

References 4 publications

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“…More than 140 million tonnes of plastic was produced worldwide in 2001 (34), and the proportion of household plastic waste in the average American home increased from 3 to 5% of total waste in 1969 (15) to more than 30% in 1995 (21) and continues to rise. Many plastics are both physically and chemically robust and cause waste management problems (10).…”

mentioning

confidence: 99%

Fungal Communities Associated with Degradation of Polyester Polyurethane in Soil

Cosgrove

McGeechan²,

Robson

et al. 2007

Appl Environ Microbiol

156

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Soil fungal communities involved in the biodegradation of polyester polyurethane (PU) were investigated. PU coupons were buried in two sandy loam soils with different levels of organic carbon: one was acidic (pH 5.5), and the other was more neutral (pH 6.7). After 5 months of burial, the fungal communities on the surface of the PU were compared with the native soil communities using culture-based and molecular techniques. Putative PU-degrading fungi were common in both soils, as <45% of the fungal colonies cleared the colloidal PU dispersion Impranil on solid medium. Denaturing gradient gel electrophoresis showed that fungal communities on the PU were less diverse than in the soil, and only a few species in the PU communities were detectable in the soil, indicating that only a small subset of the soil fungal communities colonized the PU. Soil type influenced the composition of the PU fungal communities. Geomyces pannorum and a Phoma sp. were the dominant species recovered by culturing from the PU buried in the acidic and neutral soils, respectively. Both fungi degraded Impranil and represented >80% of cultivable colonies from each plastic. However, PU was highly susceptible to degradation in both soils, losing up to 95% of its tensile strength. Therefore, different fungi are associated with PU degradation in different soils but the physical process is independent of soil type.The worldwide production of synthetic polymers continues to rise, resulting in an increased environmental burden through the generation of plastic waste. More than 140 million tonnes of plastic was produced worldwide in 2001 (34), and the proportion of household plastic waste in the average American home increased from 3 to 5% of total waste in 1969 (15) to more than 30% in 1995 (21) and continues to rise. Many plastics are both physically and chemically robust and cause waste management problems (10). However, several families of plastics undergo biodegradation in the environment, and an understanding of how this degradation occurs may aid in the development of strategies to exploit these processes for waste management purposes.Microorganisms are responsible for the majority of plastic degradation (6), and abiotic factors such as photodegradation or hydrolysis play a very minor role (18,42). Plastics vulnerable to biodegradation include the polyhydroxyalkanoates, polycaprolactone, polylactic acid, polyvinyl chloride (31, 32), and polyester polyurethane (PU). PU is used in a variety of industrial applications, including insulating foams, fibers, and synthetic leather and rubber goods. The presence of ester and urethane linkages in the backbone of PUs makes them susceptible to hydrolysis by enzymes secreted by microorganisms, releasing breakdown products which may act as a carbon source and lead to a weakening of the tensile strength (1,13,22,26,27).Both PU-degrading fungi (5,6,12,32) and bacteria (1, 20, 23) have been isolated from PU, indicating that there are potential reservoirs of PU-degrading organisms widespread in the environment. It...

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mentioning

confidence: 99%

Fungal Communities Associated with Degradation of Polyester Polyurethane in Soil

Cosgrove

McGeechan²,

Robson

et al. 2007

Appl Environ Microbiol

156

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show abstract

“…A lack of clear, standardized definitions of degradability combined with poorly documented promotional claims left both legislators and the public confused about the merits of these products (10,21). Some of the confusion also stems from a lack of generally accepted measurement techniques concerning the environmental fate of plastics (11). The focus of early work in this field was deterioration that assessed usually undesirable changes in appearance and physical properties of plastics.…”

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confidence: 99%

Methods for Assessment of Biodegradability of Plastic Films in Soil

Yabannavar

Bartha

1994

Appl Environ Microbiol

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Traditional and novel techniques were tested and compared for their usefulness in evaluating biodegradability claims made for newly formulated "degradable" plastic film products. Photosensitized polyethylene (PE), starch-PE, extensively plasticized polyvinyl chloride (PVC), and polypropylene (PP) films were incorporated into aerobic soil. Biodegradation was measured for 3 months under generally favorable conditions. Carbon dioxide evolution, residual weight recovery, and loss of tensile strength measurements were supplemented, for some films, by gas chromatographic measurements of plasticizer loss and gel permeation chromatographic (GPC) measurement of polymer molecular size distribution. Six-and 12-week sunlight exposures of photosensitized PE films resulted in extensive photochemical damage that failed to promote subsequent mineralization in soil. An 8% starch-PE film and the plasticized PVC film evolved significant amounts of CO2 in biodegradation tests and lost residual weight and tensile strength, but GPC measurements demonstrated that all these changes were confined to the additives and the PE and PVC polymers were not degraded. Carbon dioxide evolution was found to be a useful screening tool for plastic film biodegradation, but for films with additives, polymer biodegradation needs to be confirmed by GPC. Photochemical cross-linking of polymer strands reduces solubility and may interfere with GPC measurements of polymer degradation.

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“…Ditmar: Ft. that was freshly isolated from plant seeds collected in a nearby prairie park. Biodeterioration of plastic products usually occurs by one of three mechanisms: (1) mechanical damage, e.g., rodent gnawing; (2) surface contamination, known as fouling; or (3) chemical breakdown [12]. It was beyond the scope of this project to determine which of the chemical ingredients of magnetic media are degraded by fungi.…”

Section: Discussionmentioning

confidence: 99%

Fungal colonization of computer diskettes and other magnetic media

McCain

Mirocha

1994

Mycopathologia

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Abstract. Computer diskettes can be colonized by saprophytic fungi, especially in the humid tropics.Fungi of the genera Alternaria, Aspergillus, Epicoccum, Paecilomyces, Penicillium, and Trichoderma were observed on diskettes from several tropical countries. Common saprophytic fungi from Minnesota colonized clean standard and high density diskettes in growth chambers, indicating that fungal contami~nation could occur wherever temperature and humidity were adequate. Fusarium species infested diskettes buried in garden soil in Minnesota. Audiotapes, videotapes, and computer magnetic tapes chemically resemble diskettes and also can be colonized by fungi, as can photographic film. The Mylar core of these magnetic media did not support the growth of Penicillium glabrum, the most aggressive fungus in diskette inoculation studies. However, growth of several fungal species was enhanced when the common plasticizer, lecithin, was added in powdered form to nutrient agar, suggesting that this ingredient of the diskettes may be metabolized by the fungi.

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Biodeterioration and Biodegradation of Synthetic Polymers

Cited by 27 publications

References 4 publications

Fungal Communities Associated with Degradation of Polyester Polyurethane in Soil

Fungal Communities Associated with Degradation of Polyester Polyurethane in Soil

Methods for Assessment of Biodegradability of Plastic Films in Soil

Fungal colonization of computer diskettes and other magnetic media

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