Biodegradation of synthetic polymers. II. A limited microbial conversion of14C in polyethylene to14CO2by some soil fungi

摘要

AbstractPolyethylene film synthetized with a randomly distributed14C marker, was exposed to biodegradative impact by cultivated soil, a mixed culture of three wood rot fungi, andFusarium redolens, isolated from soil experiments. The net values of14CO2evolution obtained by scintillation measurements amounted for about 0.5 in two years when calculated as a percentage of the total amount of radioactivity in the test sample. Both the soil and the different mold cultures reflected with very good agreement a definite liberation of14CO2from the14C‐labeled polyethylene film, significantly above that produced abiotically from aging samples. This is interpreted as due to an enzymatic cleavage and oxidative conversion of synthetic polymeric or oligomeric alkanes with limited chain length, accessible for biodegradation. Abiotic parallel experimental series maintained in a similar way, but either on distilled water only, or on media completed with silvernitrate in order to inhibit microbial growth, revealed slow but consequently progressing—evidently nonenzymatic—conversion of14C to14CO2. This is referred to as a borderline case of as unarrestable tardy mineralization process in the absence of light, however, autocatalytic and oxidative, an aging procedure in restricted