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Biodegradation of synthetic polymers. III. The liberation of 14 CO 2 by molds like fusarium redolens from 14 C labeled pulverized high‐density polyethylene
Author(s) -
Albertsson AnnChristine,
Báanhidi Z. G.,
BeyerEricsson LiseLotte
Publication year - 1978
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1978.070221208
Subject(s) - biodegradation , polyethylene , aeration , high density polyethylene , chemistry , liberation , polymer , linear low density polyethylene , fusarium , organic chemistry , chromatography , materials science , chemical engineering , polymer chemistry , food science , botany , biology , biochemistry , engineering , in vitro
In model experiments based on aerated cultures of molds like Fusarium redolens , 14 C liberated from randomly labeled pulverized high‐density linear polyethylene (HPDE) with a specific surface of 10 m 2 /g appeared mainly in the form of respiratory 14 CO 2 . The quantity liberated in this case was slightly greater than that stemming from HDPE film, according to our previous report (0.56% by weight against less than 0.40%). Contaminations could be detected, especially after two years aeration in several culture jars. Two unidentified bacterial strains as well as Acremonium kiliense, Aspergillus versicolor , and Verticillium lecanii were all thriving on the sparse media and enhanced to some extent the degradative 14 CO 2 liberation, especially in mixed cultures together with F. redolens . Repeatedly close coincidence in 14 CO 2 development between experiments with somewhat shifting mixed microbial populations point to preference for test with mixed microbial cultures instead of one single pure culture. Such tests should, however, be based on species more likely to utilize hydrocarbons then the celluloses metabolizers often applied for test of plastics according to several internationally accepted prescriptions. Increased liberation of 14 CO 2 with decreasing particle size indicate that the accessibility of the metabolizable fractions of polyethylene must affect the degree of biodegradation. This is because with an increased surface/volume ratio in the plastic powders of decreasing mesh, more and more structurally hidden low molecular polyethylene material can be released and thus rendered accessible to the enzymes of attacking fungal hyphae. Also the possibility of an increased autooxidative scission of some of the long polymeric chains due to a “mastication effect,” as well as an autocatalytic type of oxidative deterioration caused by remnants of the silico‐alumina supported CrO 3 primary polymer catalyst must be considered in this connection, especially with regard to the general phenomenon of abiotic aging in the dark which was consistently registered by us.