ChemInformVolume 33, Issue 41 p. 290-290 Reviews Aerobic Biodegradation of Polymers in Solid-State Conditions: A Review of Environmental and Physicochemical Parameter Settings in Laboratory Simulations. Sophie Grima, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this authorVeronique Bellon-Maurel, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this authorPierre Feuilloley, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this authorFrancoise Silvestre, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this author Sophie Grima, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this authorVeronique Bellon-Maurel, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this authorPierre Feuilloley, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this authorFrancoise Silvestre, Cemagref, F-34033 Montpellier, Fr.Search for more papers by this author First published: 19 May 2010 https://doi.org/10.1002/chin.200241290AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume33, Issue41October 15, 2002Pages 290-290 RelatedInformation

For many years now, scientific articles have been published on the potential biodegradability of polyethylene. Polyethylene (PE) with peroxidant additives, in the form of agricultural films, is sold by various suppliers as biodegradable mulch. Even though, the photo-chemical and thermal degradation of these products under artificial laboratory conditions is highlighted, several extrapolation on the biodegradation and, moreover, on the neutral environmental impact of PE are made. In this study, three different commercial mulch films have been submitted to standardised biodegradation tests and the results are discussed. The first conclusions are that a very low degree of biodegradation of the commercial PE films is achieved from these tests and that crosslinked PE micro-fragments are found in soil after a very long period of time.

A new test method is described for assessing biodegradation of plastic material under simulated soil conditions. An inert substrate can be activated with soil extract and nutrient and used in place of soil in biodegradation tests. The biodegradation level is evaluated by determining the carbon dioxide (CO2) production released by the test reactors. Effects of substrate nature, solution pH, nutrient composition, soil extract concentration, and activation duration on CO2 production were investigated, and the experimental conditions were optimized. Results obtained with cellulose showed a biodegradation rate of 80% within 28 days. Moreover, with this kind of substrate, reaction products and residues can be easily extracted and analysed.

During the last few years, biodegradable polymers have been developed to replace petrochemical polymers. Until now, research devoted to these polymers essentially focused on their biodegradability. There is now a need to bear out their nontoxicity. To verify this, the biodegradation must be carried out in accelerated laboratory tests which allow the metabolites and residues to be recovered. To reproduce the natural conditions (compost, field) as closely as possible, degradation experiments must be run on solid-state substrates. We review studies of aerobic degradation in solid-state substrates. This article focuses in particular on the environmental, physical, and chemical parameters (such as substrate nature, moisture, temperature, C/N ratio, and pH) that influence biodegradation kinetics. This study also aims at finding the solid substrate most adapted to residues and metabolite recovery. The most significant parameters would appear to be the substrate type, moisture content, and temperature. Inert substrates such as vermiculite are well suited to residue extraction. This review also opens the field to new research aimed at optimizing conditions for aerobic solid-state biodegradation and at recovering the metabolites and residues of this degradation process.

La biodégradabilité représente un phénomène complexe, difficile à mesurer. De fait, les normes qui en fixent les conditions opératoires sont nombreuses. A l'heure actuelle, se dégage une tentative d'uniformisation à l'échelle de l'Union européenne.

In the present project, twenty materials (e.g., polyhydroxybutyrate-hydroxyvalerate, polycaprolactone, cellulose acetate, polyacticacid, polyethylene), representing varied biodegradability levels were studied. An aerobic respirometric test, based on the CEN Draft, was setup. The biodegradability of each plastic film was evaluated by measuring the percentage of carbon converted into CO2 during 35 days. The values of the CO2 production were plotted versus days as a cumulative function. In order to reduce its number of points, the cumulative curve was modeled using a sigmoïd function (Hill sigmoïd). This model was compared to one found in the literature. A χ i 2 test showed that the biodegradation curve was more accurately fitted with the model than the previous one. Three kinetic parameters were determined by this “Hill model”: one represents the maximal percentage of carbon converted into CO2, the second the “half-life time” in days of the degrading part of the material and the third one the curve radius.

This work validated a burial protocol for in situ testing and presents a robust, repeatable and time-saving technique to measure degraded areas in the sample, i.e. an image analysis method. 1440 specimens of degraded samples have been compiled in a data base. To this end, twenty samples presenting different levels of biodegradability (i.e. PHBV/HV, PLA, PCL, PCL-Starch, paper, PE, PE-Starch) were buried at 4 different locations and then disinterred at 4, 6, 9, 12, 18, and 24-month intervals. The biodegradation levels of these samples were determined by computing weight and area loss. Weight loss was measured after careful cleaning, whereas area loss was quantified using image analysis. Image analysis gives reliable information on visual pollution while only requiring a rudimentary and thus quicker cleaning of the samples.

Résumé : La biodégradation du polyéthylène fait l'objet de nombreuses publications et d'une pression commerciale de plus en plus forte. Pourtant, une analyse scientifique des résultats publiés fait apparaître de nombreuses imprécisions, incohérences ou lacunes dans les démarches employées qui permettent de mettre e n doute la réelle biodégradabilité de c e polymère a dditivé. Les questions qui restent en suspens s ont clairement exposées et la prudence dans l'utilisation de ce polymère additivé en agriculture est vivement recommandée dans l'attente de résultats plus probants. Abstract : The biodegradation of polyethylene is the subject of numerous publications and, moreover, specifically designed PE is the object of a strong commercial pressure. However, a scientific a nalysis of the available results highlights various inaccuracies, inconsistencies and deficiencies in the experimental approaches which cast doubt the effective biodegradability of this polymer. Open questions are clearly raised and care must be taken in the agricultural use of these additived polymer in the wait of convincing results.