Biodegradation of oxo‐biodegradable polyethylene

Abstract

Biodegradation of polyethylene and oxobiodegradable polyethylene films was studied in this work. Abiotic oxidation, which is the first stage of oxobiodegradation, was carried out for a period corresponding to 4 years of thermo-oxidation at composting temperatures. The oxidation was followed by biodegradation, which was achieved by inoculating the microorganism Pseudomonas aeruginosa on polyethylene film in mineral medium and monitoring its degradation. The changes in the molecular weight of polyethylene and the concentration of oxidation products were monitored by size exclusion chromatography and Fourier transform infrared (FTIR) spectroscopy, respectively. It has been found that the initial abiotic oxidation helps to reduce the molecular weight of oxo-biodegradable polyethylene and form easily biodegradable product fractions. In the microbial degradation stage, P. aeruginosa is found to form biofilm on polymer film indicating its growth. Molecular weight distribution data for biodegraded oxo-biodegradable polyethylene have shown that P. aeruginosa is able to utilize the low-molecular weight fractions produced during oxidation. However, it is not able to perturb the whole of the polymer volume as indicated by the narrowing of the polymer molecular weight distribution curve toward higher molecular fractions. The decrease in the carbonyl index, which indicates the concentration of carbonyl compounds, with time also indicates the progress of biodegradation.

Biodegradation of Polyethylene by a Soil Bacterium and AlkB Cloned Recombinant Cell

“…Reddy et al [27] revealed that the β-carbons of hexadecane were oxidized repetitively into carboxylic acid groups and the alkane chain was cleaved by way of the formation of the acetyl-coenzyme A.…”

Comparison of the biodegradability of various polyethylene films containing pro-oxidant additives

“…This type of experiments allows a better understanding of the process fundamentals, while it could also become the basis of standardised, easy to reproduce tests. Biodegradation with defined microbial strains was evaluated in several studies, most recently with Pseudomonas aeruginosa strain [6,7]. The authors brought some rather qualitative evidences that bacteria used some substances from polyethylene to support their metabolism.…”

Investigating the degradability of polyethylene using starch, oxo‐material, and polylactic acid under the different environmental conditions

“…As a result, the study on environmentally friendly plastics became the interest of many research groups. [16][17][18] From the literature, it is suggested that the oxo-materials could reduce the degradability time of the plastics to 2-5 years in the United Kingdom. In the first method, plastics are made from renewable feedstocks such as polyhydroxyalkanoates and polylactic acid (PLA).…”

“…Fe2 + + ROO: + H + In the third step, by the reaction of radicals, the carbonyl groups could be produced. 17 In both researches, burying the samples underground could have significant effects on their decomposition. 18 There are many studies in the oxo-material degradability properties.…”