Robust process for high yield conversion of non-degradable polyethylene to a biodegradable plastic using a chemo-biotechnological approach

•Polyethylene (PE) can be converted to a biodegradable polymer –polyhydroxyalkanoate (PHA).•Process enables conversion of PE-derived fatty acids by bacteria to PHA.•Process was scaled to 20 L with high yields (83.0 g L-1 CDW with 65% PHA in 25 h).•LCA study finds that it is more beneficial to conver...

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Bibliographic Details
Published in:Waste management (Elmsford) 2021-11, Vol.135, p.60-69
Main Authors: Guzik, Maciej W., Nitkiewicz, Tomasz, Wojnarowska, Magdalena, Sołtysik, Mariusz, Kenny, Shane T., Babu, Ramesh P., Best, Marshall, O'Connor, Kevin E.
Format: Article
Language:English
Subjects:
Bioconversion
Fermentation
High cell density
Polyethylene
Polyhydroxyalkanoate
Pseudomonas putida
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Summary:•Polyethylene (PE) can be converted to a biodegradable polymer –polyhydroxyalkanoate (PHA).•Process enables conversion of PE-derived fatty acids by bacteria to PHA.•Process was scaled to 20 L with high yields (83.0 g L-1 CDW with 65% PHA in 25 h).•LCA study finds that it is more beneficial to convert PE to PHA, rather than PE incineration. In this study, the optimisation of a process for producing medium-chain-length polyhydroxyalkanoate (mcl-PHA) by Pseudomonas putida KT2440 when fed with a polyethene (PE)-derived fatty acid mixture was investigated. The PE was pyrolysed to produce a hydrocarbon wax that was subsequently oxidised to produce a mixture of fatty acids, purified, and used as a PHA substrate for the growth and selection of microorganisms. Based on the shaken flask screening, a production strain, i.e., Pseudomonas putida KT2440, was selected for conducting bioreactor studies. Feeding PE-derived fatty acids in a 20-L setup resulted in high mcl-PHA yields (83.0 g L−1 CDW with 65% PHA in 25 h). Furthermore, life-cycle assessment (LCA) was conducted to determine the environmental advantages of the proposed process and its impacts compared to those of other technologies for treating PE-derived waste streams. We conclude that processing waste PE into PHA, rather than incineration, produces biodegradable material while also reducing the additional emissions that arise from traditional PE waste treatment processes, such as incineration to gain energy.
ISSN:0956-053X
1879-2456
DOI:10.1016/j.wasman.2021.08.030