KAIST Uncovers Divergent Fates of Biodegradable Plastics and Identifies Potential Microbial Degraders in Landfill Leachate (IMAGE)
Caption
Figure 3. Mesophilic anaerobic biodegradation in landfill leachate: Contrasting degradation of PHB, PLA, and PBAT and biofilm formation on PLA.
This figure summarizes the long-term anaerobic biodegradation of PHB, PLA, and PBAT in landfill leachate at 35 °C, together with changes in the physical appearance and surfaces of the plastic films.
Upper left: An anaerobic biodegradation test based on ISO 14853 was used to quantify the conversion of plastic-derived carbon into biogas. PHB reached 99.9% mineralization within 17 days. PLA exhibited an initial lag of approximately 20 days before gradually reaching 83.6% after 320 days. PBAT showed negligible mineralization, comparable to that of conventional LDPE.
Bottom: Photographs and scanning electron microscopy (SEM) images illustrate corresponding changes in film structure. PHB underwent extensive disintegration within a short period, PLA developed cracks, erosion, and surface damage more gradually, and PBAT showed little visible change after prolonged incubation.
Upper right: After 90 days of PLA incubation, dense biofilms composed of rod-shaped microorganisms were observed on damaged polymer surfaces. This observation illustrates the close association between surface microbial colonization and the substantial PLA degradation measured during the prolonged mesophilic anaerobic incubation.
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