Anaerobic Biodegradation of Polylactic Acid-Based Items: A Specific Focus on Disposable Tableware Products

Area of Science:

• Environmental Science and Engineering
• Polymer Science and Engineering
• Microbiology and Biotechnology

Background:

• Commercially available disposable tableware certified as compostable often presents end-of-life challenges.
• Bioplastics, such as polylactic acid (PLA)-based items, require specific treatment methods for sustainable disposal.
• Assessing the true biodegradability of bioplastics is complex and requires robust analytical approaches.

Purpose of the Study:

• To evaluate the viability of anaerobic degradation for compostable bioplastic tableware.
• To compare methods for quantifying biodegradation and correlate it with material properties and process conditions.
• To identify factors influencing the biodegradation kinetics and yields of polylactic acid-based products.

Main Methods:

• Testing of two polylactic acid-based bioplastic tableware types under mesophilic anaerobic digestion (38 °C) for 155 days.
• Advanced chemical characterization using microscopy, spectroscopy, and thermogravimetry.
• Comparison of biodegradation assessment via biogas production versus total organic carbon (TOC) removal; statistical analysis of influencing factors.

Main Results:

• Anaerobic degradation achieved high biodegradation degrees, ranging from 80.5% to 88.9%, as measured by TOC removal.
• TOC removal was identified as a more accurate method for quantifying biodegradation compared to biogas generation.
• Biodegradation patterns were found to be dependent on digestion temperature and the specific type of bioplastic material.

Conclusions:

• Anaerobic degradation is a viable end-of-life treatment for compostable bioplastic tableware.
• Total organic carbon removal provides a reliable metric for assessing bioplastic biodegradation.
• Understanding the interplay between bioplastic composition, digestion parameters, and biodegradation is crucial for optimizing waste management strategies.