Disposable Mater-Bi® bioplastic tableware. Characterization and assessment of anaerobic biodegradability

In this study commercial starch-based (Mater-Bi®) disposable bioplastic tableware items, which are among the most widely used commercial products available on the market, were selected for lab-scale anaerobic degradability tests. Since the knowledge of the biodegradation profile of bioplastic products is still incomplete, the study was aimed at investigating the maximum biodegradation potential of the materials under ideal anaerobic conditions, as well as the biodegradability degree as a function of treatment time. The experiments were carried out under mesophilic and thermophilic conditions at different food to microorganism ratios and test material sizes, and the specific biogas production and associated kinetics were evaluated. Biogas production was observed only under thermophilic conditions, with conversion yields in the range 602–898 mL/gTOC for the tested cups and 1207 ± 52.8 mL/gTOC for the knives. The degrees of biodegradation and disintegration were found to be strongly dependent on the product composition. Physical, chemical and morphological analyses were used to characterize the tested materials before and after the degradation and potential correlations among process parameters and bioplastic characteristics were derived.