Richard Gattin

Polylactic acid (PLA) remains poorly mineralized under mesophilic conditions relevant to home and decentralized composting. This study assessed whether bioaugmentation with Amycolatopsis orientalis, protein-based biostimulation with skimmed milk powder, or their combined application could enhance the mineralization of compression-molded amorphous PLA fragments at 28 °C in activated vermiculite. Closed respirometric bioreactors were monitored for 90 days, and the PLA mineralization extent was calculated from the cumulative CO₂ evolution after correction using treatment-specific blanks. The recovered PLA fragments were further analyzed by FTIR-ATR and DSC to provide complementary physicochemical monitoring. The final mineralization remained low, reaching 1.19 ± 1.88% for bioaugmentation, 3.49 ± 1.82% for biostimulation, and 8.75 ± 4.31% for the combined treatment. The combined treatment gave the highest mean value, which was significantly higher than bioaugmentation alone, but the individual biological replicates followed heterogeneous trajectories. In particular, BABS-3 reached 13.19% mineralization, indicating that higher responses can occur at the individual bioreactor level, although they were not consistently reproduced. FTIR-ATR and DSC revealed treatment- and replicate-dependent physicochemical changes but did not provide evidence of extensive bulk PLA transformation. These results contrast those of previous reports of higher PLA mineralization under warmer, mature compost conditions, emphasizing the complexity of the combined influence of temperature and matrix. Overall, the tested strategies were insufficient to achieve effective home compostability of PLA at 28 °C.

The demand for patient-specific medicine is steadily increasing, particularly with the need for innovative materials capable not only of supporting tissue regeneration but also accelerating it. The aim of this study was to develop a new printable composite material exhibiting ductile behavior, in contrast to brittle failure, in order to support cell growth even under structural compromise. PBS was selected as a blending component with PLA due to its enhanced biocompatibility for bone tissue regeneration. Both neat PLA and the PLA/PBS blend were subsequently combined with BaTiO₃, processed into filaments, 3D printed, and subjected to mechanical testing. PLA-based composites demonstrated higher stiffness under compression, with up to a 6.5% increase in Young’s modulus compared to the blended samples. However, the incorporation of PBS resulted in a more ductile response, as evidenced by three-point bending tests, even at BaTiO₃ concentrations of 10 wt%. This improved ductility is expected to provide safer conditions for cell growth and enable elastic recovery following mechanical loading.

The demand for patient-specific medicine is growing, particularly with the need for innovative materials that can not only support tissue regeneration but also accelerate it. This study aimed to develop a new printable composite material exhibiting ductile behavior, as opposed to brittle failure, to support cell growth even in the event of structural compromise. PBS was selected in this study to be blended with PLA due to its higher biocompatibility for bone tissue regeneration[1]. Both neat PLA and the PLA/PBS blend were then mixed with BaTiO3, printed and tested by mechanical testing. PLA-based composites demonstrated higher stiffness under compression, with up to 6.5 % higher in Young’s Modulus compared to the blended samples. However, the incorporation of PBS resulted in a more ductile material, as evidenced by 3-point bending tests, even at BaTiO3 concentrations of 10 wt%. This ductility should provide safer conditions for cell growth and allow elastic recovery after mechanical loading.

Plastic pollution, largely driven by packaging waste, calls for sustainable alternatives. This study investigates biodegradable thermoplastic biocomposites based on PLA, PBS, and PBAT, incorporating 10 wt.% of agro-industrial filler-brewers’ spent grain (BSG) and orange peel (OP) without compatibilization. The biocomposites were produced by melt extrusion followed by thermo-compression. A full factorial design was implemented to assess matrix–filler interactions and compare biocomposites to pure polymer fragments. OP particles, smaller and rougher than BSG, exhibited a higher specific surface area, influencing composite morphology and behavior. The OP slightly plasticized PLA, possibly due to volatile release during processing, whereas BSG increased stiffness in PBS and PBAT. Both fillers reduced mechanical strength, especially in PLA, due to limited interfacial adhesion, and significantly decreased PLA’s thermal stability. The addition of fillers also increased water sorption and modified the sorption kinetics of the three main modes (Langmuir-type, Henry’s law sorption, and water molecule clustering), as well as the values of the half-sorption diffusion coefficients (D₁ and D₂), with notable differences between the OP and BSG linked to their structure and composition. These findings provide a better understanding of structure–property relationships in biodegradable composites and highlight their potential for sustainable packaging and other industrial applications.