Résumé
Polyhydroxybutyrate-co-valerate (PHBV) is a very promising bio-sourced and biodegradable bacterial polyester, the commercial development of which being limited by its high cost. On the other hand, olive oil extraction generates a large amount of lignocellulosic solid residue, called olive pomace (OP), whose disposal raises environmental concerns, including the inhibition of soil microbial populations and the reduction of seed germination. To address these issues, PHBV/OP based biocomposites were produced (at a filler content of 15 wt%) using three different fillers obtained by dry fractionation of OP, i.e. a stone-rich fraction (SF), a pulp-rich fraction (PF) and a crude pomace (FO). The objective of the present work was to investigate how the composition of OP-based fillers influenced the biodegradability of resulting biocomposites. The biodegradation of PHBV, OP-based fillers and OP/PHBV-based biocomposites was assessed by respirometric tests conducted in a standardized soil environment over 4 months. Results showed that the incorporation of OP-based fillers in PHBV favored the overall biodegradability of the materials. Indeed, 100% of biodegradation was achieved after 75, 79 and 87 days for PHBV-F0, PHBV-SF and PHBV-PF formulations respectively, while a biodegradation rate of only 91% was obtained after 123 days in the case of neat PHBV. These results were discussed in the light of several parameters such as the material structure, the affinity of the fillers for the matrix, the composition and the degree of crystallinity of the filler, together with the antibacterial activity of the OP samples assessed by a direct contact technique on solid medium. (C) 2019 Elsevier Ltd. All rights reserved.