The aim of this study was to develop poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bionanocomposites with natural vermiculite (VMT) and modified vermiculite (VMTO), by the melt intercalation technique and to evaluate the thermal behavior, biodegradation, and food-packaging interactions through X-ray diffraction (XRD). Through XRD, we observed the structure of a microcomposite for the systems with natural clay and possibly an exfoliated structure for the systems with VMTO. We observed from the thermogravimetry and differential scanning calorimetry results that the natural systems showed a small increase in the thermal stability, whereas the organoclay systems had a lower thermal stability. A high biodegradability in the pure polymer and the natural bionanocomposites was evidenced by the Sturm test through the carbon dioxide production and high weight loss of the material. We observed that there was no significant migration of PHBV from the bionanocomposites to the simulants. Under these circumstances, the bionanocomposites with VMT presented better thermal stability and a high biodegradability and were possibly inert when in contact with food. (C) 2016 Wiley Periodicals, Inc.