Ulomoides dermestoides Coleopteran action on Thermoplastic Starch/Poly(lactic acid) films biodegradation: a novel, challenging and sustainable approach for a fast mineralization process.

Ulomoides dermestoides (UL) are macroinvertebrates insects belonging to Tenebrionidae Coleopteran family. They were used to hasten, in five days, the biodegradation-mineralization of thermoplastic starch (TPS)-poly(lactic acid) (PLA) films, otherwise biodegradable under composting conditions. After the contact of TPS-PLA film with UL for five days, TPS was metabolized and PLA was hydrolysed, as evidenced by decreasing of hydroxyl and carbonyl group peaks intensity by FTIR spectra, increasing of 13% of PLA crystallinity by DSC thermograms, reduction of PLA and TPS thermal stability by TGA analysis; faecal residues evidenced two glass transition temperature T, at 33 °C and 57 °C, associated with depolymerized TPS and PLA, respectively.

Structural changes of cassava starch and polylactic acid films submitted to biodegradation process.

Polylactic acid (PLA) and starch are compounds used in the manufacture of packaging to replace petroleum products as biodegradable and environmentally friendly materials. This study evaluated the structure and surface of a film manufactured by extrusion from cassava starch and PLA, which underwent a biodegradation process under compost conditions following the guidelines of ISO 4855-2:2007. Samples were taken every week for one month to perform Fourier Transform Infrared Spectroscopy (FT-IR) tests to identify functional groups on film, and High-Resolution Optical Microscopy (HROM) and Scanning Electron Microscopy (SEM) tests, from these techniques Structural changes in the film were evidenced.