Biodegradação de biopolímeros: análise crítica das normas e avaliação da possível formação de microplásticos de PLA em diferentes ambientes

Abstract

This work addresses the biodegradation of polymeric materials from two complementary perspectives: a critical analysis of existing standards and an experimental evaluation of the behavior of a biopolymer under controlled conditions. Initially, the limitations of ASTM biodegradation standards are discussed, as they are predominantly based on carbon mineralization and do not consider intermediate stages of the process, such as material fragmentation and the potential formation of microplastics. This regulatory gap may result in materials being classified as biodegradable even in the presence of persistent polymeric residues. Subsequently, the experimental investigation of the biodegradation of a commercial product based on poly (lactic acid) (PLA), conducted with Pseudomonas aeruginosa in different culture media, demonstrated that degradation occurs slowly and incompletely, even after 180 days of incubation. Chemical and morphological characterization indicated surface alterations of the polymer, while residue analysis revealed the formation of particles compatible with microplastics throughout the process. Taken together, the experimental results corroborate the critiques raised regarding biodegradation standards, demonstrating that assessments based exclusively on CO₂ release are insufficient to describe the environmental fate of materials. Therefore, this work reinforces the need for complementary methodological approaches and for revising normative criteria to incorporate the identification and quantification of microplastics, ensuring more realistic and environmentally responsible evaluations of polymer biodegradation.