Abstract: “Polyhydroxyalkanoates (PHAs) – biodegradable biocompatible polyesters of microbial origin – are among the most promising materials, which can be used in various areas. The authors’ collection of highly productive strains and original technologies were used to synthesize PHAs. Biodegradation behavior of two PHAs, poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate), was studied in natural environments (soils, freshwater ecosystems, marine environments) of different climatic zones. PHAs are degraded in all studied environments but their biodegradation is influenced by the chemical structure of the polymer, its geometry and the technique used to process it, climate, weather, and the type of the natural ecosystem. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) has been used to design experimental sustained-release formulations of different pesticides in the form of pellets, films and microgranules. The kinetics of polymer degradation and the dynamics of model pesticide (i”

Keywords: polyhydroxyalkanoates, biodegradable polymers, biodegradation, pesticides, slow release forms