This study investigates the degradation of a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) compound under various environmental conditions. PHBV is a biodegradable, bio-based polymer with potential applications in packaging, medicine, and auto manufacturing. However, its use is limited by its brittleness, poor mechanical properties, and high cost. The research team conducted tests in natural environments (soil, home compost, freshwater, estuarine water, and seawater) and under controlled laboratory conditions (climate chamber, enzymatic degradation, aerobic and anaerobic composting). The study aimed to assess the degradation behavior of the PHBV-based compound, named T-PHBV, under different environmental factors. The results showed that degradation varied depending on the environment. In soil, T-PHBV bars experienced a mass loss of 6.6% after six months, while in estuarine mud, the loss was higher. In seawater, no significant visual or weight changes were observed after 12 months, except for biofouling. In home compost, T-PHBV films showed a mass loss of 8.74% after eight weeks and 43.81% after 12 weeks in river Elbe. Under aerobic composting conditions, T-PHBV granules became swollen and mouldy within six months. In anaerobic conditions, T-PHBV samples showed significant differences in degradation rate, with one sample losing 58% of its mass and another only 3.3%. Mechanical tests revealed that T-PHBV is a brittle material, with tensile properties decreasing significantly after two weeks of soil burial. The tensile modulus decreased by about 45%, stress by 60%, and strain by 15%. In seawater, the mechanical properties of T-PHBV decreased slowly, with a 50% reduction in tensile modulus after one year. In the climate chamber, the mechanical properties decreased more rapidly, with a 30% reduction in strain and stress within the first 78 hours. Spectroscopic analysis showed that the chemical structure of T-PHBV remained largely unchanged during degradation, with only minor changes in the infrared spectrum. Molecular analysis indicated a decrease in molecular weight, with a dramatic drop in the CC-aged samples after 50 hours. Thermal analysis showed that the thermal stability of T-PHBV remained unchanged after one year of immersion in seawater, with a single-step degradation profile observed. Morphological analysis using SEM revealed surface erosion and degradation of T-PHBV in various environments. The degradation was more pronounced in estuarine mud, where the surface became rough and showed numerous depressions. In seawater, the surface became rougher after six months, with the formation of voids and micro holes. The study concluded that PHBV degrades more rapidly in environments with higherThis study investigates the degradation of a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) compound under various environmental conditions. PHBV is a biodegradable, bio-based polymer with potential applications in packaging, medicine, and auto manufacturing. However, its use is limited by its brittleness, poor mechanical properties, and high cost. The research team conducted tests in natural environments (soil, home compost, freshwater, estuarine water, and seawater) and under controlled laboratory conditions (climate chamber, enzymatic degradation, aerobic and anaerobic composting). The study aimed to assess the degradation behavior of the PHBV-based compound, named T-PHBV, under different environmental factors. The results showed that degradation varied depending on the environment. In soil, T-PHBV bars experienced a mass loss of 6.6% after six months, while in estuarine mud, the loss was higher. In seawater, no significant visual or weight changes were observed after 12 months, except for biofouling. In home compost, T-PHBV films showed a mass loss of 8.74% after eight weeks and 43.81% after 12 weeks in river Elbe. Under aerobic composting conditions, T-PHBV granules became swollen and mouldy within six months. In anaerobic conditions, T-PHBV samples showed significant differences in degradation rate, with one sample losing 58% of its mass and another only 3.3%. Mechanical tests revealed that T-PHBV is a brittle material, with tensile properties decreasing significantly after two weeks of soil burial. The tensile modulus decreased by about 45%, stress by 60%, and strain by 15%. In seawater, the mechanical properties of T-PHBV decreased slowly, with a 50% reduction in tensile modulus after one year. In the climate chamber, the mechanical properties decreased more rapidly, with a 30% reduction in strain and stress within the first 78 hours. Spectroscopic analysis showed that the chemical structure of T-PHBV remained largely unchanged during degradation, with only minor changes in the infrared spectrum. Molecular analysis indicated a decrease in molecular weight, with a dramatic drop in the CC-aged samples after 50 hours. Thermal analysis showed that the thermal stability of T-PHBV remained unchanged after one year of immersion in seawater, with a single-step degradation profile observed. Morphological analysis using SEM revealed surface erosion and degradation of T-PHBV in various environments. The degradation was more pronounced in estuarine mud, where the surface became rough and showed numerous depressions. In seawater, the surface became rougher after six months, with the formation of voids and micro holes. The study concluded that PHBV degrades more rapidly in environments with higher