Biodegradace směsí PLA/PHB ve vodném termofilním anaerobním prostředí

Abstract

This work investigates the biodegradation of PLA poly(lactid-Acid) and blend PLA with polyhydroxybutyrate (PBH) in an environment of mesophilic (37°C) and thermophilic (55°C) anaerobic sludge. The thermophilic anaerobic sludge was prepared in a laboratory from mesophilic sludge sourced from a municipal waste water treatment plant and placed under thermophilic conditions. It was confirmed that PLA failed to decompose under mesophilic anaerobic conditions, while the degree of biodegradation achieved under thermophilic conditions more than 80%. The blend of PLA / PHB was under anaerobic thermophilic conditions almost completely decomposed, but under anaerobic mesophilic conditions, the decomposition rate corresponded approximately representation of PHB in the mixture. Abiotic hydrolysis of blend PLA/PBH in an environment of phosphate buffer (pH 7) at 55°C reached 23.8%, leading to the conclusion that hydrolytic enzymes present in thermophilic anaerobic sludge are involved in the biodegradation process as well as abiotic hydrolysis.