The bio-catalysed cleavage of ester bonds in poly(butylene succinate-co-hexane succinate) (PBSH) was studied with the aim to gain more underlying information about the degradation rules and differences in chloroform and tetrahydrofuran. Among various hydrolytic enzymes the lipase from Pseudomonas cepacia (PC) was chosen for the studies. The rules of enzymatic degradation were investigated by molecular weight variation and MALDI-TOF-MS analysis of the degradation products. Additionally

solvent effect and mechanism of the combination between substrate and enzyme were studied with molecular dynamics (MD) simulations and molecular docking. The results suggested that PBSH showed an obvious degradation both in chloroform and tetrahydrofuran. Particularly higher activity of PC lipase and greater degradation of PBSH were observed in chloroform. Molecular dynamics simulations data showed that root mean square fluctuation (RMSF) of the whole residues of PC lipase in tetrahydrofuran was greater than that in chloroform. In tetrahydrofuran

the solvent molecules could reach the active site and interact intensively with the active residues Ser87. This interaction destroyed the hydrogen bonding between Ser87 and His286. According to the results of molecular docking

the substrate containing hexane succinate (HS) docked more stably in the enzyme active site than butylene succinate (BS).