Relationship between Enzyme Adsorption and Enzyme‐Catalyzed Degradation of Polylactides

Abstract

The adsorption of proteinase K on PLLA and PDLA films was studied by CA, surface tension, and microscopic measurements. ESEM clearly shows that proteinase K can irreversibly adsorb on PLLA film. In contrast, no enzyme adsorption was detected on PDLA film under the same conditions. The CA of PLLA film rapidly decreases after immersion in Tris buffer containing proteinase K, whereas that of PDLA remains unchanged. These findings indicate that enzyme adsorption may be a prerequisite for enzymatic degradation of polylactide substrates. Surface tension measurements allow calculation of the average area occupied per proteinase K molecule. The results show that the enzyme molecules exhibit a more compact conformation at higher temperature.

Microcantilever sensors for fast analysis of enzymatic degradation of poly (d, l-lactide)

“…Li et al confirmed the observation of adsorption of enzyme on PLLA but observed no enzyme attachment on PDLA [48].…”

Catalysis as an Enabling Science for Sustainable Polymers

“…As for most enzymes, the efficiency of proteinase K at degrading semicrystalline polymers increases with decreasing crystallinity contents. For instance, crystalline PLA could not be degraded by proteinase K. , However, Wei and Li et al showed that proteinase K degraded PLLA faster than PDLA, mostly owing to higher adsorption of the enzyme at the surface of PLLA as compared to PDLA . In a thorough study on the influence of the chirality of PLA on the degradation activity of proteinase K, they also evidenced that LL, DL, and LD diads could be cleaved but not DD diads.…”

Combined effect of cellulose nanocrystals, carvacrol and oligomeric lactic acid in PLA_PHB polymeric films

“…It has been reported that this enzyme should be absorbed by the polylactide substrates in order to catalyze their hydrolytic degradation. The scission of the polymer chains preferentially occurs in the amorphous regions, getting progressively smaller segments (low molecular weight oligomers, dimers and monomers) that finally degrade into carbon dioxide and water (Zhao, et al, 2008;Wang, Fan & Hsiue, 2005). The main factors affecting the enzymatic degradation rate of PLA are molecular weight, hydrophilicity, degree of crystallinity, morphology, presence of additives and polymer blending (Tsuji, Echizen, & Nishimura, 2006).…”