Immobilization of cross-linked cutinase aggregates onto magnetic beads for degradation of polycaprolactone

In this study, Pseudozyma jejuensis cutinase is immobilized on amino-functionalized magnetic supports by cross-linked enzyme aggregates (CLEA) for its use in bio-degradation of polycaprolactone (PCL). The amount of cutinase immobilized on the magnetic beads using glutaraldehyde as a coupling agent was measured to be 27 mg/g of beads 82% recovery of activity after immobilization. Compared to the free enzyme, the immobilized cutinase showed the optimum pH at 1 unit higher (pH 8.0) and also retained its enzymatic activity at higher temperatures. There was 55% retention of cutinase activity after 50 consecutive reuses, indicating its stability and reusability in aqueous media. Moreover, the immobilized cutinase maintained more than 80% of its initial activity during 20 days storage period, while the free cutinase reduced to 48% of initial activity under same condition. In addition, the immobilized cutinase showed a more significant increase in biodegradability over the free cutinase when the immobilized cutinase was used to degrade PCL in a batch system. Higher thermal and storage stability, as well as good durability after repeated use of the immobilized cutinase CLEA, highlights its potential applicability as large scale continuous systems for the enzymatic degradation of PCL.