Electrospun polyvinyl alcohol/bovine serum albumin biocomposite membranes for horseradish peroxidase immobilization

• PVA/BSA/HRP biocomposite scaffold was fabricated by electrospinning.
• Effects of GTA treatment, BSA and PVA concentration on protein loading were explored.
• BSA improved stability, reusability and activity retention of the immobilized HRP.
• Residual activity of the immobilized HRP was 73% after 11 cycles of reuse.
• Immobilization of HRP into PVA/BSA membranes decreased substrate inhibition.

Electrospinning, a simple and versatile method to fabricate nanofibrous supports, has attracted attention in the field of enzyme immobilization. Biocomposite nanofibers were fabricated from mixed PVA/BSA solution and the effects of glutaraldehyde treatment, initial BSA concentration and PVA concentration on protein loading were investigated. Glutaraldehyde cross-linking significantly decreased protein release from nanofibers and BSA loading reached as high as 27.3% (w/w). In comparison with the HRP immobilized into the nascent nanofibrous membrane, a significant increase was observed in the activity retention of the enzyme immobilized into the PVA/BSA biocomposite nanofibers. The immobilized HRP was able to tolerate much higher concentrations of hydrogen peroxide than the free enzyme and thus the immobilized enzyme did not demonstrate substrate inhibition. The immobilized HRP retained ∼50% of the free enzyme activity at 6.4 mM hydrogen peroxide and no significant variation was observed in the KM value of the enzyme for hydrogen peroxide after immobilization. In addition, reusability tests showed that the residual activity of the immobilized HRP were 73% after 11 reuse cycles. Together, these results demonstrate efficient immobilization of HRP into electrospun PVA/BSA biocomposite nanofibers and provide a promising immobilization strategy for biotechnological applications.

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