Immobilization of antimicrobial trypsin inhibitors onto cashew gum polysaccharide/PVA films

In this work, films produced by blending cashew gum polysaccharide (CGP) with PVA were used as support for immobilization of trypsin inhibitors with antimicrobial activity obtained from Platypodium elegans (PeTI) and Inga laurina (ILTI). The produced films had a homogeneous macroscopic surface with an absence of bubbles and cracks. SEM of CGP/PVA confirmed the porous structure of these materials, being observed a high incidence of pores with a diameter ranging from 0.4 to 7 mu m after swelling in a solution with basic pH. CGP/PVA-F2 presented improved mechanical properties when compared with CGP/PVA-F1, showing higher values of tensile strength and elongation. Results from immobilization efficiency proved that both CGP/PVA formulations were able to entrap trypsin inhibitors. However, the inhibitory activity of the immobilized PeTI was two-fold higher than that observed for ILTI, independently of the film formulation. The release profile of PeTI was similar in both formulations, with an increase in the amount of released inhibitor as a function of time. For ILTI, the CGP/PVA-F2 presented higher release than that from CGP/PVA-F1, achieving a maximum release after 720 min. Also, the released inhibitors showed high stability after 24 h of storage. This study confirmed that CGP/PVA films are versatile and efficient materials to be used as support for immobilization of biomolecules. (C) 2019 Elsevier B.V. All rights reserved.