Encapsulation and immobilization of papain in electrospun nanofibrous membranes of PVA cross-linked with glutaraldehyde vapor

Pineapple peel carboxymethyl cellulose/polyvinyl alcohol/mesoporous silica SBA-15 hydrogel composites for papain immobilization

“…Further increase of papain concentration would reduce extra enzyme molecules to expand its linking with the hydrogel by squeezing into those pore sites covered by the existing enzyme molecules, eventually resulting in the reduction of the enzyme activity (Pavlidis et al, 2012). Moreno-Cortez et al (2015) also observed the similar change in the immobilization of papain on the PVA nanofibers. Hence, 3 mg/mL of papain concentration is adequate.…”

“…After 10 days of storage, the immobilized papain retained nearly 79% of its initial activity, whereas the free enzyme only retained about 27%. Obviously, it is different from mesoporous silica immobilization, the covalent bonds between enzyme and the hydrogel, formed by the cross-linking reaction with glutaraldehyde, contributed higher conformational stability to the immobilized papain, thus ensuring higher shelf-life than free papain (Moreno-Cortez et al, 2015;Wu, Yuan & Sheng, 2005). …”

“…During cross-linking reaction, glutaraldehyde is commonly used as a favorable crosslinker for enzyme immobilization due to its high reactivity toward the amine and hydroxyl groups (Moreno-Cortez et al, 2015;Wang et al, 2014). However, it is generally known that the cross-linking reaction can influence the activity of immobilized enzymes by affecting accessibility of substrate to active site of the immobilized enzyme, in some cases, cross-linking even causes inactivation of enzymes (Wu, Yuan & Sheng, 2005).…”

“…However, industrial applications of free enzymes are still hindered due to their difficulties in separation and reuse as well as low stability upon exposure to heat, extreme pH values and organic solvents . Compared with free enzymes, immobilized enzymes significantly provide many important advantages such as reusability, rapid termination of reaction (easy separation from the reaction solutions) and enhanced stability (Li, Ding & Zhou, 2013;Moreno-Cortez et al, 2015).…”

“…Until now, hydrogels based on natural or synthetic polymers, such as cellulose (Wu et al, 2014), chitosan (Yang et al, 2016), alginate (Mohammed et al, 2015), gelatin (Chen et al, 2014), carrageenan (Evingür & Pekcan, 2013;Long et al, 2015) and polyvinyl alcohol (PVA) (Moreno-Cortez et al, 2015;Song et al, 2016) have aroused considerable interest as unique support materials for enzyme immobilization.…”