Improved features of a highly stable protease from Penaeus vannamei by immobilization on glutaraldehyde activated graphene oxide nanosheets

Co‐immobilization of cellulase and glucose oxidase on graphene oxide by covalent bonds: a biocatalytic system for one‐pot conversion of gluconic acid from carboxymethyl cellulose

“…[26][27][28] The spectrum of GO-CEL-E/N-GA-GOD shows the band characteristics associated with the amide group, mainly the occurrence of 1658 cm −1 (C O), 3100-3500 cm −1 (N-H stretching), 1550-1640 cm −1 (N-H bending), 1458 cm −1 (C-N stretching) has indicated covalent attachment GOD. 29,30 The morphology of the GO sample was characterized using AFM ( Fig. 3), it was known that the GO size diameters as-prepared in the detection interval were all below 1 μm, The average thickness of GO prepared in this experiment was 1.214 nm, which was consistent with that of monolayer GO in previous reports.…”

“…In addition, the immobilized enzyme had a certain improvement in pH stability in an acidic environment, which may be concerned with the pH dependence of the GO carrier itself, in an acidic medium, the carboxyl groups at the edge of GO were protonated and hydrophobicity property of GO was enhanced. The proton concentration in the microenvironment of the immobilized enzyme was lower than that in the solution …”

“…The proton concentration in the microenvironment of the immobilized enzyme was lower than that in the solution. 23,30 Combining the optimal temperature and pH of free and immobilized enzymes, it can be seen that the optimal temperature and pH of GO-CEL-E/N-GOD were consistent with Immobilized-GOD, which may be due to the dominant position of GOD in activity of the biocatalytic system. The process of GO-CEL-E/N-GOD for coinstantaneous conversion CMC to gluconic acid by one-pot was studied (Fig.…”

“…The peaks around 2900 cm −1 can be caused by the symmetric and antisymmetric stretching vibrations of C‐H aliph groups in CEL . The spectrum of GO‐CEL‐E/N‐GA‐GOD shows the band characteristics associated with the amide group, mainly the occurrence of 1658 cm −1 (CO), 3100–3500 cm −1 (NH stretching), 1550–1640 cm −1 (NH bending), 1458 cm −1 (CN stretching) has indicated covalent attachment GOD …”

Parameters necessary to define an immobilized enzyme preparation

“…Hence some biocatalysts that are apparently unsuitable may become very adequate for the target process if it requires using different and potentially more severe conditions (98,99,112,113). The important point is that if the study has been properly undertaken, then it will be known that this improved activity is due to an improvement of the enzyme stability because under milder conditions for the enzyme, the real negative effect of the immobilization on the enzyme activity has already been determined (97,98,99,112,113,114).…”