Influence of varying surface hydrophobicity of chitosan membranes on the adsorption and activity of lipase

Abstract

ABSTRACT:The hydrophobic surface modification of chitosan membranes was performed using the amidating reaction of amino groups on a membrane surface with stearic acid activated by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). The varying surface hydrophobicity of chitosan membranes was achieved by changing the degree of amidation and evaluated by the water contact angle analysis and the adsorption experiment of the hydrophobic dye, Rose Bengal. The effects of the surface hydrophobicity of chitosan membranes on the adsorption behaviors, activity and stability of Candida rugosa lipases were investigated. The experimental results suggested that the increased surface hydrophobicity of chitosan membranes improved the adsorption capacity and activity of the immobilized lipase. The modified chitosan membranes with 30.36% amidation exhibited the maximum activity retention of 83.87%. In addition, a desirable thermal stability was also achieved for the adsorbed lipase.

Conversion of biomass to selected chemical products

“…362 The hydrophobisation of chitosan was achieved either by grafting hydrophobic chains by amidation of chitosan with carboxylic acids (Fig. 16), 363,364 or by N-alkylation of chitosan with alkyl bromide. 365 However, the amino group should be preserved to keep the biocide activity of chitosan which requires that hydrophobic chains be grafted by esterification or etherification reactions with the OH groups.…”

Enzyme immobilization on/in polymeric membranes: status, challenges and perspectives in biocatalytic membrane reactors (BMRs)

“…The authors explain this by reduced biocompatibility of the membrane, but another explanation could be that too hydrophobic membranes cause higher enzyme loadings. 64 Such high enzyme loadings are known to cause molecular crowding, which results in enzyme deactivation. 19,35,65 Although adsorption is caused by rather weak interactions, a lot of enzymes are stabilized by these interactions and their optimal process conditions can be changed by them (Table 3).…”

Fabrication of a blood compatible composite membrane from chitosan nanoparticles, ethyl cellulose and bacterial cellulose sulfate

“…This might be owing to hydrophobic –CH 2 of chitosan exposed on the surface of CEB. 42 CE3 and CE4 had same WCA due to their CN amount and the morphology were similar (shown in Table 1 ). Comparing CE and CEB membranes, the WCA of CEB was lower than CE membranes, indicating CEB had better hydrophilicity.…”