Comperative study of catalase immobilization on chitosan, magnetic chitosan and chitosan-clay composite beads

Figures & data

Figure 1. FTIR spectra of (A) a) chitosan, b) chitosan-clay, c) chitosan-clay-GA; (B) a) Fe₃O₄, b) chitosan-Fe₃O₄, c) chitosan-Fe₃O₄-GA.

Figure 2. The TGA curves of a) chitosan, b) chitosan-clay (1:1 chitoasn: clay) and c) chitosan-Fe₃O₄ beads (1:0.2 chitosan:Fe₃O₄).

Table I. Values of coupling yield, immobilization yield, and kinetic parameters (K_M and V_max) of free and immobilized catalase.

	Coupling yield (%)	Immobilization yield (%)	KM (mM)	Vmax (μmol/min)
Free-enzyme			14.28	3076.92
Chitosan	57.14	59.01	33.76	141.92
Chitosan-clay	60.71	65.49	30.33	176.6
Chitosan-Fe3O4	78.57	73.51	26.66	195.04

Figure 3. The effect of pH (A) and pH stability (B) (after 60 min.) on free and immobilized catalase (-▲-: free enzyme, -○-: immobilized catalase on chitosan, -●-: immobilized catalase on chitosan-clay, -◊-: immobilized catalase on chitosan-Fe₃O₄). Values are means of three replicates.

Figure 4. The effect of temperature (A) and temperature stability (B) (after 60 min.) on free catalase and immobilized catalase at pH 7.0 (-▲-: free enzyme, -○-: immobilized catalase on chitosan, -●-: immobilized catalase on chitosan-clay, -◊-: immobilized catalase on chitosan-Fe₃O₄). Values are means of three replicates.

Figure 5. Reusability of immobilized catalase on chitosan-clay (A) and chitosan-Fe₃O₄ (B) beads.