Carboxypeptidase A immobilization with zeolitic imidazolate framework for enhancement of ochratoxin A degradation ability

Figures & data

Figure 1. TEM images for ZIF-8 preparation: (A) Reaction for 2 min; (B) Reaction for 10 min; (C) Reaction for 24 h.

Figure 2. TEM images for materials calcination: (A) ZIF-8; (B) CPA/PVP/ZIF-8; (C) ZIF-8 composites after calcination; (D) CPA/PVP/ZIF-8 composites after calcination.

Figure 3. (A) Fourier transform infrared (FT-IR) spectra of samples; (B) PXRD patterns of ZIF-8 and CPA/PVP/ZIF-8 composites; (C) N₂ adsorption-desorption isotherm for ZIF-8 and CPA/PVP/ZIF-8 composites; (D) BJH pore size distribution for ZIF-8 and CPA/PVP/ZIF-8 composites.

Figure 4. Comparison of the degradation ability of free enzyme and complex enzyme under the optimum incubation conditions.

Figure 5. Stability optimization (A) pH stability; (B) temperature-stability; (C) organic reagent content; (D) repeated cycles.

Table 1. Detection of OTA degradation rate in different control groups by ELISA kit (n = 3).

Time (h)	Samples
	Control		CPA		CPA/PVP/ZIF-8		CPA + ZIF-8		ZIF-8
	Rate%	RSD%	Rate%	RSD%	Rate %	RSD %	Rate %	RSD %	Rate %	RSD %
1	3.33	1.66	43.29	0.48	22.94	0.88	48.59	1.42	14.87	1.14
3	2.07	2.92	45.06	2.05	39.89	1.30	49.28	1.47	18.93	2.16
6	4.63	1.62	45.45	0.78	54.77	1.31	49.97	0.93	21.62	1.68
9	3.34	2.54	45.51	0.69	67.46	0.81	50.69	1.68	23.09	1.71
12	5.90	2.14	45.95	1.09	74.23	1.68	51.73	1.18	23.39	1.50
24	4.64	1.29	46.06	1.54	76.75	1.03	52.49	1.61	23.11	0.51

Table 2. Detection of OTA degradation rate in different control groups by UPLC.

Time (h)	Samples
	Control		CPA		CPA/PVP/ZIF-8		CPA + ZIF-8		ZIF-8
	Rate%	RSD%	Rate%	RSD%	Rate %	RSD %	Rate %	RSD %	Rate %	RSD %
1	3.02	1.34	42.69	1.25	21.95	0.39	48.39	0.67	15.68	1.77
6	4.73	0.44	44.89	0.37	56.33	1.08	52.15	1.34	22.93	1.59
9	4.85	0.43	46.52	1.11	69.22	0.43	53.82	0.31	24.36	1.83
12	4.94	0.31	46.76	1.18	76.28	0.77	54.10	1.13	24.76	0.92
24	4.81	1.18	47.49	0.68	80.06	0.66	54.37	0.92	25.02	0.47