Silica Sol-Gel Entrapment of the Enzyme Chloroperoxidase

Table 3

Properties of CPO sol-gel beads prepared with different casting buffers.

pH of casting buffer	4.5	5.5	6.5
BET surface area (m^2/g)	710 ± 40	740 ± 60	470 ± 40
Total pore volume (cm^3/g)	0.58 ± 0.02	0.60 ± 0.06	0.32 ± 0.04
Average pore diameter (nm)	3.3 ± 0.3	3.2 ± 0.1	2.7 ± 0.1
Activity (mIU)	251 ± 2	242 ± 29	161 ± 13
Specific activity (IU/mg)	157 ± 1	151 ± 18	100 ± 8
Activity compared to free CPO (%)^#	18	17	11
Cumulative leakage (%)^†	13	14	9

All data are presented as mean values ± one standard deviation of triplicate data sets. ^#The relative activity was based on a reference assay with free CPO in solution yielding 887 ± 31 IU/mg. ^†The cumulative leakage over ten days of maturation corresponds to the summation of the leakage data shown in Figure 8.