Characterization and Potential Application of Bromelain from Pineapple (Ananas comosus) Waste (Peel) in Recovery of Silver from X-Ray Films

Table 2

pH stability of the enzyme at different preincubation periods.

pH value	Preincubation period
	0 h		3 h		6 h		12 h		24 h		48 h
	Gelatin removal time (seconds)	Residual activity (100%)	Gelatin removal time (seconds)	Residual activity (%)	Gelatin removal time (seconds)	Residual activity (%)	Gelatin removal time (seconds)	Residual activity (%)	Gelatin removal time (seconds)	Residual activity (%)	Gelatin removal time (seconds)	Residual activity (%)
3	370	100	410	90.24	492	75.20	630	58.73	827	44.74	1230	30.08
4	49	100	55	89.09	65	75.39	81	60.49	129	37.98	250	19.60
5	44	100	45	97.78	46	95.65	45	97.78	46	95.65	80	55.00
6	38	100	39	97.44	41	92.68	42	90.48	45	84.44	51	74.51
7	34	100	34	100	36	94.44	35	97.14	36	94.44	39	87.18
8	45	100	47	95.74	50	90.00	55	81.81	60	75.00	480	9.38
9	45	100	45	100	46	97.83	45	100	45	100	51	88.24
10	46	100	46	100	46	100	47	97.87	48	95.83	50	92
11	109	100	116	93.97	143	76.22	208	52.40	463	23.54	600	18.16

Residual activity = (activity of sample after incubation/activity of sample before incubation) × 100.