Isolation and identification of a feather degrading Bacillus tropicus strain Gxun-17 from marine environment and its enzyme characteristics

Table 5 Effect of various metal ions on the keratinase

Metal ion	Concentration (M)	Residual activity (%)	Metal ion	Concentration (M)	Residual activity (%)
None	–	100.00 ± 4.75^bc
Na²⁺	0.025	96.00 ± 9.64^bcd	Si²⁺	0.025	114.76 ± 9.21^b
	0.25	79.38 ± 5.55^cde		0.25	116.05 ± 4.77^b
	2.5	74.97 ± 2.05^cde		2.5	57.48 ± 1.81^ef
Mn²⁺	0.025	102.97 ± 22.35^bc	Co²⁺	0.025	91.58 ± 11.57^bcd
	0.25	260.72 ± 15.56^a		0.25	43.89 ± 6.27^fg
	2.5	236.62 ± 23.84^a		2.5	40.86 ± 4.03^fg
Mg²⁺	0.025	84.25 ± 0.64^cde	Al³⁺	0.025	96.87 ± 1.25^bc
	0.25	83.33 ± 1.87^cde		0.25	11.17 ± 1.16^h
	2.5	57.89 ± 0.98^ef		2.5	21.53 ± 6.69^gh
Ca²⁺	0.025	84.25 ± 5.00^cde	Cu²⁺	0.025	− 0.37 ± 0.87^h
	0.25	75.28 ± 12.16^cde		0.25	7.73 ± 2.64^h
	2.5	10.45 ± 5.13^h		2.5	6.61 ± 2.07^h
K⁺	0.025	83.74 ± 5.12^cde
	0.25	80.20 ± 0.62^cde
	2.5	67.43 ± 2.40^def

Superscript letter(s) a, b, c, d, e, f, g and h down the column were used to indicate significant difference at P < 0.05

ISSN: 1472-6750