Screening and Characterization of Thermostable Amylase-Producing Bacteria Isolated from Soil Samples of Afdera, Afar Region, and Molecular Detection of Amylase-Coding Gene

Table 4

The effect of metal divalent cations on crude amylase from the three isolates. Each value represents the mean of three independent assays.

Metal ion	Concentration (mM)	Residual activity (%)
		M13	M8	M2
Ca	1	91.1	91.6	90.4
	5	93.3	106.3	110.2
	10	108.5	88.4	86.7
Mg	1	85.4	84.5	83.6
	5	79.3	81.5	80.7
	10	76.9	78.3	77.6
Zn	1	48.3	50.2	48.5
	5	19.5	20.7	24.6
	10	17.8	18.4	20.7
None		100	100	100