Table 3 Estimation of keratinase specific activity produced by strain Streptomyces werraensis KN23 and its mutants after 48 h incubation at 37 °C

First step mutation with ultra violet (UV) mutagenesis

Parent S. werraensis KN23 strain

51.60

190 ± 0.045

1.052

UV-Mutants

U.V-14

59.87

185 ± 0.120

1.143

U.V-36

72.34

160 ± 0.011

1.247

U.V-39

66.90

170 ± 0.320

1.182

Second step mutation with hydrogen peroxide (H₂O₂)^a mutagenesis

Parent UV-36

72.34

160 ± 0.011

1.247

H₂O₂Mutants

H-7

91.07

135 ± 0.021

1.290

H-23

76.21

155 ± 0.178

1.249

H-42

74.43

150 ± 0.190

1.253

H-46

86.90

140 ± 0.167

1.265

Third step mutation with sodium azide (SA)^b mutagenesis

Parent H-7

91.07

135 ± 0.021

1.290

S.A-Mutants

S.A-14

49.80

110 ± 0.032

1.220

S.A-18

38.23

120 ± 0.078

1.086

S.A-26

35.01

120 ± 0.065

0.927

S.A-26

106.92

90 ± 0.231

1.437

S.A-31

46.24

115 ± 0.007

1.160