Table 2 Estimation of pectinase specific activity produced by strain Rhodotorula mucilaginosa PY18 and mutants after 48 h incubation at 28 ℃

First step mutation with hydrogen peroxide (H2O2)* mutagenesis

Parent R. mucilaginosa PY18 strain

46.35

1.28

H-Mutants

 H-14

67.65

1.37

 H-36

69.48

1.06

 H-47

75.31

1.57

Second step mutation with ultra violet (UV) mutagenesis

Parent H-47

75.31

UV-mutants

 UV-31

91.87

1.67

 UV-42

83.12

1.44

Third step mutation with ethidium bromide (Eth.Br)** mutagenesis

Parent UV-31

91.87

E-Mutants

 E-37

47.89

0.87

 E-48

92.47

1.7.4

 E-54

114.2

1.82