Singh et al.

Table 3: Production of α- amylase by Bacillus licheniformis under different moisture

content of SSF medium

S.No

Moisture content (%)

Enzyme activity(IU)

1.

55

105.61

2.

60

119.17

3.

65

128.83

4.

70

153.76

5.

75

160.74

6.

80

171.89

7.

85

168.64

8.

90

141.48

r =0.765, tcal =2.88<ttab =2.44 at 5% (NS), Y = 1.51 X + 34.22

Figure 3. Variation of alpha amylase production by Bacillus licheniformis under

different moisture content of SSF medium

The critical importance of moisture level in SSF media and its influence on the

biosynthesis and secretion of enzymes can be attributed to the interference of

moisture in the physical properties of the solid particles. High moisture leads to

reduction in substrate porosity, changes in the structure of the substrate particles

and reduction of the gas volume that limits the oxygen transfer. Babu and

Satyanarayana (1995) also achieved a marked improvement in enzyme production

by optimizing moisture content in the medium when the moisture level was at the

ratios of 1:1.5.Similar results were also demonstrated in this study, where a high

amylase enzyme titer (171.89 IU) was recorded when the initial moisture level

was 80%. A reduction in enzyme production at high initial moisture content may

be due to a reduction in substrate porosity, changes in the structure of substrate

particles and reduction of gas volume. In addition, reduction in enzyme production

is due to low moisture content that causes a reduction in the solubility of nutrient

of the substrate and a low degree of swelling affecting the bacterial growth.

210

International Journal of Bioinformatics and Biological Sciences : v.2 n.3&4. Dec. 2014