Immobilization of Bacillus subtilis enzymes living on the surface of cotton

Carbon source	α-amylase (µmL-1)+ SE
Growth(Optical Density at 600 nm) +SE
Glucose	1.89±0.214	0.134±0.0001
Xylose	2.543±0.222	0.39±0.0003
Galactose	1.426±0,117	0,168±0,0001
Mannitol	0.244±0,020	0,022±1.74
Sucrose	1.58±0,020	0,161±0,0001
Fructose	1.94±0,052	0,138±0,0001
Lactose	1.601±0,23	0,358±0,0002
Starch	3.19±0,033	0,33±0,0002
Rice	2.243±0,106	0,365±0,0002
Flower	2.33±0,309	0,385±0,0003
Potato	2.238±0,153	0,259±0,0002

Table1. Effect of different carbon sources on α-amylase production and growth of Bacillus subtilis

The optimum concentration of starch for α-amylase production was 0.25 mg mL-1 with activity of 3.6 µ mL-1(Fig. 3,4). At the concentration of 0.375 mg mL-1 , the activity could be decreased or still constant, no change in the α-amylase production. Also at 0.125 mg mL-1 the activity will be increased until reached to 0.25 mg mL-1.

The optimum pH for α-amylase production was at pH 7 with activity 1.95 µ mL-1, (Fig. 5,6). The activity of α-amylase was decreased significantly at pH 9.0. The range of maximum growth was found from pH 5 to 8, respectively.

An optimum temperature for α-amylase production from Bacillus subtilis was 45°C (Fig. 7,8). At 50°C the activity was declined significantly. The range of maximum growth from 40 to 45°C, respectively.

The best nitrogen source for production of α-amylase from Bacillus subtilis was peptone with activity (2.71 µmL-1,) and the maximum growth measured with beef extract as shown in Table 2.