Optimization of cultural conditions such as medium, temperature and pH is
crucial for the production of enzymes (Cherry et al., 2004). Figure 2 indicates the effect
of different temperatures on α-amylase production. Accordingly, the growth of Bacillus
sp. WA21 and production of α-amylase was found optimum at 45°C thus, this
temperature was selected for further enzyme production studies. Asif et al., (2009)
reported 45°C as optimum temperature for the growth of Bacillus isolated from hot
spring. Our findings are in agreement with Vieille et al., (1996) who reported that
thermophiles produced optimally active enzyme at temperatures close to the producing
organism’s optimal growth temperature. Our results showed that the optimal conditions
for the cell growth were equally adequate for the enzyme production.