Production and properties of alpha-amylase from thermophilic Bacillus sp.

Abstract

α-amylase (1,4-α-D-glucan glucanohydrolase, EC 3.2.1.1) production by thermophilic Bacillus sp strain SMIA-2 cultivated in liquid media containing soluble starch reached a maximum at 48h, with levels of 57U/ mL. Studies on the α-amylase characterization revealed that the optimum temperature for activity was 70ºC. The enzyme was stable for 2h at 50ºC, while at 60ºC, 70ºC and 90ºC, 4%, 13% and 38% of the original activities were lost, respectively. The optimum pH of the enzyme was 7.5. After incubation of crude enzyme solution for 24h at pH 7.5, a decrease of about 5% of its original activity was observed. The enzyme was strongly inhibited by Co 2+ , Cu 2+ and Ba 2+ , but less affected by Ca 2+ , Mg 2+ , Ni 2+ , Sr 2+ and Mn 2+. The enzyme in 1M and 5M NaCl solutions the enzyme retained 70% and 47% of the original activity after 24h of incubation at 4ºC, respectively.

Partial characterization of amylases of two indigenous Central Amazonian rhizobia strains

“…The amylase enzyme produced by the Rhizobium strain retained up to 94% of its original activity at pH 7.5, while the enzyme from the Bradyrhizobium strain had a loss of 16% (Figs 3 and 4). Similar results have been found in other studies (Cordeiro et al, 2002;Gupta et al, 2003;Sajedi et al, 2005).…”

“…3). A similar result was reported by Cordeiro et al (2002) for an amylase produced by Bacillus sp. The optimum pH for amylase activity from the Bradyrhizobium strain was also 7.5 (Fig.…”

“…(Stamford et al, 2001), Bacillus sp. (Cordeiro et al, 2002) and in Rhodothermus marinus (Gomes et al, 2003). There was no significant correlation between amylase production and total extracellular protein for either rhizobia strains (Table 1).…”

Purification and Characterization of α-Amylase from Bacillus subtilis Isolated from Cassava Processing Sites

“…Inactivating agents such as heat impair their native conformation so affecting their catalytic functions. It has been reported that most amylases Bacillus spp have an optimum temperature of around 40-70°C [35].…”

“…The α-amylase activity was stimulated/activated by Na + and Zn 2+ ions correspondingly, Al 3+ and K + ions exhibited varied degree of inhibition while Ca 2+ and Hg 2+ ions caused total inhibition on α-amylase activity. The salt tolerance test is important in saccharification of starch and in treatment of effluent with high salinity containing starch or cellulose residues in pollution control mechanism [35,36]. Metallic ions can either show the inhibitory or stimulating effect on the activity of enzymes depending on the concentration of the metallic salt solution.…”