The Effect of Wheat Flour in Enhancing and Stabilizing Intracellular and Extracellular Bacillus licheniformis 5A5 -amylase Activity

The effect of wheat flour on the enhancement of -amylase activity was studied. Crude intracellular and extracellular Bacillus licheniformis 5A5 -amylases were treated with different wheat flour concentrations (5-20%) for 1-5 days at 4°C. Maximum specific activities were obtained after 4 days at 20% wheat flour addition (183 and 135 U mg, respectively). This addition protected the enzymes completely during lyophilization and was considered as a partial purification step. The results were confirmed using a Rapid Visco Analyzer, where 1000 U ml of partially purified enzyme led to near complete degradation of raw maize starch (4 g/40 mL) after 10 min. Noticeable splitting of some maize and wheat starch granules, also complete lysis of others was observed by scanning electron microscopy during the incubation of wheat starch granules with the enzyme for only 30 min. SDS gel electrophoresis showed that the wheat flour had removed and added new protein bands to the lyophilized enzyme molecule and the disappearance of bands through the purification steps led to a big loss in enzyme activities. Thermal stability of the pure -amylases was studied in the presence and absence of 0.01% (w/v) wheat flour filtrate. _____________________________________________________________________________________________________________