Effect of pH and temperature on recombinant enzymes. (a) Optimum pH of recombinant glucoamylase (■) and α-amylase (●); (b) pH stability of recombinant glucoamylase (■) and α-amylase (●); The optimal pH were studied between pH 3.0 and 9.0 at 60°C. The pH stability were determined after incubating enzymes at different pH buffers at 50°C for 30 min. (c) Optimum temperature of recombinant glucoamylase (■) and α-amylase (●); (d) Thermal stability of recombinant α-amylase (■60°C; ●70°C; ▲80°C); (e) Thermal stability of recombinant glucoamylase (■50°C; ●60°C; ▲70°C). The optimum temperature was monitored between 30°C and 90°C at pH 5.0. The thermostability was assayed after incubating the enzyme at different temperatures (50–80°C, pH 5.0). Samples were withdrawn per 5 minutes and placed on ice before the residual activities were assayed. All values were based on the average of triplicate measurements.