Investigation and optimization of microbial amylase production

This study was investigated amylase production by a yeast isolate in different model media. The model media were prepared in three different cases with different plant and dairy waste materials. One group of model media prepared with tryptic soy broth (TSB), and the others were prepared with removing peptone and glucose from TSB. Samples were incubated for 24h, 48h and 72h, and then tested for amylase activity with DNS method. The highest amylase activity (1.38 U/mL) was obtained at 48h. The highest amylase activity was determined in model media containing peptone-free TSB and TSB with W4, respectively. Effect of incubation temperature, incubation time, agitation speed, substrate concentration, inoculum level, pH, medium volume were tested to find effective factors on amylase activity with Plackett-Burman statically design by using selected media (TSB with W4). Incubation temperature, time and agitation speed had significant effect on amylase activity. The optimization of amylase activity was performed by response surface methodology. Incubation temperature, time and agitation speed were chosen to optimize the amylase activity based on the Plackett-Burman design results. The results determined that maximum amylase activity (1.605 U/mL) was observed with temperature of 16°C, time of 36h, and rpm of 160. According to RSM results; validation of amylase activity was performed with following conditions: temperature of 14.9°C, time of 31h and agitation speed of 160 rpm and amylase activity was found as 1.130 U/mL.