Incubation period and agitation speed alter the activity of crude amylase produced by thermophilic bacteria isolated from Pulu Hotspring

Abstract

The purpose of this study was to determine the optimum condition in yielding crude amylase enzymes with the highest activity produced by PL-16, a thermophilic bacteria isolated from Pulu hot spring. The study was carried out using a completely randomized design with a varied incubation time of 0, 6, 12,18, 24, 30, 36, 42, 48, 54, 60, 66, and 72 hours, and agitation speed of 60, 90, 120, 150, 180, and 200 rpm. The activity of extracted crude amylase enzyme was determined using the DNS method and bacterial growth by measuring its Optical Density (OD600). The results showed that optimum amylase activity was at 48 hours incubation time with OD of 2.823 and activity of 0.437 U/mL. Furthermore, agitation speed of 180 rpm produced the highest amylase activity of 0.498 U/mL with an OD of 2.435. Pearson correlation test exhibited a positive and considerable strength of association between enzyme activity and bacterial growth. Our crude amylase showed higher activity after optimizing its production condition with 48 hours incubation and agitation speed of 180 rpm.