The Increase of Thermal Stability of A-Amylase from Locale Bacteria Isolate Bacillus Subtilis Itbccb148 by Chemical Modification with Dimethyladipimidate

Yandri*, Apriyanti, Tati Suhartati and S. Hadi*  

Department of Chemistry, Faculty of Mathematics and Natural Sciences University of Lampung, Bandar Lampung - 351 45 Indonesia.

Corresponding Author E-mail:yandrias@unila.ac.id 

ABSTRACT: The attempt to increase thermal stability of a-amylase from local bacteria isolate Bacillus subtilis ITBCCB148 was performed by chemical modification using dimethyladipimidate (DMA). The results showed that the native and modified enzymes with DMA (0.3%; 0.5%; and 0.7%) have a similar optimum temperature of 60°C. The thermal stability test done to the native and modified enzymes at 60°C and 60 minutes showed that the native enzyme have a residual activity of 7.7% and t1/2 of 15.4 min, while t1/2 of the modified enzymes were 23.9, 43.3 and 53.3 min. with residual activity of 15.9%, 35.5%, and 42.5, respectively. The chemical modification with DMA to a-amylase has shown to increase the thermal stability of the enzyme between 1.5 – 3.5 times compared to that of the native enzyme.

KEYWORDS: a-amylase; chemical modification; dimethyladipimidate; B. subtilis ITBCCB148

[ HTML Full Text]