The stability increase of α-amylase enzyme from Aspergillus fumigatus using dimethyladipimidate

Abstract

Abstract This study’s purpose is to improve the α-amylase enzyme’s stability from Aspergillus fumigatus applying dimethyladipimidate (DMA). It was conducted in different stages, including production, isolation, purification, modification, and the characterization of native and modified enzymes by the DMA addition. The enzyme activity was specified using the Fuwa and Mandels methods, while the protein level was conducted by the Lowry method. The results indicated that the native enzyme contains a specific activity of 7010.42 U/mg, with an increase of 7.8 times than the crude extract, which contains 904.38 U/mg. Meanwhile, the native enzyme contains an optimum pH of 5 at 55 °C, with residual activity of 17.17% after 60 min of incubation at 55 °C and a half-life of 25.86 min. After the DMA addition with 0.5, 1, and 1.5% concentration, the enzymes had 5.5 optimum pH and 65 °C temperature. Meanwhile, after 60 min of incubation at 65 °C, the modified enzymes had 54.17, 46.18, and 34.44% of residual activity, and 85.55 58.25 and 37.46 min of half-lives, respectively. This showed that the addition of DMA to the native α-amylase from A. fumigatus increased the stability of the modified enzymes by 1.5–3.3 times than the native enzyme.