Ultrasound processing of amyloglucosidase: impact on enzyme activity, stability and possible industrial applications

Abstract

This study evaluated the effect of ultrasound processing as a pre-treatment of amyloglucosidase on the enzymatic activity and stability. The activity was evaluated under optimal (65°C/ pH = 4.5) and non-optimal conditions of temperature and pH and its stability was evaluated during storage at 8°C. The enzyme solution was processed at 9.5 W L-1, 40 kHz, 23°C and at pH 3.5, 4.5, and 5.5, for up to 120 min. The activity was measured at 35, 65 and 80°C. The US process was able to increase, reduce or not alter the enzymatic activity, depending on the conditions applied. These modifications depended on the pH of the enzyme solution, the ultrasound processing time and the activity temperature. In different ultrasound conditions, mainly at 35 and 65°C, the enzyme activity did not change, demonstrating that this technology can be used for other purposes, such as microbial inactivation, without affecting the enzyme. The activity increase (up to 15%) occurred under non-optimal pH and temperature conditions (pH 3.5 or 5.5/ 80°C), suggesting that ultrasound promoted stabilization and enzymatic protection. This result is interesting in the starch saccharification, which requires the enzymatic reaction at high temperatures. Therefore, such results can increase the application range of this enzyme in different industrial applications.

Preparation of layer‐assembled W/O/W‐type microencapsulated beads and application in solid‐state fermentation

“…The microcapsule beads were subjected to different conditions of temperature (30–100°C), pH (2–11), and ethanol concentration (1%–15%) for 1 h and measured the residual glucoamylase activity of microcapsule beads (Soares et al., 2020). The untreated glucoamylase activity was defined as 100%, and the retentive glucoamylase activity of microcapsule beads after treatment with different conditions was calculated according to the following equation: $$$$\begin{eqnarray}&& {\mathrm{retentive\ glucoamylase\ activity}}/{\mathrm{\% }} =\nonumber\\ && \frac{{{\mathrm{residual\ glucoamylase\ activity}}}}{{{\mathrm{glucoamylase\ activity\ without\ treatment}}}}\ \times 100\end{eqnarray}$$$$…”

“…The microcapsule beads were subjected to different conditions of temperature (30-100 • C), pH (2-11), and ethanol concentration (1%-15%) for 1 h and measured the residual glucoamylase activity of microcapsule beads (Soares et al, 2020). The untreated glucoamylase activity was defined as 100%, and the retentive glucoamylase activity of microcapsule beads after treatment with different conditions was calculated according to the following equation:…”

Ultrasound-Assisted Intensification of Activity of Free and Immobilized Enzymes: A Review

“…In the case of pepsin at a short treatment time, the enzyme configuration may be denatured as less activity was observed as compared to the untreated enzyme, but it can renature to its native state at prolonged treatment time (60 min). Soares et al 55 also investigated the effect of ultrasound on enzyme pretreatment. Amyloglucosidase was pretreated under different ultrasound conditions in an ultrasonic bath reactor.…”

“…Free lipase and ultrasonicated lipase marked a gradual decrease in residual enzyme activity to 68% and 66%, respectively. Soares et al 55 studied the effect of ultrasonication on amyloglucosidase stability. The reactor used for sonication was a bath type.…”