Physiochemical Characterization of α-Amylase as Crosslinked Enzyme Aggregates

Starch is promising candidate material for enhancing the catalytic activity of α-amylase during the crosslinking process. To help meet industrial needs, here we tested the influence of bovine serum albumin (BSA) and starch on the performance of crosslinked α-amylase aggregates (CLEA), α-amylase-prepared as CLEA with starch (CLEA-S), and BSA (CLEA-BSA). Our results showed that the activities of CLEA, CLEA-S, and CLEA-BSA were 1.1-, 1.0-, and 0.74-fold higher than the free α-amylase, respectively. The stability of the immobilized enzyme slightly changed. After immobilization, the enzyme increased its pH and temperature ranges with the optimal pH values of 5.5, 7.5, 5.5, respectively for CLEA, CLEA-S, and CLEA-BSA, and an upper temperature limit of 50 °C for all three immobilized forms. Among the three immobilized forms, the CLEA-S was the most thermostable, losing only 3% of its initial activity during 390 min incubation at 50 °C. Our microscopic observations of CLEA-S showed that porous structures were formed and such structures could help substance diffusion. In addition, there was excellent affinity between CLEA-S and the substrate. The results suggest that CLEA-S have great potential for industrial application, including for use in starch-based alcohol fermentation.

Physiochemical Characterization of α-Amylase as Crosslinked Enzyme Aggregates Journal Articles