Hydrolysis of maltoheptaose in flow through silicon wafer microreactors containing immobilised alpha-amylase and glycoamylase

In this study,a silicon micro immobilised enzyme reactor (mu IMER) has been applied for hydrolysis of maltoheptaose as a model maltodextrin and starch using immobilised otamylase (from Aspergillus oryzae) and glycoamylase (from Aspergillus niger). The influence of several parameters was investigated such as immobilisation chemistry, buffer constituents, pH, temperature, flow rate and substrate concentration. The conversion efficiency profile of the substrate was measured and the long-term stability of the reactor was tested. For separation and detection of the formed hydrolysis products, high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was used. The results show that the mu IMERs can also be used for hydrolysis of starch and also additionally be connected directly on-line with, e.g., liquid chromatography, making it possible to perform on-line characterisation and analysis of starch hydrolysis products.