Continuous production of maltotetraose using a dual immobilized enzyme system of maltotetraose-forming amylase and pullulanase

In order to produce a product with a high content of maltotetraose, dual-enzyme systems composed of immobilized maltotetraose-forming amylase (G(4)-forming amylase) and pullulanase were studied. The thermostability of individually immobilized enzymes was examined in continuous operation; studies revealed that the enzyme immobilized on "Chitopearl" was much more stable than that immobilized on Diaion HP-50. The effects of operating conditions on the stability of G(4) forming amylase immobilized on "Chitopearl" were examined to confirm that the apparent half-life data could be arranged using the immobilized enzyme stability factor, f(s). As for the dual immobilized enzyme system, six methods of usage were considered, with five yielding a 7-10% (w/w) higher content of maltotetraose product than the single-enzyme system. The effects of operating conditions on the maltotetraose production reaction were examined to confirm that the maltotetraose content of the products could be analyzed using the specific space velocity,SSV. In dual immobilized enzyme systems, pullulanase immobilized on the same carrier as the G(4)-forming amylase was found to be more stable than pullulanase immobilized on separate carriers. The effectiveness of using immobilized pullulanase along with the G(4)-forming amylase was confirmed from constant-conversion operations in which the maltotetraose content in the product was kept at 50% (w/w) in laboratory-scale experimentation.