Pullulanase pretreatment of highly concentrated maltodextrin solution improves maltose yield during β-amylase-catalyzed saccharification.

Increasing the substrate concentration can effectively reduce energy consumption and result in more economic benefits in the industrial production of maltose, but this process remarkably increases the viscosity, which has a negative effect on saccharification. To improve saccharification efficiency, pullulanase is usually employed. In the conventional process of maltose production, pullulanase is added at the same time with β-amylase or later, but this process seems inefficient when the substrate concentration is high. Herein, a novel method was introduced to enhance the maltose yield under high substrate concentration. The results indicated that the pullulanase pretreatment of highly concentrated maltodextrin solution for 2 h greatly affects the final conversion rate of β-amylase-catalyzed saccharification. The maltose yield reached 80.95 %, which is 11.8 % above the control value. Further examination confirmed that pullulanase pretreatment decreased the number of branch points of maltodextrin and resulted in a high content of oligosaccharides. These linear chains were suitable for β-amylase-catalyzed saccharification to produce maltose. This research offers a new effective and green strategy for starch sugar production.