Pullulanase is important to enhance the production and quality of glucose from starch hydrolysis by mixed enzymatic saccharification. To improve glucose production, it would be necessary to manipulate the enzymatic saccharification process and conditions. For enzymatic saccharification involving the newly identified recombinant pullulanase, glucose, maltose and isomaltose were detected, and glucose was the main product from maltodextrin hydrolysis, with the dextrose equivalent value over 99.5%. During the saccharification process, there would be a balance between glucose and disaccharides due to enzymatic hydrolysis and its reverse reaction. With the optimised ratio of glucoamylase to pullulanase (50:1) and dry maltodextrin concentration (20%, w/w), the glucose content (DX) around 99% was obtained with the space-time yield of 6 mg g−1·h. After optimisation by orthogonal design and response surface methodology, the DX value of 99.35% was achieved with enzyme loading 75 U g−1 at 55 °C and pH 4.5 for 36 h.
A novel pullulanase was applied to the mixed enzymatic saccharification (MES) to enhance glucose production from maltodextrin hydrolysis. By adjustment of pullulanase amount and optimization of the MES conditions using orthogonal design and response surface methodology analysis, the DX value of 99.35% was achieved and an efficient saccharification process was developed for glucose production.