BACKGOUNDTo date, it has been challenging to determine the optimal proportions of the individual cellulases in crude extracts and multienzyme systems to promote enzyme synergism. The application of single surface-display of enzymes may obviate such challenges. This article presents a proof of concept of the optimal mixing of single surface-displayed cellulases for cellulose hydrolysis using Simplex lattice mixture design. RESULTSThe recently discovered maximized autotransporter-mediated expression system was used to express the three cellulases. The biochemical screening analysis revealed that the enzymes have a broad range of functional pH (4-9) and temperature (30-100 degrees C) characteristics. The evaluated optima were pH6 and 60 degrees C. Through the statistical design of experiment, a blend ratio of 1: 1.6: 1.4 of endoglucanase: exoglucanase: -glucosidase was identified as the sweet spot' for optimum sugar yield. The application of this blend generated about 0.354mgmL(-1) and 0.446mgmL(-1) of sugars from filter paper (O 6mm, approximate to 2.5mg) and 2.5% pretreated EFB, respectively, within 12h. Supplementing the enzyme blend with CaCl2 and Tween 20 improved the sugar yield. CONCLUSIONThis research has revealed an interesting concept of efficiently addressing cellulase synergism. The overall outcome of this research is promising for the derivation of value from lignocellulose. (c) 2018 Society of Chemical Industry