Efficient yeast cell-surface display of an endoglucanase of Aspergillus flavus and functional characterization of the whole-cell enzyme.

Abstract

The endoglucanase gene endo753 from Aspergillus flavus NRRL3357 strains was cloned, and the recombinant Endo753 was displayed on the cell surface of Saccharomyces cerevisiae EBY100 strain by the C-terminal fusion using Aga2p protein as anchor attachment tag. The results of indirect immunofluorescence and Western blot confirmed the expression and localization of Endo753 on the yeast cell surface. The hydrolytic activity test of the whole-cell enzyme revealed that Endo753 immobilized on the yeast cell surface had high endoglucanase activity. The functional characterization of the whole-cell enzyme was investigated, and the whole-cell enzyme displayed the maximum activity at pH 8 and 50°C. The enzyme was stable in a pH range of 7.0-10.0. Furthermore, the whole-cell enzyme displayed high thermostability below 50°C and moderate stability between 50 and 70°C. These properties make endo753 a good candidate in bioethanol production from lignocellulosic materials after displaying on the yeast cell surface.