Fig. 1

Schematic overview of β-mannanase and β-mannosidase display on the cell wall of S. cerevisiae for ethanol production from 1,4-β-d-mannan. For the yeast cell surface display of the protein of interest, the genes encoding a secretion signal sequence and an anchor protein (containing GPI anchor attachment signal sequence) are fused to the target gene so as to encode fusions at the N-terminus and C-terminus, respectively. In the present study, the β-mannanase and β-mannosidase fused with the Flo428 anchor protein are used for display on the yeast cell surface. After processing via the secretion pathway, the fusion proteins migrate to the cell surface and are tethered on the yeast cell wall following the removal of the GPI anchor at the cell membrane. The displayed β-mannanase and β-mannosidase enzymes can degrade 1,4-β-d-mannan, and the host then can assimilate the resulting mannose for fermentation to ethanol