Improving genetic immobilization of a cellulase on yeast cell surface for bioethanol production using cellulose.
In this study, Saccharomyces cerevisiae was genetically engineered to harbor the capability of utilizing celluloses for bioethanol production by displaying active cellulolytic enzymes on the cell surface. An endo-1,4-β-glucanase gene egX was cloned from Bacillus pumilus C-9 and its expression products, the EGX cellulases, were displayed on the cell surface of S. cerevisiae by fusing egX with aga2 that encodes the binding subunit of the S. cerevisiae cell wall protein α-agglutinin. To achieve high gene copies and stability, multicopy integration was obtained by integrating the fusion aga2-egX gene into the rDNA region of the S. cerevisiae chromosome. To achieve high expression and surface display efficiency, the aga2-egX gene was expressed under the control of a strong promoter. The presence of the enzymatically active cellulase fusion proteins on the S. cerevisiae cell surface was verified by carboxymethyl cellulase activity assay and immunofluorescence microscopy. This work presented a promising strategy to genetically engineer yeasts to perform efficient fermentation of cellulosic materials for bioethanol production.
State Key Laboratory of Heavy Oil Processing & Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, China.
Jinying
J
Yang
Hongyue
H
Dang
Jian Ren
JR
Lu
D001407:Bacillus / Q000201:enzymology / Q000235:genetics; D001709:Biotechnology / Q000379:methods; D061505:Cell Surface Display Techniques / Q000379:methods*; D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D015870:Gene Expression; D060847:Metabolic Engineering / Q000379:methods*; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
D004269:DNA, Bacterial; D011993:Recombinant Fusion Proteins; D000431:Ethanol; D002482:Cellulose; D002480:Cellulase