Efficient yeast surface-display of novel complex synthetic cellulosomes

Hongting Tang,Jiajing Wang,Xiaoming Bao,Dina Petranovic,Yu Shen,Shenghuan Wang,Jin Hou

doi:10.1186/s12934-018-0971-2

Hongting Tang, Jiajing Wang + Show 5 more

Open Access

https://doi.org/10.1186/s12934-018-0971-2

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Abstract

BackgroundThe self-assembly of cellulosomes on the surface of yeast is a promising strategy for consolidated bioprocessing to convert cellulose into ethanol in one step.ResultsIn this study, we developed a novel synthetic cellulosome that anchors to the endogenous yeast cell wall protein a-agglutinin through disulfide bonds. A synthetic scaffoldin ScafAGA3 was constructed using the repeated N-terminus of Aga1p and displayed on the yeast cell surface. Secreted cellulases were then fused with Aga2p to assemble the cellulosome. The display efficiency of the synthetic scaffoldin and the assembly efficiency of each enzyme were much higher than those of the most frequently constructed cellulosome using scaffoldin ScafCipA3 from Clostridium thermocellum. A complex cellulosome with two scaffoldins was also constructed using interactions between the displayed anchoring scaffoldin ScafAGA3 and scaffoldin I ScafCipA3 through disulfide bonds, and the assembly of secreted cellulases to ScafCipA3. The newly designed cellulosomes enabled yeast to directly ferment cellulose into ethanol.ConclusionsThis is the first report on the development of complex multiple-component assembly system through disulfide bonds. This strategy could facilitate the construction of yeast cell factories to express synergistic enzymes for use in biotechnology.

Highlights

The self-assembly of cellulosomes on the surface of yeast is a promising strategy for consolidated bioprocessing to convert cellulose into ethanol in one step
Design of synthetic scaffoldins and cellulosomes instead of cohesins and dockerins (Coh–Doc) from bacterial cellulosomes, the protein pair of Aga1p and Aag2p was used for synthetic yeast cellulosome construction, which was assembled through covalent bonds (Fig. 1)
The repeated N-terminal fragment of Aga1p was fused with a cellulose-binding domains (CBD) domain from Trichoderma reesei and displayed on the yeast cell surface through the Aga1p C-terminal domain to construct a synthetic scaffoldin named ScafAGA3 (Fig. 1a). This synthetic scaffoldin was used as the primary scaffoldin or anchor scaffoldin

Summary

Introduction

The self-assembly of cellulosomes on the surface of yeast is a promising strategy for consolidated bioprocessing to convert cellulose into ethanol in one step. Tang et al Microb Cell Fact (2018) 17:122 low Other approaches such as increasing the cohesin by using two scaffoldins instead of one could improve the assembly efficiency of cellulases [12, 16]. Despite progress in this field, the direct conversion of cellulose into ethanol using yeast cellulosomes remains challenging, while the limitations including the low scaffoldin display level, the inefficient self-assembly of cellulases on scaffoldin, and the low activity of cellulases

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