Direct fermentation of newspaper after laccase-treatment using yeast codisplaying endoglucanase, cellobiohydrolase, and β-glucosidase

Saccharomyces cerevisiae cannot utilize cellulose as a carbon source. In nature, cellulose is mainly degraded into glucose by 3 cellulases: endoglucanase II (EG), cellobiohydrolase II (CBH), and β-glucosidase I (BG). A yeast codisplaying these 3 enzymes was constructed by cell surface engineering to directly ferment cellulose into ethanol. The constructed yeast was used to directly ferment newspaper—a carbon source. The newspaper was first pretreated with Trametes sp. Ha1 laccase, and the laccase-treated newspaper was used for investigating the fermentation by the constructed yeast. The results indicated that the laccase-pretreated waste paper could serve as a resource for the production of ethanol by direct fermentation mediated by yeast codisplaying EG, CBH, and BG.

► Yeast codisplaying EG, CBH, and BG was constructed by cell surface engineering. ► A simple fermentation system was constructed at laboratory scale. ► Yeast codisplaying EG, CBH, and BG maximally fermented ethanol from newspaper.