Effects of Engineered Saccharomyces cerevisiae Fermenting Cellobiose through Low-Energy-Consuming Phosphorolytic Pathway in Simultaneous Saccharification and Fermentation

• Published in: Journal of microbiology and biotechnology Vol. 32; no. 1; pp. 117 - 125
• Main Authors: Choi, Hyo-Jin, Jin, Yong-Su, Lee, Won-Heong
• Format: Journal Article
• Language: Korean
• Published: 한국미생물생명공학회 31.01.2022
• Subjects: cellobiose phosphorylase; Cellulosic ethanol; engineered Saccharomyces cerevisiae; mutant cellodextrin facilitator; simultaneous saccharification and fermentation; simultaneous saccharification and fermentation; Cellulosic ethanol; engineered Saccharomyces cerevisiae; mutant cellodextrin facilitator; cellobiose phosphorylase
• ISSN: 1017-7825; 1738-8872

Until recently, four types of cellobiose-fermenting Saccharomyces cerevisiae strains have been developed by introduction of a cellobiose metabolic pathway based on either intracellular β-glucosidase (GH1-1) or cellobiose phosphorylase (CBP), along with either an energy-consuming active cellodextrin transporter (CDT-1) or a non-energy-consuming passive cellodextrin facilitator (CDT-2). In this study, the ethanol production performance of two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-2 (N306I) with GH1-1 or CBP were compared with two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-1 (F213L) with GH1-1 or CBP in the simultaneous saccharification and fermentation (SSF) of cellulose under various conditions. It was found that, regardless of the SSF conditions, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the best ethanol production among the four strains. In addition, during SSF contaminated by lactic acid bacteria, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the highest ethanol production and the lowest lactate formation compared with those of other strains, such as the hydrolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-1 with GH1-1, and the glucose-fermenting S. cerevisiae with extracellular β-glucosidase. These results suggest that the cellobiose-fermenting yeast strain exhibiting low energy consumption can enhance the efficiency of the SSF of cellulosic biomass.