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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #327539
Title: Recycling carbon dioxide during xylose fermentation by engineered Saccharomyces cerevisiae

Author
item XIA, PENG-FEI - Shandong University
item ZHANG, GUI-CHANG - University Of Illinois
item Walker, Berkley
item SEO, SEUNG-OH - University Of Illinois
item KWAK, SURYANG - University Of Illinois
item LIU, JING-JING - University Of Illinois
item KIM, HEEJIN - University Of Illinois
item Ort, Donald
item WANG, SHU-GUANG - Shandong University
item JIN, YONG-SU - University Of Illinois

Submitted to: ACS Synthetic Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2016
Publication Date: 10/20/2016
Citation: Xia, P., Zhang, G., Walker, B.J., Seo, S., Kwak, S., Liu, J., Kim, H., Ort, D.R., Wang, S., Jin, Y. 2016. Recycling carbon dioxide during xylose fermentation by engineered Saccharomyces cerevisiae. ACS Synthetic Biology. 6(2):276-283.

Interpretive Summary: Global climate change caused by the emission of anthropogenic greenhouse gasses (GHGs) is a grand challenge to humanity. To alleviate the trend, the consumption of fossil fuels needs to be largely reduced and alternative energy technologies capable of controlling the GHG emission are anticipated. In this study, we introduced a synthetic reductive pentose phosphate pathway (rPPP) into a xylose-fermenting Saccharomyces cerevisiae strain (SR8) to achieve simultaneous lignocellulosic bioethanol production and carbon dioxide recycling. Specifically, ribulose-1,5-bisphosphate carboxylase/oxygenase from Rhodospirillum rubrum and phosphoribulokinase from Spinacia oleracea were introduced into the SR8 strain. The resulting strain with the synthetic rPPP was able to exhibit a higher yield of ethanol and lower yields of byproducts (xylitol and glycerol) than a control strain. In addition, the reduced release of carbon dioxide by the engineered strain was observed during xylose fermentation, suggesting that the carbon dioxide generated by pyruvate decarboxylase was partially re-assimilated through the synthetic rPPP. These results demonstrated that the recycling of carbon dioxide from the ethanol fermentation pathway in yeast can be achieved during lignocellulosic bioethanol production through a synthetic carbon conservative metabolic pathway. This strategy has a great potential to alleviate GHG emission during the production of the second-generation ethanol.

Technical Abstract: In this study, we introduced the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and phosphoribulokinase (PRK) into an engineered S. cerevisiae (SR8) harboring the XR/XDH pathway and up-regulated PPP 10, to enable CO2 recycling through a synthetic rPPP during xylose fermentation (Fig. 1). As the XR/XDH pathway generate surplus NADH during xylose fermentation under anaerobic conditions 26, the synthetic rPPP can exploit the surplus NADH for recycling CO2. In addition, the robust PPP of the SR8 strain offers substrates to initiate the synthetic pathway. The feasibility of this strategy was demonstrated in this study. To our knowledge, it is the first study investigated and achieved CO2 recycling during lignocellulosic bioethanol production.