Engineering and two-stage evolution of a lignocellulosic hydrolysate-tolerant Saccharomyces cerevisiae strain for anaerobic fermentation of xylose from AFEX pretreated corn stover
| Autor: | Lucas S. Parreiras, Rebecca J. Breuer, Ragothaman Avanasi Narasimhan, Alan J. Higbee, Alex La Reau, Mary Tremaine, Li Qin, Laura B. Willis, Benjamin D. Bice, Brandi L. Bonfert, Rebeca C. Pinhancos, Allison J. Balloon, Nirmal Uppugundla, Tongjun Liu, Chenlin Li, Deepti Tanjore, Irene M. Ong, Haibo Li, Edward L. Pohlmann, Jose Serate, Sydnor T. Withers, Blake A. Simmons, David B. Hodge, Michael S. Westphall, Joshua J. Coon, Bruce E. Dale, Venkatesh Balan, David H. Keating, Yaoping Zhang, Robert Landick, Audrey P. Gasch, Trey K. Sato |
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| Rok vydání: | 2014 |
| Předmět: |
Bioconversion
Applied Microbiology Fungal Physiology lcsh:Medicine Bioengineering Saccharomyces cerevisiae Microbial Genomics Lignin Zea mays Microbiology Molecular Evolution Molecular Genetics Industrial Microbiology Ammonia Microbial Physiology Genetics Fungal Genetics Anaerobiosis Biomass lcsh:Science Genome Evolution Molecular Biology Fungal Genomics Evolutionary Biology Multidisciplinary Xylose Ethanol Hydrolysis lcsh:R food and beverages Biology and Life Sciences Computational Biology Genomics Organismal Evolution Synthetic Bioengineering Biofuels Fermentation Microbial Evolution lcsh:Q Synthetic Biology Genetic Engineering Research Article Biotechnology |
| Zdroj: | PLoS ONE PLoS ONE, Vol 9, Iss 9, p e107499 (2014) |
| ISSN: | 1932-6203 |
| Popis: | The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX)-pretreated corn stover hydrolysate (ACSH). We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH. |
| Databáze: | OpenAIRE |
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