Metabolic Engineering of a Phosphoketolase Pathway for Pentose Catabolism in Saccharomyces cerevisiae
AUTOR(ES)
Sonderegger, Marco
FONTE
American Society for Microbiology
RESUMO
Low ethanol yields on xylose hamper economically viable ethanol production from hemicellulose-rich plant material with Saccharomyces cerevisiae. A major obstacle is the limited capacity of yeast for anaerobic reoxidation of NADH. Net reoxidation of NADH could potentially be achieved by channeling carbon fluxes through a recombinant phosphoketolase pathway. By heterologous expression of phosphotransacetylase and acetaldehyde dehydrogenase in combination with the native phosphoketolase, we installed a functional phosphoketolase pathway in the xylose-fermenting Saccharomyces cerevisiae strain TMB3001c. Consequently the ethanol yield was increased by 25% because less of the by-product xylitol was formed. The flux through the recombinant phosphoketolase pathway was about 30% of the optimum flux that would be required to completely eliminate xylitol and glycerol accumulation. Further overexpression of phosphoketolase, however, increased acetate accumulation and reduced the fermentation rate. By combining the phosphoketolase pathway with the ald6 mutation, which reduced acetate formation, a strain with an ethanol yield 20% higher and a xylose fermentation rate 40% higher than those of its parent was engineered.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=404438Documentos Relacionados
- Engineering Redox Cofactor Regeneration for Improved Pentose Fermentation in Saccharomyces cerevisiae
- Metabolic Engineering of Saccharomyces cerevisiae
- Metabolic Engineering of Glycerol Production in Saccharomyces cerevisiae
- Metabolic Engineering of Ammonium Assimilation in Xylose-Fermenting Saccharomyces cerevisiae Improves Ethanol Production
- Engenharia metabólica de leveduras industriais (Saccharomyces cerevisiae) para produção de glicerol