title: Effects of heterologous expression of phosphoenolpyruvate carboxykinase and phosphoenolpyruvate carboxylase on organic acid production in Aspergillus carbonarius.
abstract: Aspergillus carbonarius has a potential as a cell factory for production of various organic acids. In this study, the organic acid profile of A. carbonarius was investigated under different cultivation conditions. Moreover, two heterologous genes, pepck and ppc, which encode phosphoenolpyruvate carboxykinase in Actinobacillus succinogenes and phosphoenolpyruvate carboxylase in Escherichia coli, were inserted individually and in combination in A. carbonarius to enhance the carbon flux toward the reductive TCA branch. Results of transcription analysis and measurement of enzyme activities of phosphoenolpyruvate carboxykinase and phosphoenolpyruvate carboxylase in the corresponding single and double transformants demonstrated that the two heterologous genes were successfully expressed in A. carbonarius. The production of citric acid increased in all the transformants in both glucose- and xylose-based media at pH higher than 3 but did not increase in the pH non-buffered cultivation compared with the wild type.
authors.affiliation: Section for Sustainable Biotechnology, Department of Chemistry and Bioscience, Aalborg University Copenhagen, A. C. Meyers Vaenge 15, 2450, Copenhagen SV, Denmark. ly@bio.aau.dk.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Section for Sustainable Biotechnology, Department of Chemistry and Bioscience, Aalborg University Copenhagen, A. C. Meyers Vaenge 15, 2450, Copenhagen SV, Denmark. mel@bio.aau.dk.
authors.forename: Mette
authors.initials: M
authors.lastname: Lübeck
authors.affiliation: Section for Sustainable Biotechnology, Department of Chemistry and Bioscience, Aalborg University Copenhagen, A. C. Meyers Vaenge 15, 2450, Copenhagen SV, Denmark. psl@bio.aau.dk.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Lübeck
mesh_terms: D000188:Actinobacillus / Q000201:enzymology* / Q000235:genetics; D001230:Aspergillus / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D019149:Bioreactors; D057486:Carbon Cycle; D019343:Citric Acid / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000235:genetics / Q000378:metabolism*; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic; D014994:Xylose / Q000378:metabolism / Q000494:pharmacology
chemical_list: D019343:Citric Acid; D014994:Xylose; D010730:Phosphoenolpyruvate Carboxylase; D019764:Phosphoenolpyruvate Carboxykinase (ATP); D005947:Glucose
keywords: Aspergillus carbonarius; Citric acid; Organic acids; Phosphoenolpyruvate carboxykinase; Phosphoenolpyruvate carboxylase