Lactate production yield from engineered yeasts is dependent from the host background, the lactate dehydrogenase source and the lactate export

Branduardi Paola, Michael Sauer, De, Zampella Giuseppe, Valli Minoska, Mattanovich Diethard, Porro, Porro Danilo

Description

Metabolic pathway manipulation for improving the properties and the productivity of microorganisms is becoming a well established concept. For the production of important metabolites, but also for a better understanding of the fundamentals of cell biology, detailed studies are required. In this work we analysed the lactate production from metabolic engineered Saccharomyces cerevisiae cells expressing a heterologous lactate dehydrogenase ( LDH ) gene. The LDH gene expression in a budding yeast cell introduces a novel and alternative pathway for the NAD + regeneration, allowing a direct reduction of the intracellular pyruvate to lactate, leading to a simultaneous accumulation of lactate and ethanol. Results Four different S. cerevisiae strains were transformed with six different wild type and one mutagenised LDH genes, in combination or not with the over-expression of a lactate transporter. The resulting yield values (grams of lactate produced per grams of glucose consumed) varied from as low as 0,0008 to as high as 0.52 g g -1 . In this respect, and to the best of our knowledge, higher redirections of the glycolysis flux have never been obtained before without any disruption and/or limitation of the competing biochemical pathways. Conclusion In the present work it is shown that the redirection of the pathway towards the lactate production can be strongly modulated by the genetic background of the host cell, by the source of the heterologous Ldh enzyme, by improving its biochemical properties as well as by modulating the export of lactate in the culture media.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2006
• Nombre de lectures: 5
• Langue: English

Extrait

Microbial Cell Factories

BioMedCentral

Open Access Research Lactate production yield from engineered yeasts is dependent from the host background, the lactate dehydrogenase source and the lactate export 1 2,31 1 Paola Branduardi, Michael Sauer, Luca De Gioia, Giuseppe Zampella, 2,3 2,31 Minoska Valli, Diethard Mattanovichand Danilo Porro*

1 Address: Universitàdegli Studi di Milano – Bicocca, Dipartimento di Biotecnologie e Bioscienze, P.zza della Scienza 2, 20126 Milano, Italy, 2 Institute of Applied Microbiology, BOKU – University of Natural Resources and Applied Life Sciences, Muthgasse 18, A1190 Wien, Austria and 3 Fhcampus wien – University of Applied Sciences, School of Bioengineering, Muthgasse 18, A1190 Wien, Austria

Email: Paola Branduardi  [e-mail]; Michael Sauer  michael.sauer@fhcampuswien.ac.at; Luca De Gioia  [e-mail]; Giuseppe Zampella  [e-mail]; Minoska Valli  [e-mail]; Diethard Mattanovich  [e-mail]; Danilo Porro*  [e-mail] * Corresponding author

Published: 30 January 2006Received: 28 November 2005 Accepted: 30 January 2006 Microbial Cell Factories2006,5:4 doi:10.1186/1475-2859-5-4 This article is available from: http://www.microbialcellfactories.com/content/5/1/4 © 2006 Branduardi et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Metabolic pathway manipulation for improving the properties and the productivity of microorganisms is becoming a well established concept. For the production of important metabolites, but also for a better understanding of the fundamentals of cell biology, detailed studies are required. In this work we analysed the lactate production from metabolic engineered Saccharomyces cerevisiaecells expressing a heterologous lactate dehydrogenase (LDH) gene. The LDHgene expression in a budding yeast cell introduces a novel and alternative pathway for the + NAD regeneration,allowing a direct reduction of the intracellular pyruvate to lactate, leading to a simultaneous accumulation of lactate and ethanol.

Results:Four differentS. cerevisiaestrains were transformed with six different wild type and one mutagenisedLDHgenes, in combination or not with the over-expression of a lactate transporter. The resulting yield values (grams of lactate produced per grams of glucose consumed) varied from -1 as low as 0,0008 to as high as 0.52 g g. In this respect, and to the best of our knowledge, higher redirections of the glycolysis flux have never been obtained before without any disruption and/or limitation of the competing biochemical pathways.

Conclusion:In the present work it is shown that the redirection of the pathway towards the lactate production can be strongly modulated by the genetic background of the host cell, by the source of the heterologous Ldh enzyme, by improving its biochemical properties as well as by modulating the export of lactate in the culture media.

Background Metabolic engineering can be defined as the directed improvement of product formation or cellular properties

through the modification of specific biochemical reac tions or introduction of new ones with the use of recom binant DNA technology. Aimed to produce single

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