Research

Heterologous ectoine production in Escherichia coli: By-passing the metabolic bottle-neck

Thorsten Bestvater¹, Petra Louis² and Erwin A Galinski^3*

• * Corresponding author: Erwin A Galinski galinski@uni-bonn.de

Author Affiliations

¹ Institute of Biochemistry, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 2, 48149 Münster, Germany

² Rowett Institute of Nutrition and Health, University of Aberdeen, Greeburn Road, Bucksburn, Aberdeen AB21 9SB, UK

³ Institute of Microbiology & Biotechnology, Meckenheimer Allee 168, Rheinische Friedrich-Wilhelms-Universität, 53115 Bonn, Germany

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Saline Systems 2008, 4:12 doi:10.1186/1746-1448-4-12

Published: 29 August 2008

Abstract

Transcription of the ectoine biosynthesis genes ectA, ectB and ectC from Marinococcus halophilus in recombinant Escherichia coli DH5α is probably initiated from three individual σ⁷⁰/σ^A-dependent promoter sequences, upstream of each gene. Consequently, mRNA-fragments containing the single genes and combinations of the genes ectA and ectB or ectB and ectC, respectively, could be detected by Northern blot analysis. Under the control of its own regulatory promoter region (ectUp) a seemingly osmoregulated ectoine production was observed. In addition, aspartate kinases were identified as the main limiting factor for ectoine production in recombinant E. coli DH5α. Co-expression of the ectoine biosynthesis genes and of the gene of the feedback-resistant aspartate kinase from Corynebacterium glutamicum MH20-22B (lysC) led to markedly increased production of ectoine in E. coli DH5α, resulting in cytoplasmic ectoine concentrations comparable to those reached via ectoine accumulation from the medium.