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Applied and Environmental Microbiology, April 2006, p. 2614-2620, Vol. 72, No. 4
0099-2240/06/$08.00+0     doi:10.1128/AEM.72.4.2614-2620.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Poly(3-Hydroxybutyrate) Synthesis by Recombinant Escherichia coli arcA Mutants in Microaerobiosis

Pablo I. Nikel,^1,2, M. Julia Pettinari,^1, Miguel A. Galvagno,^2,3 and Beatriz S. Méndez^1*

Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires,¹ Instituto de Investigaciones Biotecnológicas, Universidad de San Martín,² Departamento de Ingeniería Química, Facultad de Ingeniería, Universidad de Buenos Aires, Buenos Aires, Argentina³

Received 13 December 2005/ Accepted 2 February 2006

We assessed the effects of different arcA mutations on poly(3-hydroxybutyrate) (PHB) synthesis in recombinant Escherichia coli strains carrying the pha synthesis genes from Azotobacter sp. strain FA8. The arcA mutations used were an internal deletion and the arcA2 allele, a leaky mutation for some of the characteristics of the Arc phenotype which confers high respiratory capacity. PHB synthesis was not detected in the wild-type strain in shaken flask cultures under low-oxygen conditions, while ArcA mutants gave rise to polymer accumulation of up to 24% of their cell dry weight. When grown under microaerobic conditions in a bioreactor, the arcA deletion mutant reached a PHB content of 27% ± 2%. Under the same conditions, higher biomass and PHB concentrations were observed for the strain bearing the arcA2 allele, resulting in a PHB content of 35% ± 3%. This strain grew in a simple medium at a specific growth rate of 0.69 ± 0.07 h^–1, whereas the deletion mutant needed several nutritional additives and showed a specific growth rate of 0.56 ± 0.06 h^–1. The results presented here suggest that arcA mutations could play a role in heterologous PHB synthesis in microaerobiosis.

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* Corresponding author. Mailing address: Departamento de Química Biológica. Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria-Pabellón 2, 1428 Buenos Aires, Argentina. Phone: 54-11-4576-3334. Fax: 54-11-4576-3342. E-mail: bea{at}qb.fcen.uba.ar.

P.I.N. and M.J.P. contributed equally to this work.

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Applied and Environmental Microbiology, April 2006, p. 2614-2620, Vol. 72, No. 4
0099-2240/06/$08.00+0     doi:10.1128/AEM.72.4.2614-2620.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Nikel, P. I., Zhu, J., San, K.-Y., Mendez, B. S., Bennett, G. N. (2009). Metabolic Flux Analysis of Escherichia coli creB and arcA Mutants Reveals Shared Control of Carbon Catabolism under Microaerobic Growth Conditions. J. Bacteriol. 191: 5538-5548 [Abstract] [Full Text]  
• Nikel, P. I., de Almeida, A., Pettinari, M. J., Mendez, B. S. (2008). The Legacy of HfrH: Mutations in the Two-Component System CreBC Are Responsible for the Unusual Phenotype of an Escherichia coli arcA Mutant. J. Bacteriol. 190: 3404-3407 [Abstract] [Full Text]