Increasing oxygen availability for improving poly(3-hydroxybutyrate) production by Halomonas.
Metab Eng
; 45: 20-31, 2018 01.
Article
em En
| MEDLINE
| ID: mdl-29155061
ABSTRACT
Technologies enabling high-cell-density growth are required for economical industrial production of most biotechnological products. However, the key factor limiting cell density in bioreactors is the availability of oxygen during the late phases of fermentation. Although the expression of bacterial Vitreoscilla hemoglobin (VHb) is useful for enhanced oxygen availability, bacterial cell membrane makes efficient hemoglobin-oxygen contact a challenge. On the other hand, periplasmic spaces of Gram-negative microorganisms offer an excellent compartment for the intermittent storage of hemoglobin-bound oxygen. In this study, the cell growth was increased by a remarkable 100% using the twin-arginine translocase (Tat) pathway to export active VHb into the periplasm of Escherichia coli, Halomonas bluephagenesis TD01 and H. campaniensis LS21. Furthermore, eight low-oxygen-inducible vgb promoters were constructed in tandem to become a strong promoter cassette termed P8vgb, which better induces expression of both gene vgb encoding VHb and the PHB synthesis operon microaerobically. Both the P8vgb and VHb performed excellently in E. coli and two Halomonas spp., demonstrating their universal applicability for various organisms.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxigênio
/
Consumo de Oxigênio
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Poliésteres
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Proteínas de Bactérias
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Halomonas
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Hemoglobinas Truncadas
/
Hidroxibutiratos
Idioma:
En
Revista:
Metab Eng
Assunto da revista:
ENGENHARIA BIOMEDICA
/
METABOLISMO
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
China