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Enhancing poly-γ-glutamic acid production in Bacillus amyloliquefaciens by introducing the glutamate synthesis features from Corynebacterium glutamicum
- Source :
- Microbial Cell Factories, Microbial Cell Factories, Vol 16, Iss 1, Pp 1-12 (2017)
- Publication Year :
- 2017
- Publisher :
- BioMed Central, 2017.
-
Abstract
- Background Poly-γ-glutamic acid (γ-PGA) is a valuable polymer with glutamate as its sole precursor. Enhancement of the intracellular glutamate synthesis is a very important strategy for the improvement of γ-PGA production, especially for those glutamate-independent γ-PGA producing strains. Corynebacterium glutamicum has long been used for industrial glutamate production and it exhibits some unique features for glutamate synthesis; therefore introduction of these metabolic characters into the γ-PGA producing strain might lead to increased intracellular glutamate availability, and thus ultimate γ-PGA production. Results In this study, the unique glutamate synthesis features from C. glutamicum was introduced into the glutamate-independent γ-PGA producing Bacillus amyloliquefaciens NK-1 strain. After introducing the energy-saving NADPH-dependent glutamate dehydrogenase (NADPH-GDH) pathway, the NK-1 (pHT315-gdh) strain showed slightly increase (by 9.1%) in γ-PGA production. Moreover, an optimized metabolic toggle switch for controlling the expression of ɑ-oxoglutarate dehydrogenase complex (ODHC) was introduced into the NK-1 strain, because it was previously shown that the ODHC in C. glutamicum was completely inhibited when glutamate was actively produced. The obtained NK-PO1 (pHT01-xylR) strain showed 66.2% higher γ-PGA production than the NK-1 strain. However, the further combination of these two strategies (introducing both NADPH-GDH pathway and the metabolic toggle switch) did not lead to further increase of γ-PGA production but rather the resultant γ-PGA production was even lower than that in the NK-1 strain. Conclusions We proposed new metabolic engineering strategies to improve the γ-PGA production in B. amyloliquefaciens. The NK-1 (pHT315-gdh) strain with the introduction of NADPH-GDH pathway showed 9.1% improvement in γ-PGA production. The NK-PO1 (pHT01-xylR) strain with the introduction of a metabolic toggle switch for controlling the expression of ODHC showed 66.2% higher γ-PGA production than the NK-1 strain. This work proposed a new strategy for improving the target product in microbial cell factories. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0704-y) contains supplementary material, which is available to authorized users.
- Subjects :
- 0301 basic medicine
Bacillus amyloliquefaciens
lcsh:QR1-502
Glutamic Acid
Bioengineering
Applied Microbiology and Biotechnology
lcsh:Microbiology
Corynebacterium glutamicum
Metabolic engineering
03 medical and health sciences
Industrial Microbiology
Glutamate Dehydrogenase (NADP+)
biology
Strain (chemistry)
Poly-γ-glutamic acid
Glutamate dehydrogenase
Research
Metabolic toggle switch
Glutamate receptor
Glutamic acid
biology.organism_classification
030104 developmental biology
Biochemistry
NADPH-dependent glutamate dehydrogenase
Metabolic Engineering
Polyglutamic Acid
Fermentation
Gene Deletion
Metabolic Networks and Pathways
NADP
Biotechnology
Sugar Alcohol Dehydrogenases
Subjects
Details
- Language :
- English
- ISSN :
- 14752859
- Volume :
- 16
- Database :
- OpenAIRE
- Journal :
- Microbial Cell Factories
- Accession number :
- edsair.doi.dedup.....c604ed601cdb1673133cfb7486e514f9