Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis
The production of poly-γ-glutamic acid (γ-PGA), a biopolymer consisting of D- and L-glutamic acid monomers, currently relies on L-glutamate, or citrate as carbon substrates. Here we aimed at using plant biomass-derived substrates such as xylose. γ-PGA producing microorganisms including Bacillus subt...
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Frontiers Media S.A.
2020-01-01
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| Series: | Frontiers in Bioengineering and Biotechnology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fbioe.2019.00476/full |
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| author | Birthe Halmschlag Kyra Hoffmann René Hanke Sastia P. Putri Eiichiro Fukusaki Jochen Büchs Lars M. Blank |
| author_facet | Birthe Halmschlag Kyra Hoffmann René Hanke Sastia P. Putri Eiichiro Fukusaki Jochen Büchs Lars M. Blank |
| author_sort | Birthe Halmschlag |
| collection | DOAJ |
| description | The production of poly-γ-glutamic acid (γ-PGA), a biopolymer consisting of D- and L-glutamic acid monomers, currently relies on L-glutamate, or citrate as carbon substrates. Here we aimed at using plant biomass-derived substrates such as xylose. γ-PGA producing microorganisms including Bacillus subtilis natively metabolize xylose via the isomerase pathway. The Weimberg pathway, a xylose utilization pathway first described for Caulobacter crescentus, offers a carbon-efficient alternative converting xylose to 2-oxoglutarate without carbon loss. We engineered a recombinant B. subtilis strain that was able to grow on xylose with a growth rate of 0.43 h−1 using a recombinant Weimberg pathway. Although ion-pair reversed-phase LC/MS/MS metabolome analysis revealed lower concentrations of γ-PGA precursors such as 2-oxoglutarate, the γ-PGA titer was increased 6-fold compared to the native xylose isomerase strain. Further metabolome analysis indicates a metabolic bottleneck in the phosphoenolpyruvate-pyruvate-oxaloacetate node causing bi-phasic (diauxic) growth of the recombinant Weimberg strain. Flux balance analysis (FBA) of the γ-PGA producing B. subtilis indicated that a maximal theoretical γ-PGA yield is achieved on D-xylose/ D-glucose mixtures. The results of the B. subtilis strain harboring the Weimberg pathway on such D-xylose/ D-glucose mixtures demonstrate indeed resource efficient, high yield γ-PGA production from biomass-derived substrates. |
| first_indexed | 2024-12-11T18:39:31Z |
| format | Article |
| id | doaj.art-09b0aa08aea34e30ae620a978b8dc059 |
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| issn | 2296-4185 |
| language | English |
| last_indexed | 2024-12-11T18:39:31Z |
| publishDate | 2020-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Bioengineering and Biotechnology |
| spelling | doaj.art-09b0aa08aea34e30ae620a978b8dc0592022-12-22T00:54:39ZengFrontiers Media S.A.Frontiers in Bioengineering and Biotechnology2296-41852020-01-01710.3389/fbioe.2019.00476503151Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilisBirthe Halmschlag0Kyra Hoffmann1René Hanke2Sastia P. Putri3Eiichiro Fukusaki4Jochen Büchs5Lars M. Blank6Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, GermanyAVT-Biochemical Engineering, RWTH Aachen University, Aachen, GermanyAVT-Biochemical Engineering, RWTH Aachen University, Aachen, GermanyDepartment of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, JapanDepartment of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, JapanAVT-Biochemical Engineering, RWTH Aachen University, Aachen, GermanyInstitute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, GermanyThe production of poly-γ-glutamic acid (γ-PGA), a biopolymer consisting of D- and L-glutamic acid monomers, currently relies on L-glutamate, or citrate as carbon substrates. Here we aimed at using plant biomass-derived substrates such as xylose. γ-PGA producing microorganisms including Bacillus subtilis natively metabolize xylose via the isomerase pathway. The Weimberg pathway, a xylose utilization pathway first described for Caulobacter crescentus, offers a carbon-efficient alternative converting xylose to 2-oxoglutarate without carbon loss. We engineered a recombinant B. subtilis strain that was able to grow on xylose with a growth rate of 0.43 h−1 using a recombinant Weimberg pathway. Although ion-pair reversed-phase LC/MS/MS metabolome analysis revealed lower concentrations of γ-PGA precursors such as 2-oxoglutarate, the γ-PGA titer was increased 6-fold compared to the native xylose isomerase strain. Further metabolome analysis indicates a metabolic bottleneck in the phosphoenolpyruvate-pyruvate-oxaloacetate node causing bi-phasic (diauxic) growth of the recombinant Weimberg strain. Flux balance analysis (FBA) of the γ-PGA producing B. subtilis indicated that a maximal theoretical γ-PGA yield is achieved on D-xylose/ D-glucose mixtures. The results of the B. subtilis strain harboring the Weimberg pathway on such D-xylose/ D-glucose mixtures demonstrate indeed resource efficient, high yield γ-PGA production from biomass-derived substrates.https://www.frontiersin.org/article/10.3389/fbioe.2019.00476/fullBacillus subtilisγ-PGAonline viscosity measurementmetabolic engineeringweimberg pathwayxylose |
| spellingShingle | Birthe Halmschlag Kyra Hoffmann René Hanke Sastia P. Putri Eiichiro Fukusaki Jochen Büchs Lars M. Blank Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis Frontiers in Bioengineering and Biotechnology Bacillus subtilis γ-PGA online viscosity measurement metabolic engineering weimberg pathway xylose |
| title | Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis |
| title_full | Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis |
| title_fullStr | Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis |
| title_full_unstemmed | Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis |
| title_short | Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis |
| title_sort | comparison of isomerase and weimberg pathway for γ pga production from xylose by engineered bacillus subtilis |
| topic | Bacillus subtilis γ-PGA online viscosity measurement metabolic engineering weimberg pathway xylose |
| url | https://www.frontiersin.org/article/10.3389/fbioe.2019.00476/full |
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