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Microbial synthesis of poly- γ -glutamic acid ( γ -PGA) with fulvic acid powder, the waste from yeast molasses fermentation
Gaofu Qi
Huazhong Agriculture University
Corresponding Author
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Biotechnology for Biofuels.
Background: Molasses is a wildly used feedstock for fermentation, but it also poses a severe wastewater-disposal problem worldwide. Recently, the wastewater from yeast molasses fermentation is being processed into fulvic acid (FA) powder as a fertilizer for crops, but it consequently induces a problem of soil acidification after being directly applied into soil. In this study, the low-cost FA powder was bioconverted into a value-added product of γ-PGA by a glutamate independent producer of Bacillus velezensis GJ11.
Results: FA power could partially substitute the high-cost substrates such as sodium glutamate and citrate sodium for producing γ-PGA. With FA powder in the fermentation medium, the amount of sodium glutamate and citrate sodium used for producing γ-PGA were both decreased around one third. Moreover, FA powder could completely substitute Mg2+, Mn2+, Ca2+ and Fe3+ in the fermentation medium for producing γ-PGA. In the optimized medium with FA powder, the γ-PGA was produced at 42.55 g/L with a productivity of 1.15 g/(L·h), while only 2.87 g/L was produced in the medium without FA powder. Hydrolyzed γ-PGA could trigger induced systemic resistance (ISR), e.g. H2O2 accumulation and callose deposition, against the pathogen’s infection in plants. Further investigations found the ISR triggered by γ-PGA hydrolysates was dependent on the ethylene (ET) signalling and nonexpressor of pathogenesis-related proteins 1 (NPR1).
Conclusions: To our knowledge, this is the first report to use the industry waste, FA powder, as a sustainable substrate for microbial synthesis of γ-PGA. This bioprocess can not only develop a new way to use FA powder as a cheap feedstock for producing γ-PGA, but also help to reduce pollution from the wastewater of yeast molasses fermentation.
Keywords
Molasses, Fulvic acid powder, Poly-γ-glutamic acid (γ-PGA), Bacillus velezensis, Induced systemic resistance (ISR), Ethylene (ET) signalling
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CURRENT STATUS: Published
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Posted 24 Sep, 2020
Published
On 28 Oct, 2020
No community comments so far
Editorial decision: Accept
On 10 Oct, 2020
Review #2 received
Received 09 Oct, 2020
Reviewer #2 agreed
On 29 Sep, 2020
Review #1 received
Received 29 Sep, 2020
Reviewer #1 agreed
On 28 Sep, 2020
Reviewers invited
Invitations sent on 27 Sep, 2020
Editor assigned
On 24 Sep, 2020
Submission checks complete
On 23 Sep, 2020
Editor invited
On 23 Sep, 2020
No comments provided
Editorial decision: Major revision
On 01 Sep, 2020
Review #2 received
Received 21 Aug, 2020
Review #3 received
Received 21 Aug, 2020
Review #1 received
Received 21 Aug, 2020
Reviewer #3 agreed
On 10 Aug, 2020
Reviewer #2 agreed
On 08 Aug, 2020
Reviewer #1 agreed
On 07 Aug, 2020
Reviewers invited
Invitations sent on 06 Aug, 2020
Editor assigned
On 25 Jul, 2020
First submitted
On 24 Jul, 2020
Submission checks complete
On 24 Jul, 2020
Editor invited
On 24 Jul, 2020
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Subject Areas
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This preprint is under consideration at Biotechnology for Biofuels. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Microbial synthesis of poly- γ -glutamic acid ( γ -PGA) with fulvic acid powder, the waste from yeast molasses fermentation
Gaofu Qi
Huazhong Agriculture University
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
Version 2
Posted 24 Sep, 2020
Published
On 28 Oct, 2020
No community comments so far
Editorial decision: Accept
On 10 Oct, 2020
Review #2 received
Received 09 Oct, 2020
Reviewer #2 agreed
On 29 Sep, 2020
Review #1 received
Received 29 Sep, 2020
Reviewer #1 agreed
On 28 Sep, 2020
Reviewers invited
Invitations sent on 27 Sep, 2020
Editor assigned
On 24 Sep, 2020
Submission checks complete
On 23 Sep, 2020
Editor invited
On 23 Sep, 2020
No comments provided
Editorial decision: Major revision
On 01 Sep, 2020
Review #2 received
Received 21 Aug, 2020
Review #3 received
Received 21 Aug, 2020
Review #1 received
Received 21 Aug, 2020
Reviewer #3 agreed
On 10 Aug, 2020
Reviewer #2 agreed
On 08 Aug, 2020
Reviewer #1 agreed
On 07 Aug, 2020
Reviewers invited
Invitations sent on 06 Aug, 2020
Editor assigned
On 25 Jul, 2020
First submitted
On 24 Jul, 2020
Submission checks complete
On 24 Jul, 2020
Editor invited
On 24 Jul, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Biotechnology and Bioengineering
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Biotechnology for Biofuels.
Background: Molasses is a wildly used feedstock for fermentation, but it also poses a severe wastewater-disposal problem worldwide. Recently, the wastewater from yeast molasses fermentation is being processed into fulvic acid (FA) powder as a fertilizer for crops, but it consequently induces a problem of soil acidification after being directly applied into soil. In this study, the low-cost FA powder was bioconverted into a value-added product of γ-PGA by a glutamate independent producer of Bacillus velezensis GJ11.
Results: FA power could partially substitute the high-cost substrates such as sodium glutamate and citrate sodium for producing γ-PGA. With FA powder in the fermentation medium, the amount of sodium glutamate and citrate sodium used for producing γ-PGA were both decreased around one third. Moreover, FA powder could completely substitute Mg2+, Mn2+, Ca2+ and Fe3+ in the fermentation medium for producing γ-PGA. In the optimized medium with FA powder, the γ-PGA was produced at 42.55 g/L with a productivity of 1.15 g/(L·h), while only 2.87 g/L was produced in the medium without FA powder. Hydrolyzed γ-PGA could trigger induced systemic resistance (ISR), e.g. H2O2 accumulation and callose deposition, against the pathogen’s infection in plants. Further investigations found the ISR triggered by γ-PGA hydrolysates was dependent on the ethylene (ET) signalling and nonexpressor of pathogenesis-related proteins 1 (NPR1).
Conclusions: To our knowledge, this is the first report to use the industry waste, FA powder, as a sustainable substrate for microbial synthesis of γ-PGA. This bioprocess can not only develop a new way to use FA powder as a cheap feedstock for producing γ-PGA, but also help to reduce pollution from the wastewater of yeast molasses fermentation.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7