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Hydrolysis pattern analysis of xylem tissues of woody plants pretreated with hydrogen peroxide and acetic acid: Rapid saccharification of softwood for economical bioconversion
Hyeun-Jong Bae
Bioenergy Research Center in Chonnam National University
Corresponding Author
ORCiD: https://orcid.org/0000-0003-3184-3425
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: Woody plants with high glucose content are alternative bioresources for the production of biofuels and biochemicals. Various pretreatment methods may be used to reduce the effects of retardation factors such as lignin interference and cellulose structural recalcitrance on the degradation of the lignocellulose material of woody plants.
Results: A hydrogen peroxide-acetic acid (HPAC) pretreatment was used to reduce the lignin content of several types of woody plants, and the effect of the cellulose structural recalcitrance on the enzymatic hydrolysis was analyzed. The cellulose structural recalcitrance and the degradation patterns of the wood fibers in the xylem tissues of Quercus acutissima (hardwood) resulted in greater retardation in the enzymatic saccharification than those in the tracheids of Pinus densiflora (softwood). In addition to the HPAC pretreatment, the application of supplementary enzymes (7.5 FPU cellulase for 24 h) further increased the hydrolysis rate of P. densiflora from 61.42% to 91.94% whereas the same effect was not observed for Q. acutissima. It was also observed that endoxylanase synergism significantly affected the hydrolysis of P. densiflora. However, this synergistic effect was lower for other supplementary enzymes. The maximum concentration of the reducing sugars produced from 10% softwood was 89.17 g L-1 after 36 h of hydrolysis with 15 FPU cellulase and other supplementary enzymes. Approximately 80 mg mL-1 of reducing sugars was produced with the addition of 7.5 FPU cellulase and other supplementary enzymes after 36 hours, achieving rapid saccharification.
Conclusion: HPAC pretreatment removed the interference of lignin, reduced structural recalcitrance of cellulose in the P. densiflora, and enabled rapid saccharification of the woody plants including a high concentration of insoluble substrates with only low amounts of cellulase. HPAC pretreatment may be a viable alternative for the cost-efficient production of biofuels or biochemicals from softwood plant tissues.
Keywords
Woody plant, pretreatment, xylem tissues, enzymatic hydrolysis, cellulose recalcitrance
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- additinalfile1figS1.jpg
Additional file 1: Figure S1. The fragmentations of HPAC-pretreated softwood and hardwood. (A) P. densiflora; (B) Q. acutissima. Tracheids or wood fibers from P. densiflora and Q. acutissima were hydrolyzed with 7.5 FPU cellulase (50 μL mL-1) g biomass-1 in 1 mL of 0.1 M citrate buffer (pH 5.0) at 50 °C. a, 0 h; b, 3 h; c, 6 h.
- additinalfile2figS2.jpg
Additional file 2: Figure S2. The comparison of end-product inhibition effect on various substrate concentrations of P. densiflora during enzymatic hydrolysis. The theoretical product of each concentration of the substrate was calculated from the concentration of reducing sugars when the hydrolysis of 1% HPAC-pretreated softwood was nearly complete. The reactions were performed with 15 FPU cellulase g biomass-1 at 50 °C for 36 h.
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On 04 Jan, 2021
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On 29 Dec, 2020
Submission checks complete
On 29 Dec, 2020
Editor invited
On 29 Dec, 2020
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Received 29 Nov, 2020
Editorial decision: Major revision
On 29 Nov, 2020
Reviewer #3 agreed
On 15 Nov, 2020
Review #1 received
Received 23 Sep, 2020
Reviewer #2 agreed
On 18 Sep, 2020
Reviewers invited
Invitations sent on 10 Aug, 2020
Reviewer #1 agreed
On 10 Aug, 2020
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On 07 Aug, 2020
Editor assigned
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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
Hydrolysis pattern analysis of xylem tissues of woody plants pretreated with hydrogen peroxide and acetic acid: Rapid saccharification of softwood for economical bioconversion
Hyeun-Jong Bae
Bioenergy Research Center in Chonnam National University
Corresponding Author
ORCiD: https://orcid.org/0000-0003-3184-3425
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: Under Review
Version 2
Posted 13 Jan, 2021
No community comments so far
Review #1 received
Received 06 Jan, 2021
Reviewer #2 agreed
On 04 Jan, 2021
Reviewer #1 agreed
On 04 Jan, 2021
Reviewers invited
Invitations sent on 03 Jan, 2021
Editor assigned
On 29 Dec, 2020
Submission checks complete
On 29 Dec, 2020
Editor invited
On 29 Dec, 2020
No comments provided
Review #2 received
Received 29 Nov, 2020
Editorial decision: Major revision
On 29 Nov, 2020
Reviewer #3 agreed
On 15 Nov, 2020
Review #1 received
Received 23 Sep, 2020
Reviewer #2 agreed
On 18 Sep, 2020
Reviewers invited
Invitations sent on 10 Aug, 2020
Reviewer #1 agreed
On 10 Aug, 2020
Editor invited
On 07 Aug, 2020
Editor assigned
On 07 Aug, 2020
First submitted
On 06 Aug, 2020
Submission checks complete
On 06 Aug, 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
Background: Woody plants with high glucose content are alternative bioresources for the production of biofuels and biochemicals. Various pretreatment methods may be used to reduce the effects of retardation factors such as lignin interference and cellulose structural recalcitrance on the degradation of the lignocellulose material of woody plants.
Results: A hydrogen peroxide-acetic acid (HPAC) pretreatment was used to reduce the lignin content of several types of woody plants, and the effect of the cellulose structural recalcitrance on the enzymatic hydrolysis was analyzed. The cellulose structural recalcitrance and the degradation patterns of the wood fibers in the xylem tissues of Quercus acutissima (hardwood) resulted in greater retardation in the enzymatic saccharification than those in the tracheids of Pinus densiflora (softwood). In addition to the HPAC pretreatment, the application of supplementary enzymes (7.5 FPU cellulase for 24 h) further increased the hydrolysis rate of P. densiflora from 61.42% to 91.94% whereas the same effect was not observed for Q. acutissima. It was also observed that endoxylanase synergism significantly affected the hydrolysis of P. densiflora. However, this synergistic effect was lower for other supplementary enzymes. The maximum concentration of the reducing sugars produced from 10% softwood was 89.17 g L-1 after 36 h of hydrolysis with 15 FPU cellulase and other supplementary enzymes. Approximately 80 mg mL-1 of reducing sugars was produced with the addition of 7.5 FPU cellulase and other supplementary enzymes after 36 hours, achieving rapid saccharification.
Conclusion: HPAC pretreatment removed the interference of lignin, reduced structural recalcitrance of cellulose in the P. densiflora, and enabled rapid saccharification of the woody plants including a high concentration of insoluble substrates with only low amounts of cellulase. HPAC pretreatment may be a viable alternative for the cost-efficient production of biofuels or biochemicals from softwood plant tissues.
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