Effect and optimization of NaOH combined with Fenton pretreatment conditions on enzymatic hydrolysis of poplar sawdust

Abstract In this study, the effects and mechanism of pretreatments of three types of chemical reagents combined with Fenton on poplar sawdust were studied and the optimization of enzymatic hydrolysis conditions was conducted using response surface methodology. The results showed that cellulase and hemicellulase had the best hydrolysis effect after NaOH-Fenton pretreatment, which were 63.73% and 29.29%, respectively. The optimal process of poplar substrate was to react in 1% NaOH at 100 ℃ for 1 h, then placed in the Fenton reaction system of 0.2 mmol Fe2+ and 25 mmol H2O2 for 7 h, and finally subjected to enzymatic hydrolysis for 72 h at 52 ℃, with a liquid-solid ratio of 33 and 15 μL/g of β-glycosidase. Under this condition, the enzymatic hydrolysis rates of cellulase and hemicellulase reached 86.65% and 43.9%, respectively. In conclusion, the combination of NaOH and Fenton pretreatment can effectively promote the enzymatic hydrolysis of poplar sawdust, which has great potential in the production of cellulosic ethanol.

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Optimization of steam pretreatment conditions for enzymatic hydrolysis of poplar wood

Holzforschung ◽

10.1515/hf.2011.066 ◽

2011 ◽

Vol 65 (4) ◽

Cited By ~ 21

Author(s):

Fokko Schütt ◽

Jürgen Puls ◽

Bodo Saake

Keyword(s):

Enzymatic Hydrolysis ◽

Raw Material ◽

Steam Pretreatment ◽

Alkaline Extraction ◽

Poplar Wood ◽

Steam Refining ◽

Severity Factor ◽

Short Rotation ◽

Pretreatment Conditions ◽

Hydrolysis Of

Abstract Steam refining was investigated as a pretreatment for enzymatic hydrolysis of poplar wood from a short rotation plantation. The experiments were carried out without debarking to use an economically realistic raw material. Steam refining conditions were varied in the range of 3–30 min and 170–220°C, according to a factorial design created with the software JMP from SAS Institute Inc., Cary, NC, USA. Predicted steaming conditions for highest glucose and xylose yields after enzymatic hydrolysis were at 210°C and 15 min. Control tests under the optimized conditions verified the predicted results. Further pretreatments without bark showed that the enzymes were not significantly inhibited by the bark. The yield of glucose and xylose was 61.9% of theoretical for the experiments with the whole raw material, whereas the yield for the experiments without bark was 63.6%. Alkaline extraction of lignin from the fibers before enzymatic hydrolysis resulted in an increase of glucose yields from mild pretreated fibers and a decrease for severe pretreated fibers. The extracted lignin had a high content of xylose of up to 14% after very mild pretreatments. On the other hand, molecular weights of the extracted lignin increased substantially after pretreatments with a severity factor above 4. Hence, alkaline extraction of the lignin seems only attractive in a narrow range of steaming conditions.

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Steam Explosion Pretreatment of Beechwood. Part 1: Comparison of the Enzymatic Hydrolysis of Washed Solids and Whole Pretreatment Slurry at Different Solid Loadings

Energies ◽

10.3390/en13143653 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3653 ◽

Cited By ~ 1

Author(s):

Robert Balan ◽

Andrzej Antczak ◽

Simone Brethauer ◽

Tomasz Zielenkiewicz ◽

Michael H. Studer

Keyword(s):

Enzymatic Hydrolysis ◽

Lignocellulosic Biomass ◽

Steam Explosion ◽

Optimization Procedure ◽

Reaction Conditions ◽

Steam Explosion Pretreatment ◽

Pretreatment Temperature ◽

Pretreatment Conditions ◽

Whole Slurry ◽

Hydrolysis Of

Steam explosion is a well-known process to pretreat lignocellulosic biomass in order to enhance sugar yields in enzymatic hydrolysis, but pretreatment conditions have to be optimized individually for each material. In this study, we investigated how the results of a pretreatment optimization procedure are influenced by the chosen reaction conditions in the enzymatic hydrolysis. Beechwood was pretreated by steam explosion and the resulting biomass was subjected to enzymatic hydrolysis at glucan loadings of 1% and 5% employing either washed solids or the whole pretreatment slurry. For enzymatic hydrolysis in both reaction modes at a glucan loading of 1%, the glucose yields markedly increased with increasing severity and with increasing pretreatment temperature at identical severities and maximal values were reached at a pretreatment temperature of 230 °C. However, the optimal severity was 5.0 for washed solids enzymatic hydrolysis, but only 4.75 for whole slurry enzymatic hydrolysis. When the glucan loading was increased to 5%, glucose yields hardly increased for pretreatment temperatures between 210 and 230 °C at a given severity, and a pretreatment temperature of 220 °C was sufficient under these conditions. Consequently, it is important to precisely choose the desired conditions of the enzymatic hydrolysis reaction, when aiming to optimize the pretreatment conditions for a certain biomass.

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Optimizing thermomechanical pretreatment conditions to enhance enzymatic hydrolysis of wheat straw by response surface methodology

Biomass and Bioenergy ◽

10.1016/j.biombioe.2011.04.012 ◽

2011 ◽

Vol 35 (7) ◽

pp. 3129-3138 ◽

Cited By ~ 22

Author(s):

Z. Maache-Rezzoug ◽

G. Pierre ◽

A. Nouviaire ◽

T. Maugard ◽

S.A. Rezzoug

Keyword(s):

Response Surface Methodology ◽

Enzymatic Hydrolysis ◽

Wheat Straw ◽

Response Surface ◽

Pretreatment Conditions ◽

Hydrolysis Of

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Co-production of Xylooligosaccharides and Xylose From Poplar Sawdust by Recombinant Endo-1,4-β-Xylanase and β-Xylosidase Mixture Hydrolysis

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2020.637397 ◽

2021 ◽

Vol 8 ◽

Author(s):

Qi Li ◽

Yunpeng Jiang ◽

Xinyi Tong ◽

Linguo Zhao ◽

Jianjun Pei

Keyword(s):

Enzymatic Hydrolysis ◽

Deep Understanding ◽

Important Application ◽

Raw Material ◽

Hydrolysis Yield ◽

Wood Polysaccharides ◽

Optimized Conditions ◽

Rate Limiting ◽

Hydrolysis Of ◽

Poplar Sawdust

As is well-known, endo-1,4-β-xylanase and β-xylosidase are the rate-limiting enzymes in the degradation of xylan (the major hemicellulosic component), main functions of which are cleavaging xylan to release xylooligosaccharides (XOS) and xylose that these two compounds have important application value in fuel, food, and other industries. This study focuses on enzymatic hydrolysis of poplar sawdust xylan for production of XOS and xylose by a GH11 endo-1,4-β-xylanase MxynB-8 and a GH39 β-xylosidase Xln-DT. MxynB-8 showed excellent ability to hydrolyze hemicellulose of broadleaf plants, such as poplar. Under optimized conditions (50°C, pH 6.0, dosage of 500 U/g, substrate concentration of 2 mg/mL), the final XOS yield was 85.5%, and the content of XOS2−3 reached 93.9% after 18 h. The enzymatic efficiency by MxynB-8 based on the poplar sawdust xylan in the raw material was 30.5%. Xln-DT showed excellent xylose/glucose/arabinose tolerance, which is applied as a candidate to apply in degradation of hemicellulose. In addition, the process and enzymatic mode of poplar sawdust xylan with MxynB-8 and Xln-DT were investigated. The results showed that the enzymatic hydrolysis yield of poplar sawdust xylan was improved by adding Xln-DT, and a xylose-rich hydrolysate could be obtained at high purity, with the xylose yield of 89.9%. The enzymatic hydrolysis yield was higher (32.2%) by using MxynB-8 and Xln-DT together. This study provides a deep understanding of double-enzyme synergetic enzymolysis of wood polysaccharides to valuable products.

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Sugar Production from Hybrid Poplar Sawdust: Optimization of Enzymatic Hydrolysis and Wet Explosion Pretreatment

Molecules ◽

10.3390/molecules25153396 ◽

2020 ◽

Vol 25 (15) ◽

pp. 3396 ◽

Cited By ~ 2

Author(s):

Rajib Biswas ◽

Philip J. Teller ◽

Muhammad U. Khan ◽

Birgitte K. Ahring

Keyword(s):

Enzymatic Hydrolysis ◽

Hybrid Poplar ◽

Pilot Scale ◽

Sugar Yield ◽

Wet Explosion Pretreatment ◽

Cellulose Digestibility ◽

Pretreatment Conditions ◽

Central Composite ◽

Poplar Sawdust ◽

Wet Explosion

Wet explosion pretreatment of hybrid poplar sawdust (PSD) for the production of fermentable sugar was carried out in the pilot-scale. The effects of pretreatment conditions, such as temperature (170–190 °C), oxygen dosage (0.5–7.5% of dry matter (DM), w/w), residence time (10–30 min), on cellulose and hemicellulose digestibility after enzymatic hydrolysis were ascertained with a central composite design of the experiment. Further, enzymatic hydrolysis was optimized in terms of temperature, pH, and a mixture of CTec2 and HTec2 enzymes (Novozymes). Predictive modeling showed that cellulose and hemicellulose digestibility of 75.1% and 83.1%, respectively, could be achieved with a pretreatment at 177 °C with 7.5% O2 and a retention time of 30 min. An increased cellulose digestibility of 87.1% ± 0.1 could be achieved by pretreating at 190 °C; however, the hemicellulose yield would be significantly reduced. It was evident that more severe conditions were required for maximal cellulose digestibility than that of hemicellulose digestibility and that an optimal sugar yield demanded a set of conditions, which overall resulted in the maximum sugar yield.

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Steam Explosion Pretreatment of Beechwood. Part 2: Quantification of Cellulase Inhibitors and Their Effect on Avicel Hydrolysis

Energies ◽

10.3390/en13143638 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3638

Author(s):

Simone Brethauer ◽

Andrzej Antczak ◽

Robert Balan ◽

Tomasz Zielenkiewicz ◽

Michael H. Studer

Keyword(s):

Acetic Acid ◽

Enzymatic Hydrolysis ◽

Steam Explosion ◽

Biomass Pretreatment ◽

Reaction Conditions ◽

Steam Explosion Pretreatment ◽

Wide Range ◽

Pretreatment Conditions ◽

Whole Slurry ◽

Hydrolysis Of

Biomass pretreatment is a mandatory step for the biochemical conversion of lignocellulose to chemicals. During pretreatment, soluble compounds are released into the prehydrolyzate that inhibit the enzymatic hydrolysis step. In this work, we investigated how the reaction conditions in steam explosion pretreatment of beechwood (severity: 3.0–5.25; temperature: 160–230 °C) influence the resulting amounts of different inhibitors. Furthermore, we quantified the extent of enzyme inhibition during enzymatic hydrolysis of Avicel in the presence of the prehydrolyzates. The amounts of phenolics, HMF, acetic acid and formic acid increased with increasing pretreatment severities and maximal quantities of 21.6, 8.3, 43.7 and 10.9 mg/gbeechwood, respectively, were measured at the highest severity. In contrast, the furfural concentration peaked at a temperature of 200 °C and a severity of 4.75. The presence of the prehydrolyzates in enzymatic hydrolysis of Avicel lowered the glucose yields by 5–26%. Mainly, the amount of phenolics and xylose and xylooligomers contributed to the reduced yield. As the maximal amounts of these two inhibitors can be found at different conditions, a wide range of pretreatment severities led to severely inhibiting prehydrolyzates. This study may provide guidelines when choosing optimal pretreatment conditions for whole slurry enzymatic hydrolysis.

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Effect of Microwave-Assisted Pretreatment Conditions on Hemicellulose Conversion and Enzymatic Hydrolysis of Norway Spruce

BioEnergy Research ◽

10.1007/s12155-015-9696-9 ◽

2015 ◽

Vol 9 (1) ◽

pp. 344-354 ◽

Cited By ~ 9

Author(s):

S. Kuittinen ◽

Y. Puentes Rodriguez ◽

M. Yang ◽

M. Keinänen ◽

O. Pastinen ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Norway Spruce ◽

Microwave Assisted ◽

Pretreatment Conditions ◽

Hydrolysis Of

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Components Analysis of Recycled Alkali Black Liquor Combined with Corn Straw under Ozone Pretreatment

10.21203/rs.3.rs-771775/v1 ◽

2021 ◽

Author(s):

Fei Li ◽

Xiaohong Lu ◽

Yiming Li ◽

Shuo Fang ◽

Xia Zhou ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Degradation Products ◽

Lignin Content ◽

Black Liquor ◽

Hydrolysis Rate ◽

Corn Straw ◽

Pretreatment Conditions ◽

Total Dissolved Solid ◽

Hydrolysis Of ◽

Cellulase Hydrolysis

Abstract Previous studies showed that the cellulase hydrolysis of corn straw pretreated with circulating alkali black liquor combined with ozone was suppressed. In this paper, the alkali black liquor was sequentially withdrawn for 0–6 times under the optimal pretreatment conditions, and components characterization was analyzed to identify the main factors inhibiting cellulase hydrolysis in recycled alkali black liquor. Through the component analysis, the organic matter and acid precipitation contents increased throughout the cycles. At the fourth cycle, the cellulase hydrolysis rate was decreased significantly, the growth of lignin content in alkali black liquor was slowed down and the total dissolved solid increment was decreased to 8.33mg/mL, 69.52% lower than previous cycle increase. GC-MS results showed that phenols, benzene ring heterocyclic and furans were main degradation products. It indicated that small molecular organics and lignin were inhibitors of cellulase hydrolysis, which accumulated during recycling, reducing alkali utilization and delignification efficiency, resulting in lower enzymatic hydrolysis rate. This study has revealed the components inhibiting the enzymatic hydrolysis of corn straw in recycled alkali black liquor, which is beneficial to the recovery and efficient utilization of recycled alkali black liquor.

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Effects of different pretreatment methods on the enzymatic hydrolysis of cassava residue

BioResources ◽

10.15376/biores.14.3.6060-6078 ◽

2019 ◽

Vol 14 (3) ◽

pp. 6060-6078

Author(s):

Zhixin Jia ◽

Ying Zheng ◽

Jinghong Zhou

Keyword(s):

Enzymatic Hydrolysis ◽

Hot Water ◽

X Ray Diffraction ◽

Alkaline Hydrogen Peroxide ◽

Glucose Yield ◽

X Ray ◽

Pretreatment Conditions ◽

Cassava Residue ◽

Hydrolysis Of ◽

Cellulase Hydrolysis

The enzymatic hydrolysis of cassava residue treated by a hot water (HW) pretreatment, an extreme-low acid (ELA) pretreatment, and an alkaline hydrogen peroxide (AHP) pretreatment was investigated. The results showed that the ELA pretreatment dissolved greater xylan and glucose quantities than the HW pretreatment under the same conditions, and the xylan and glucan contents of the pretreated substrate affected the subsequent cellulase hydrolysis. The conversion to glucose by cellulase hydrolysis reached 81.4% after the HW pretreatment, while the glucose yields under the ELA and AHP pretreatment conditions were 78.3% and 71.0%, respectively. In addition, supplementation with xylanase improved cellulase efficiency. At an equal xylanase dosage, a higher glucose yield (i.e., 91.3%) was achieved for the ELA-pretreated substrates that contained a lower xylan content. Xylanase supplementation in the AHP pretreatment had little effect on the glucose conversion. Finally, X-ray diffraction studies showed that the HW and ELA pretreatments increased the cassava residue crystallinity, while the AHP pretreatment had little effect.

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