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Fang H, Xie X, Chu Q, Tong W, Song K. Modified 1,4-butanediol organosolv pretreatment on hardwoodandsoftwood for efficient coproduction of fermentable sugars and lignin antioxidants. BIORESOURCE TECHNOLOGY 2023; 376:128854. [PMID: 36898561 DOI: 10.1016/j.biortech.2023.128854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/05/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
In this work, 1,4-butanediol (BDO) organosolv pretreatment was modified with different additives for efficient coproduction of fermentable sugars and lignin antioxidants from hardwood poplar and softwood masson pine. It was found additives more greatly improved pretreatment efficacy of softwood than hardwood. 3-hydroxy-2-naphthoic acid (HNA) addition introduced hydrophilic acid groups to lignin structure, while 2-naphthol-7-sulphonate (NS) addition promoted lignin removal, both improving cellulose accessibility for enzymatic hydrolysis. Consequently, BDO pretreatment with 90 mM acid and 2-naphthol-7-sulphonate addition achieved near complete cellulose hydrolysis (97.98%) and maximized sugar yield of 88.23% from masson pine at 2% cellulose and 20 FPU/g enzyme loading. More importantly, the recovered lignin possessed great antioxidant activity (RSI = 2.48), due to increased phenolic OH groups, reduced aliphatic OH groups and molecular weight. Results indicated the modified BDO pretreatment could significantly improve enzymatic saccharification of highly-recalcitrant softwood, while enabling coproduction of high-performance lignin antioxidants for full biomass utilization.
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Affiliation(s)
- Huaxing Fang
- College of Biology and the Environment, Nanjing Forestry University, No.159 Longpan Road, Nanjing 210037, China
| | - Xinyu Xie
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Light Industry and Food Engineering, Nanjing Forestry University, No.159 Longpan Road, Nanjing 210037, China
| | - Qiulu Chu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Light Industry and Food Engineering, Nanjing Forestry University, No.159 Longpan Road, Nanjing 210037, China
| | - Wenyao Tong
- College of Biology and the Environment, Nanjing Forestry University, No.159 Longpan Road, Nanjing 210037, China
| | - Kai Song
- College of Biology and the Environment, Nanjing Forestry University, No.159 Longpan Road, Nanjing 210037, China.
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2
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Study on Soda–Ethanol Delignification of Pine Sawdust for a Biorefinery. SUSTAINABILITY 2022. [DOI: 10.3390/su14116660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
The soda–ethanol process was conceived as a sulfur-free pulping process, which may also be an alternative to conventional alkaline pulping, such as kraft or soda–AQ in the biorefinery context. An in-depth study using two experimental designs was conducted to establish the viability of soda–ethanol delignification of pine sawdust. At first, a simple factorial design involving the ethanol–water ratio (ethanol:water) and the alkaline load (AL, % over dry wood, odw) was applied to define the levels of these variables and their eventual interaction. Then, a 32 experimental design was performed to evaluate the ability of the process concerning the pulping of pine sawdust. The tested conditions were carefully selected to screen a broad range of cooking times (60, 100, and 140 min) and alkaline loads (19.0, 23.3, and 27.6 %odw) to obtain pulps with different extents of delignification (residual lignin contents). Finally, the kraft, soda–AQ, and soda–ethanol treatments were compared. Soda–ethanol pulping was shown to be a suitable delignification stage for a biorefinery scheme of Pinus elliottii and Pinus taeda sawdust. It has many advantages over traditional processes regarding its environmental impact, harmless chemicals, and selectivity. The tested conditions were similar to those frequently used in conventional pulping at an industrial scale, suggesting the technical feasibility of the soda–ethanol process for pine sawdust processing.
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3
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Wu J, Ebadian M, Kim KH, Kim CS, Saddler J. The use of steam pretreatment to enhance pellet durability and the enzyme-mediated hydrolysis of pellets to fermentable sugars. BIORESOURCE TECHNOLOGY 2022; 347:126731. [PMID: 35074465 DOI: 10.1016/j.biortech.2022.126731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/13/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Although densified wood pellets are an attractive biomass feedstock for bioenergy and biofuels production, partly due to their ease of transport, their friability and hygroscopic nature (attraction of moisture) have proven problematic in terms of storage and handling. Pre-steaming the biomass was shown to reduce the need for size reduction, significantly increasing pellet durability by relocating the plant cell wall lignin to the fibre surface and consequently enhancing binding between particles. Although steam pretreatment has been shown to facilitate enzyme-mediated hydrolysis of biomass, by increasing cellulose accessibility, drying and pelletization partially impeded enzymatic hydrolysis. However, the incorporation of alkaline deacetylation or neutral sulfonation step prior to pre-steaming was shown to mitigate many of the negative effects of drying. Although drying and pelletization did not significantly impact the redistribution of lignin, a mild mechanical refining step was shown to further enhance the hydrolysis of the cellulose component of the pelletized biomass.
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Affiliation(s)
- Jie Wu
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada
| | - Mahmood Ebadian
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada
| | - Kwang Ho Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Chang Soo Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Jack Saddler
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada.
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4
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Del Río PG, Gullón B, Wu J, Saddler J, Garrote G, Romaní A. Current breakthroughs in the hardwood biorefineries: Hydrothermal processing for the co-production of xylooligosaccharides and bioethanol. BIORESOURCE TECHNOLOGY 2022; 343:126100. [PMID: 34626760 DOI: 10.1016/j.biortech.2021.126100] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
The development of lignocellulosic biorefineries requires a first stage of pretreatment which enables the efficient valorization of all fractions present in this renewable material. In this sense, this review aims to show the main advantages of hydrothermal treatment as a first step of a biorefinery infrastructure using hardwood as raw material, as well as, main drawback to overcome. Hydrothermal treatment of hardwood highlights for its high selectivity for hemicelluloses solubilization as xylooligosaccharides (XOS). Nevertheless, the suitable conditions for XOS production are inadequate to achieve an elevate cellulose to glucose conversion. Hence, several strategies namely the combination of hydrothermal treatment with delignification process, in situ modification of lignin and the mixture with another renewable resources (concretely, seaweeds, and by-products generated in the food industry with high sugar content) were pinpointed as promising alternative to increase the final ethanol concentration coupled with XOS recovery in the hydrolysate.
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Affiliation(s)
- Pablo G Del Río
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain
| | - Beatriz Gullón
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain
| | - Jie Wu
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jack Saddler
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Gil Garrote
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain
| | - Aloia Romaní
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain.
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Yuan Y, Jiang B, Chen H, Wu W, Wu S, Jin Y, Xiao H. Recent advances in understanding the effects of lignin structural characteristics on enzymatic hydrolysis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:205. [PMID: 34670604 PMCID: PMC8527784 DOI: 10.1186/s13068-021-02054-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/10/2021] [Indexed: 05/19/2023]
Abstract
Enzymatic hydrolysis of lignocellulose for bioethanol production shows a great potential to remit the rapid consumption of fossil fuels, given the fact that lignocellulose feedstocks are abundant, cost-efficient, and renewable. Lignin results in low enzymatic saccharification by forming the steric hindrance, non-productive adsorption of cellulase onto lignin, and deactivating the cellulase. In general, the non-productive binding of cellulase on lignin is widely known as the major cause for inhibiting the enzymatic hydrolysis. Pretreatment is an effective way to remove lignin and improve the enzymatic digestibility of lignocellulose. Along with removing lignin, the pretreatment can modify the lignin structure, which significantly affects the non-productive adsorption of cellulase onto lignin. To relieve the inhibitory effect of lignin on enzymatic hydrolysis, enormous efforts have been made to elucidate the correlation of lignin structure with lignin-enzyme interactions but with different views. In addition, contrary to the traditional belief that lignin inhibits enzymatic hydrolysis, in recent years, the addition of water-soluble lignin such as lignosulfonate or low molecular-weight lignin exerts a positive effect on enzymatic hydrolysis, which gives a new insight into the lignin-enzyme interactions. For throwing light on their structure-interaction relationship during enzymatic hydrolysis, the effect of residual lignin in substrate and introduced lignin in hydrolysate on enzymatic hydrolysis are critically reviewed, aiming at realizing the targeted regulation of lignin structure for improving the saccharification of lignocellulose. The review is also focused on exploring the lignin-enzyme interactions to mitigate the negative impact of lignin and reducing the cost of enzymatic hydrolysis of lignocellulose.
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Affiliation(s)
- Yufeng Yuan
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Bo Jiang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Hui Chen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Wenjuan Wu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Shufang Wu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Yongcan Jin
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China.
- Laboratory of Wood Chemistry, Nanjing Forestry University, 159 Longpan Rd, Nanjing, 210037, China.
| | - Huining Xiao
- Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, E3B 11 5A3, Canada
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6
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Lee DS, Lee YG, Cho EJ, Song Y, Bae HJ. Hydrolysis pattern analysis of xylem tissues of woody plants pretreated with hydrogen peroxide and acetic acid: rapid saccharification of softwood for economical bioconversion. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:37. [PMID: 33549141 PMCID: PMC7866737 DOI: 10.1186/s13068-021-01889-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 01/25/2021] [Indexed: 05/20/2023]
Abstract
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 h, 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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Affiliation(s)
- Dae-Seok Lee
- Bio-Energy Research Center, Chonnam National University, Gwangju, 500-757, Republic of Korea
| | - Yoon-Gyo Lee
- Bio-Energy Research Center, Chonnam National University, Gwangju, 500-757, Republic of Korea
| | - Eun Jin Cho
- Bio-Energy Research Center, Chonnam National University, Gwangju, 500-757, Republic of Korea
| | - Younho Song
- Bio-Energy Research Center, Chonnam National University, Gwangju, 500-757, Republic of Korea
| | - Hyeun-Jong Bae
- Bio-Energy Research Center, Chonnam National University, Gwangju, 500-757, Republic of Korea.
- Department of Bioenergy Science and Technology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 500-757, Republic of Korea.
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7
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Jia Y, Yang C, Shen B, Ling Z, Huang C, Li X, Lai C, Yong Q. Comparative study on enzymatic digestibility of acid-pretreated poplar and larch based on a comprehensive analysis of the lignin-derived recalcitrance. BIORESOURCE TECHNOLOGY 2021; 319:124225. [PMID: 33254454 DOI: 10.1016/j.biortech.2020.124225] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/01/2020] [Accepted: 10/04/2020] [Indexed: 05/20/2023]
Abstract
Enzymatic digestibility of an acid-pretreated poplar (AP, 42.9%) was superior to that of a similarly acid-pretreated larch (AL, 12.5%). Effects of lignin-related recalcitrance on enzymatic hydrolysis were comprehensively investigated by disrupting the two predominant lignin fractions present in acid-pretreated material (extractable lignin and bulk lignin). Lignin removal and bovine serum albumin (BSA) addition were performed to estimate the relative contributions of lignin towards physical blocking and enzyme binding on enzymatic hydrolysis. The lignin physical blocking played a more significant role in limiting the enzymatic hydrolysis of AL. BSA addition improved enzymatic hydrolysis of AP more significantly than AL. Moreover, the effects of lignin embedded in the lignocellulosic matrix on enzyme non-productive binding were compared with the isolated lignin. It indicated that the lignin distribution would influence the lignin effects on enzyme non-productive binding during enzymatic hydrolysis. Results will give insights towards improvement of enzymatic hydrolysis on acid-pretreated woody biomass.
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Affiliation(s)
- Yuan Jia
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Chundong Yang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Buzhen Shen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Zhe Ling
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Caoxing Huang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Xin Li
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China; Key Laboratory of Forestry Genetics & Biotechnology (Nanjing Forestry University), Ministry of Education, Nanjing 210037, People's Republic of China
| | - Chenhuan Lai
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China; Key Laboratory of Forestry Genetics & Biotechnology (Nanjing Forestry University), Ministry of Education, Nanjing 210037, People's Republic of China.
| | - Qiang Yong
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China; Key Laboratory of Forestry Genetics & Biotechnology (Nanjing Forestry University), Ministry of Education, Nanjing 210037, People's Republic of China
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8
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Effect of Severity Factor on the Subcritical Water and Enzymatic Hydrolysis of Coconut Husk for Reducing Sugar Production. BULLETIN OF CHEMICAL REACTION ENGINEERING & CATALYSIS 2020. [DOI: 10.9767/bcrec.15.3.8870.786-797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Preventing the further degradation of monomeric or oligomeric sugar into by-product during biomass conversion is one of the challenges for fermentable sugar production. In this study, the performance of subcritical water (SCW) and enzymatic hydrolysis of coconut husk toward reducing sugar production was investigated using a severity factor (SF) approach. Furthermore, the optimal condition of SCW was optimized using response surface methodology (RSM), where the composition changes of lignocellulose and sugar yield as responses. From the results, at low SF of SCW, sugar yield escalated as increasing SF value. In the enzymatic hydrolysis process, the effect of SCW pressure is a significant factor enhancing sugar yield. A maximum total sugar yield was attained on the mild SF condition of 2.86. From this work, it was known that the SF approach is sufficient parameter to evaluate the SCW and enzymatic hydrolysis of coconut husk. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
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9
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Wu J, Chandra RP, Takada M, Liu LY, Renneckar S, Kim KH, Kim CS, Saddler JN. Enhancing Enzyme-Mediated Cellulose Hydrolysis by Incorporating Acid Groups Onto the Lignin During Biomass Pretreatment. Front Bioeng Biotechnol 2020; 8:608835. [PMID: 33282856 PMCID: PMC7691530 DOI: 10.3389/fbioe.2020.608835] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 10/26/2020] [Indexed: 11/13/2022] Open
Abstract
Lignin is known to limit the enzyme-mediated hydrolysis of biomass by both restricting substrate swelling and binding to the enzymes. Pretreated mechanical pulp (MP) made from Aspen wood chips was incubated with either 16% sodium sulfite or 32% sodium percarbonate to incorporate similar amounts of sulfonic and carboxylic acid groups onto the lignin (60 mmol/kg substrate) present in the pulp without resulting in significant delignification. When Simon's stain was used to assess potential enzyme accessibility to the cellulose, it was apparent that both post-treatments enhanced accessibility and cellulose hydrolysis. To further elucidate how acid group addition might influence potential enzyme binding to lignin, Protease Treated Lignin (PTL) was isolated from the original and modified mechanical pulps and added to a cellulose rich, delignified Kraft pulp. As anticipated, the PTLs from both the oxidized and sulfonated substrates proved less inhibitory and adsorbed less enzymes than did the PTL derived from the original pulp. Subsequent analyses indicated that both the sulfonated and oxidized lignin samples contained less phenolic hydroxyl groups, resulting in enhanced hydrophilicity and a more negative charge which decreased the non-productive binding of the cellulase enzymes to the lignin.
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Affiliation(s)
- Jie Wu
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada
| | - Richard P Chandra
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada
| | - Masatsugu Takada
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada.,International Advanced Energy Science Research and Education Center, Graduate School of Energy Science, Kyoto University, Kyoto, Japan
| | - Li-Yang Liu
- Advanced Renewable Materials Lab, Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada
| | - Scott Renneckar
- Advanced Renewable Materials Lab, Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada
| | - Kwang Ho Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Chang Soo Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jack N Saddler
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada
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Wu J, Chandra R, Takada M, Del Rio P, Kim KH, Kim CS, Liu LY, Renneckar S, Saddler J. Alkaline sulfonation and thermomechanical pulping pretreatment of softwood chips and pellets to enhance enzymatic hydrolysis. BIORESOURCE TECHNOLOGY 2020; 315:123789. [PMID: 32682260 DOI: 10.1016/j.biortech.2020.123789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
To assess the impact of alkalinity on sulfonation and the enzyme-mediated hydrolysis of softwood cellulose, Lodgepole pine chips were impregnated with 8% sodium sulfite and increasing loadings of sodium carbonate before thermomechanical pulping. It was apparent that alkali addition enhanced lignin sulfonation with an additional 4% loading of sodium carbonate proving optimal. TEM indicated that sulfonation predominantly occurred within the secondary-cell-wall lignin, increasing cellulose accessibility to the cellulase enzymes. Although increasing alkalinity did not significantly enhance lignin sulfonation, likely due to the lower acetyl content of the softwood chips, it increases mannan solubilization. Despite their smaller particle size, softwood pellets were more poorly sulfonated, probably due to their higher lignin content and lower amount of acid groups. This more condensed lignin structure was confirmed by 2D-NMR and GPC analyses which indicated that the EMAL derived from softwood pellets contained less native β-O-4 linkages and had a higher molecular weight.
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Affiliation(s)
- Jie Wu
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada
| | - Richard Chandra
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada
| | - Masatsugu Takada
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada; International Advanced Energy Science Research and Education Center, Graduate School of Energy Science, Kyoto University, 301, Faculty of Engineering Integrated Research Building, Yoshida-Honmachi, Kyoto 606-850, Japan
| | - Pablo Del Rio
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada; Department of Chemical Engineering, Faculty of Science, University of Vigo, As Lagoas, 32004 Ourense, Spain
| | - Kwang Ho Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seul 136-791, Republic of Korea
| | - Chang Soo Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seul 136-791, Republic of Korea
| | - Li-Yang Liu
- Advanced Renewable Materials Lab, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada
| | - Scott Renneckar
- Advanced Renewable Materials Lab, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada
| | - Jack Saddler
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada.
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Shi F, Wang Y, Davaritouchaee M, Yao Y, Kang K. Directional Structure Modification of Poplar Biomass-Inspired High Efficacy of Enzymatic Hydrolysis by Sequential Dilute Acid-Alkali Treatment. ACS OMEGA 2020; 5:24780-24789. [PMID: 33015496 PMCID: PMC7528282 DOI: 10.1021/acsomega.0c03419] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
A major challenge in converting lignocellulose to biofuel is overcoming the resistance of the biomass structure. Herein, sequential dilute acid-alkali/aqueous ammonia treatment was evaluated to enhance enzymatic hydrolysis of poplar biomass by removing hemicellulose first and then removing lignin with acid and base, respectively. The results show that glucose release in sequential dilute acid-alkali treatments (61.4-71.4 mg/g) was 7.3-24.8% higher than sequential dilute acid-aqueous ammonia treatments (57.2-61.8 mg/g) and 283.8-346.3% higher than control (16.0 mg/g), respectively. Dilute acid treatment removed most hemicellulose (84.9%) of the biomass, followed by alkaline treatment with 27.5% removal of lignin. Roughness, surface area, and micropore volume of the biomass were crucial for the enzymatic hydrolysis. Furthermore, the ultrastructure changes observed using crystallinity, Fourier transform infrared spectroscopy, thermogravimetric analysis, and pyrolysis gas chromatography/mass spectrometry support the effects of sequential dilute acid-alkali treatment. The results provide an efficient approach to facilitate a better enzymatic hydrolysis of the poplar samples.
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Affiliation(s)
- Fuxi Shi
- College
of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China
| | - Yajun Wang
- Agro-Environmental
Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Maryam Davaritouchaee
- The
Gene & Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, United States
| | - Yiqing Yao
- College
of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China
| | - Kang Kang
- Institute
for Chemicals and Fuels from Alternative Resources (ICFAR), Western University, 22312 Wonderland Road North, London N0M 2A0, ON, Canada
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12
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Takada M, Chandra R, Wu J, Saddler JN. The influence of lignin on the effectiveness of using a chemithermomechanical pulping based process to pretreat softwood chips and pellets prior to enzymatic hydrolysis. BIORESOURCE TECHNOLOGY 2020; 302:122895. [PMID: 32019706 DOI: 10.1016/j.biortech.2020.122895] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
Over the last century the pulp and paper sector has assessed various technologies to fractionate woody biomass to produce strong, bright fibers. Several of these processes have also been assessed for their potential to pretreat and fractionate biomass to enhance the subsequent enzymatic hydrolysis of the cellulosic component. Although many of these pretreatments are effective on agricultural residues, softwoods have proven more recalcitrant, primarily due to their high lignin content and structure. As delignification is too expensive to be used routinely a more economically attractive approach might be to alter the lignin. Recent work has shown that, using a modified chemithermomechanical pulping (CTMP) "front end", lignin can be modified and relocated. This significantly enhanced hemicellulose recovery and enzyme-mediated cellulose hydrolysis of woody biomass. As well as being effective on wood chips, the modified CTMP pretreatment process also enhanced the bioconversion of densified feedstocks such as pellets.
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Affiliation(s)
- Masatsugu Takada
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada
| | - Richard Chandra
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada
| | - Jie Wu
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada
| | - John N Saddler
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada.
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13
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Yu G, Liu S, Feng X, Zhang Y, Liu C, Liu YJ, Li B, Cui Q, Peng H. Impact of ammonium sulfite-based sequential pretreatment combinations on two distinct saccharifications of wheat straw. RSC Adv 2020; 10:17129-17142. [PMID: 35521439 PMCID: PMC9053470 DOI: 10.1039/d0ra01759k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/22/2020] [Indexed: 01/27/2023] Open
Abstract
The properties of lignocellulosic substrates obtained from different pretreatments have a big impact on downstream saccharification based on both the fungal cellulase system and the cellulosome-based whole-cell biocatalysis system. However the corresponding effect of these two distinct saccharification strategies has not been comparatively analyzed. In this work, three ammonium sulfite (AS)-based pretreatment combinations (i.e., AS + hydrothermal (HT) pretreatment, AS + xylanase (X) pretreatment, and HT + AS pretreatment) were conducted to treat wheat straw. The obtained pretreated substrates with different properties were saccharified using fungal cellulase or an engineered Clostridium thermocellum strain as the whole-cell biocatalyst, and the ability to release sugar was comparatively evaluated. It was found that for the whole-cell saccharification, the total sugar digestibility of AS + HT/X pretreated wheat straw was 10% higher than that of HT + AS pretreated wheat straw. However, for fungal cellulase-based saccharification, the enzymatic hydrolysis efficiency was less susceptible to the sequence of pretreatment combinations. Hence, the whole-cell biocatalysis system was more sensitive to substrate accessibility compared to the free enzymes. In addition, the characterization and analyses showed that AS + HT/X pretreatment could remove more lignin, generating a more accessible surface with a larger external surface and lower surface lignin coverage, compared to the HT + AS pretreatment. Therefore, the AS + HT/X pretreatment was more compatible with the cellulosome-based whole-cell saccharification. The impact of substrate properties on wheat straw sugar release from fungal cellulase and whole cell-based CBS was comparatively investigated.![]()
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Affiliation(s)
- Guang Yu
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Shiyue Liu
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Xiaoyan Feng
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Yuedong Zhang
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Chao Liu
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Ya-Jun Liu
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Bin Li
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Qiu Cui
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
| | - Hui Peng
- CAS Key Laboratory of Biofuels
- Shandong Provincial Key Laboratory of Synthetic Biology
- Shandong Engineering Laboratory of Single Cell Oil
- Qingdao Engineering Laboratory of Single Cell Oil
- Dalian National Laboratory for Clean Energy
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14
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Takada M, Chandra RP, Saddler JN. The influence of lignin migration and relocation during steam pretreatment on the enzymatic hydrolysis of softwood and corn stover biomass substrates. Biotechnol Bioeng 2019; 116:2864-2873. [DOI: 10.1002/bit.27137] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/23/2019] [Accepted: 08/04/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Masatsugu Takada
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of ForestryUniversity of British Columbia Vancouver BC Canada
| | - Richard P. Chandra
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of ForestryUniversity of British Columbia Vancouver BC Canada
| | - John N. Saddler
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of ForestryUniversity of British Columbia Vancouver BC Canada
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15
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Fahmy M, Sohel MI, Vaidya AA, Jack MW, Suckling ID. Does sugar yield drive lignocellulosic sugar cost? Case study for enzymatic hydrolysis of softwood with added polyethylene glycol. Process Biochem 2019. [DOI: 10.1016/j.procbio.2019.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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16
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Enzymatic in situ saccharification of sugarcane bagasse pretreated with low loading of alkalic salts Na 2 SO 3 /Na 3 PO 4 by autoclaving. J Biotechnol 2017; 259:73-82. [DOI: 10.1016/j.jbiotec.2017.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/26/2017] [Accepted: 08/04/2017] [Indexed: 11/18/2022]
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17
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Tang Y, Dou X, Hu J, Jiang J, Saddler JN. Lignin Sulfonation and SO2 Addition Enhance the Hydrolyzability of Deacetylated and Then Steam-Pretreated Poplar with Reduced Inhibitor Formation. Appl Biochem Biotechnol 2017; 184:264-277. [DOI: 10.1007/s12010-017-2545-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/20/2017] [Indexed: 12/01/2022]
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18
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Suckling ID, Jack MW, Lloyd JA, Murton KD, Newman RH, Stuthridge TR, Torr KM, Vaidya AA. A mild thermomechanical process for the enzymatic conversion of radiata pine into fermentable sugars and lignin. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:61. [PMID: 28293291 PMCID: PMC5345204 DOI: 10.1186/s13068-017-0748-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 03/01/2017] [Indexed: 05/13/2023]
Abstract
BACKGROUND Conversion of softwoods into sustainable fuels and chemicals is important for parts of the world where softwoods are the dominant forest species. While they have high theoretical sugar yields, softwoods are amongst the most recalcitrant feedstocks for enzymatic processes, typically requiring both more severe pretreatment conditions and higher enzyme doses than needed for other lignocellulosic feedstocks. Although a number of processes have been proposed for converting softwoods into sugars suitable for fuel and chemical production, there is still a need for a high-yielding, industrially scalable and cost-effective conversion route. RESULTS We summarise work leading to the development of an efficient process for the enzymatic conversion of radiata pine (Pinus radiata) into wood sugars. The process involves initial pressurised steaming of wood chips under relatively mild conditions (173 °C for 3-72 min) without added acid catalyst. The steamed chips then pass through a compression screw to squeeze out a pressate rich in solubilised hemicelluloses. The pressed chips are disc-refined and wet ball-milled to produce a substrate which is rapidly saccharified using commercially available enzyme cocktails. Adding 0.1% polyethylene glycol during saccharification was found to be particularly effective with these substrates, reducing enzyme usage to acceptable levels, e.g. 5 FPU/g OD substrate. The pressate is separately hydrolysed using acid, providing additional hemicellulose-derived sugars, for an overall sugar yield of 535 kg/ODT chips (76% of theoretical). The total pretreatment energy input is comparable to other processes, with the additional energy for attrition being balanced by a lower thermal energy requirement. This pretreatment strategy produces substrates with low levels of fermentation inhibitors, so the glucose-rich mainline and pressate syrups can be fermented to ethanol without detoxification. The lignin from the process remains comparatively unmodified, as evident from the level of retained β-ether interunit linkages, providing an opportunity for conversion into saleable co-products. CONCLUSIONS This process is an efficient route for the enzymatic conversion of radiata pine, and potentially other softwoods, into a sugar syrup suitable for conversion into fuels and chemicals. Furthermore, the process uses standard equipment that is largely proven at commercial scale, de-risking process scale-up.
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Affiliation(s)
| | - Michael W. Jack
- Scion, 49 Sala St, Rotorua, 3046 New Zealand
- Department of Physics, University of Otago, PO Box 56, Dunedin, 9054 New Zealand
| | | | | | | | - Trevor R. Stuthridge
- Scion, 49 Sala St, Rotorua, 3046 New Zealand
- FP Innovations, 2665 East Mall, Vancouver, BC V6T 1Z4 Canada
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19
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Masran R, Zanirun Z, Bahrin EK, Ibrahim MF, Lai Yee P, Abd-Aziz S. Harnessing the potential of ligninolytic enzymes for lignocellulosic biomass pretreatment. Appl Microbiol Biotechnol 2016; 100:5231-46. [DOI: 10.1007/s00253-016-7545-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 04/07/2016] [Accepted: 04/12/2016] [Indexed: 01/15/2023]
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20
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Sui W, Chen H. Effects of water states on steam explosion of lignocellulosic biomass. BIORESOURCE TECHNOLOGY 2016; 199:155-163. [PMID: 26364827 DOI: 10.1016/j.biortech.2015.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
The work aimed to identify the complexity and roles of water states in steam explosion process of corn stalk to enhance the treatment efficiency. Results showed that two main water states with different mobility existed in corn stalk and influenced steam explosion treatment. By correlating dynamic water states data to feedstock mechanical properties and treatment process characteristics, the bound water being the excellent plasticizer that reduced the mechanical strength of fibers by over 30%, was conducive to treatment; while, the free water presenting buffering effects in treatment by hindering heat transfer which was reflected by the increase of temperature rising time by 1.29 folds and steam consumption by 2.18 folds, was not conducive. The distinguished point of these two waters was fiber saturated point. By considering treatment efficacy and energy consumption, the significance of fiber saturated point was highlighted as the optimal water states for steam explosion of corn stalk.
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Affiliation(s)
- Wenjie Sui
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Hongzhang Chen
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
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21
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Lu X, Zheng X, Li X, Zhao J. Adsorption and mechanism of cellulase enzymes onto lignin isolated from corn stover pretreated with liquid hot water. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:118. [PMID: 27274766 PMCID: PMC4891831 DOI: 10.1186/s13068-016-0531-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 05/19/2016] [Indexed: 05/02/2023]
Abstract
BACKGROUND In the bioconversion of lignocellulosic substrates, the adsorption behavior of cellulase onto lignin has a negative effect on enzymatic hydrolysis of cellulose, decreasing glucose production during enzymatic hydrolysis, thus decreasing the yield of fermentation and the production of useful products. Understanding the interaction between lignin and cellulase is necessary to optimize the components of cellulase mixture, genetically engineer high-efficiency cellulase, and reduce cost of bioconversion. Most lignin is not removed during liquid hot water (LHW) pretreatment, and the characteristics of lignin in solid substrate are also changed. To understand the interactions between cellulase and lignin, this study investigated the change in the characteristics of lignin obtained from corn stover, as well as the behavior of cellulase adsorption onto lignin, under various severities of LHW pretreatment. RESULTS LHW pretreatment removed most hemicellulose and some lignin in corn stover, as well as improved enzymatic digestibility of corn stover. After LHW pretreatment, the molecular weight of lignin obviously increased, whereas its polydispersity decreased and became more negative. The hydrophobicity and functional groups in lignin also changed. Adsorption of cellulase from Penicillium oxalicum onto lignin isolated from corn stover was enhanced after LHW pretreatment, and increased under increasing pretreatment severity. Different adsorption behaviors were observed in different lignin samples and components of cellulase mixtures, even in different cellobiohydrolases (CBHs), endo-beta-1, 4-glucanases (EGs). The greatest reduction in enzyme activity caused by lignin was observed in CBH, followed by that in xylanase and then in EG and β-Glucosidase (BGL). The adsorption behavior exerted different effects on subsequent enzymatic hydrolysis of various biomass substrates. Hydrophobic and electrostatic interactions may be important factors affecting different adsorption behaviors between lignin and cellulase. CONCLUSIONS LHW pretreatment changed the characteristics of the remaining lignin in corn stover, thus affected the adsorption behavior of lignin toward cellulase. For different protein components in cellulase solution from P. oxalicum, electrostatic action was a main factor influencing the adsorption of EG and xylanase onto lignin in corn stover, while hydrophobicity affected the adsorption of CBH and BGL onto lignin.
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Affiliation(s)
- Xianqin Lu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 Shandong China
| | - Xiaoju Zheng
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 Shandong China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 Shandong China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 Shandong China
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22
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Chandra RP, Chu Q, Hu J, Zhong N, Lin M, Lee JS, Saddler J. The influence of lignin on steam pretreatment and mechanical pulping of poplar to achieve high sugar recovery and ease of enzymatic hydrolysis. BIORESOURCE TECHNOLOGY 2016; 199:135-141. [PMID: 26391968 DOI: 10.1016/j.biortech.2015.09.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 05/05/2023]
Abstract
With the goal of enhancing overall carbohydrate recovery and reducing enzyme loading refiner mechanical pulping and steam pretreatment (210°C, 5 min) were used to pretreat poplar wood chips. Neutral sulphonation post-treatment indicated that, although the lignin present in the steam pretreated substrate was less reactive, the cellulose-rich, water insoluble component was more accessible to cellulases and Simons stain. This was likely due to lignin relocation as the relative surface lignin measured by X-ray photoelectron spectroscopy increased from 0.4 to 0.8. The integration of sulphite directly into steam pretreatment resulted in the solubilisation of 60% of the lignin while more than 80% of the carbohydrate present in the original substrate was recovered in the water insoluble fraction after Na2CO3 addition. More than 80% of the sugars present in the original cellulose and xylan could be recovered after 48 h using an enzyme loading of 20 mg protein/g cellulose at a 10% substrate concentration.
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Affiliation(s)
- Richard P Chandra
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, Faculty of Forestry, British Columbia, Canada
| | - QiuLu Chu
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, Faculty of Forestry, British Columbia, Canada
| | - Jinguang Hu
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, Faculty of Forestry, British Columbia, Canada
| | - Na Zhong
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, Faculty of Forestry, British Columbia, Canada
| | - Mandy Lin
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, Faculty of Forestry, British Columbia, Canada
| | - Jin-Suk Lee
- Clean Fuel Department, Korea Institute of Energy Research, Jeongeup, Jeonbuk 580-185, South Korea
| | - Jack Saddler
- Forest Products Biotechnology/Bioenergy Group, University of British Columbia, Faculty of Forestry, British Columbia, Canada
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23
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Bhalla A, Bansal N, Stoklosa RJ, Fountain M, Ralph J, Hodge DB, Hegg EL. Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:34. [PMID: 26862348 PMCID: PMC4746924 DOI: 10.1186/s13068-016-0442-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/20/2016] [Indexed: 05/11/2023]
Abstract
BACKGROUND Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H2O2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. RESULTS Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H2O2 was added batch-wise over the course of 10 h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H2O2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H2O2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin from untreated poplar. CONCLUSIONS This study demonstrated that the fed-batch, two-stage Cu-AHP pretreatment process was effective in pretreating hybrid poplar for its conversion into fermentable sugars. Results showed sugar yields near the theoretical maximum were achieved from enzymatically hydrolyzed hybrid poplar by incorporating an alkaline extraction step prior to pretreatment and by efficiently utilizing H2O2 during the Cu-AHP process. Significantly, this study reports high sugar yields from woody biomass treated with an AHP pretreatment under mild reaction conditions.
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Affiliation(s)
- Aditya Bhalla
- />DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
- />Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA
| | - Namita Bansal
- />DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
- />Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA
| | - Ryan J. Stoklosa
- />DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, USA
| | - Mackenzie Fountain
- />Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA
| | - John Ralph
- />DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, USA
| | - David B. Hodge
- />DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
- />Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, USA
- />Division of Sustainable Process Engineering, Luleå University of Technology, Luleå, Sweden
| | - Eric L. Hegg
- />DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
- />Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA
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24
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Yang Q, Pan X. Correlation between lignin physicochemical properties and inhibition to enzymatic hydrolysis of cellulose. Biotechnol Bioeng 2015; 113:1213-24. [DOI: 10.1002/bit.25903] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/15/2015] [Accepted: 12/07/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Qiang Yang
- Department of Biological Systems Engineering; University of Wisconsin-Madison; 460 Henry Mall Madison Wisconsin 53706
| | - Xuejun Pan
- Department of Biological Systems Engineering; University of Wisconsin-Madison; 460 Henry Mall Madison Wisconsin 53706
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25
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Joelsson E, Wallberg O, Börjesson P. Integration potential, resource efficiency and cost of forest-fuel-based biorefineries. Comput Chem Eng 2015. [DOI: 10.1016/j.compchemeng.2015.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Agrawal R, Satlewal A, Gaur R, Mathur A, Kumar R, Gupta RP, Tuli DK. Pilot scale pretreatment of wheat straw and comparative evaluation of commercial enzyme preparations for biomass saccharification and fermentation. Biochem Eng J 2015. [DOI: 10.1016/j.bej.2015.02.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Ji Z, Zhang X, Ling Z, Zhou X, Ramaswamy S, Xu F. Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:103. [PMID: 26213569 PMCID: PMC4513789 DOI: 10.1186/s13068-015-0282-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 07/01/2015] [Indexed: 05/19/2023]
Abstract
BACKGROUND The natural recalcitrance of lignocellulosic plant cell walls resulting from complex arrangement and distribution of heterogeneous components impedes deconstruction of such cell walls. Dilute acid pretreatment (DAP) is an attractive method to overcome the recalcitrant barriers for rendering enzymatic conversion of polysaccharides. In this study, the internodes of Miscanthus × giganteus, a model bioenergy crop, were subjected to DAP to yield a range of samples with altered cell wall structure and chemistry. The consequent morphological and compositional changes and their possible impact on saccharification efficiency were comprehensively investigated. The use of a series of microscopic and microspectroscopic techniques including fluorescence microscopy (FM), transmission electron microscopy (TEM) and confocal Raman microscopy (CRM)) enabled correlative cell wall structural and chemical information to be obtained. RESULTS DAP of M. × giganteus resulted in solubilization of arabinoxylan and cross-linking hydroxycinnamic acids in a temperature-dependent manner. The optimized pretreatment (1% H2SO4, 170°C for 30 min) resulted in significant enhancement in the saccharification efficiency (51.20%) of treated samples in 72 h, which amounted to 4.4-fold increase in sugar yield over untreated samples (11.80%). The remarkable improvement could be correlated to a sequence of changes occurring in plant cell walls due to their pretreatment-induced deconstruction, namely, loss in the matrix between neighboring cell walls, selective removal of hemicelluloses, redistribution of phenolic polymers and increased exposure of cellulose. The consequently occurred changes in inner cell wall structure including damaging, increase of porosity and loss of mechanical resistance were also found to enhance enzyme access to cellulose and further sugar yield. CONCLUSIONS DAP is a highly effective process for improving bioconversion of cellulose to glucose by breaking down the rigidity and resistance of cell walls. The combination of the most relevant microscopic and microanalytical techniques employed in this work provided information crucial for evaluating the influence of anatomical and compositional changes on enhanced enzymatic digestibility.
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Affiliation(s)
- Zhe Ji
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
- />Ministry of Education Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Tsinghua East Road, Beijing, 100083 China
| | - Xun Zhang
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
- />Ministry of Education Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Tsinghua East Road, Beijing, 100083 China
| | - Zhe Ling
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
- />Ministry of Education Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Tsinghua East Road, Beijing, 100083 China
| | - Xia Zhou
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
- />Ministry of Education Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Tsinghua East Road, Beijing, 100083 China
| | - Shri Ramaswamy
- />Department of Bioproducts and Biosystems Engineering, Kaufert Laboratory, University of Minnesota, Saint Paul, MN 55108 USA
| | - Feng Xu
- />Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
- />Ministry of Education Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Tsinghua East Road, Beijing, 100083 China
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Meineke T, Manisseri C, Voigt CA. Phylogeny in defining model plants for lignocellulosic ethanol production: a comparative study of Brachypodium distachyon, wheat, maize, and Miscanthus x giganteus leaf and stem biomass. PLoS One 2014; 9:e103580. [PMID: 25133818 PMCID: PMC4136770 DOI: 10.1371/journal.pone.0103580] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 07/04/2014] [Indexed: 12/26/2022] Open
Abstract
The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108-117 mg ethanol·g(-1) dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type.
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Affiliation(s)
- Till Meineke
- Phytopathology & Biochemistry, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Chithra Manisseri
- Phytopathology & Biochemistry, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Christian A. Voigt
- Phytopathology & Biochemistry, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
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Chen CZ, Li MF, Wu YY, Sun RC. Integration of Ambient Formic Acid Process and Alkaline Hydrogen Peroxide Post-Treatment of Furfural Residue To Enhance Enzymatic Hydrolysis. Ind Eng Chem Res 2014. [DOI: 10.1021/ie502303s] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chang-Zhou Chen
- Beijing
Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China
| | - Ming-Fei Li
- Beijing
Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China
| | - Yu-Ying Wu
- Beijing
Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China
| | - Run-Cang Sun
- Beijing
Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China
- State
Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
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30
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Effect of Double-Step Steam Explosion Pretreatment in Bioethanol Production from Softwood. Appl Biochem Biotechnol 2014; 174:156-67. [DOI: 10.1007/s12010-014-1046-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
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31
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Meng X, Ragauskas AJ. Recent advances in understanding the role of cellulose accessibility in enzymatic hydrolysis of lignocellulosic substrates. Curr Opin Biotechnol 2014; 27:150-8. [DOI: 10.1016/j.copbio.2014.01.014] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/08/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
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He Y, Zhang J, Bao J. Dry dilute acid pretreatment by co-currently feeding of corn stover feedstock and dilute acid solution without impregnation. BIORESOURCE TECHNOLOGY 2014; 158:360-4. [PMID: 24630497 DOI: 10.1016/j.biortech.2014.02.074] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 02/19/2014] [Indexed: 05/27/2023]
Abstract
Impregnation of lignocellulose materials with dilute acid solution is a routine operation in conventional dilute acid pretreatment. The dry dilute acid pretreatment (DDAP) at high solids content up to 70% is naturally considered to require longer impregnation time. In this study, a co-currently feeding operation of corn stover and dilute sulfuric acid solution without any impregnation was tested for DDAP. The DDAP pretreated corn stover without impregnation is found to be essentially no difference in pretreatment efficiency compared to those with impregnation in the helically agitated reactor. The yield from cellulose to ethanol in SSF again shows no obvious difference between the DDAP pretreated corn stover with and without impregnation. This study suggests that impregnation in DDAP was not necessary under the helical agitation mixing. The results provided a useful way of cost reduction and process simplification in pretreatment.
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Affiliation(s)
- Yanqing He
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jian Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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33
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Lee DS, Wi SG, Lee SJ, Lee YG, Kim YS, Bae HJ. Rapid saccharification for production of cellulosic biofuels. BIORESOURCE TECHNOLOGY 2014; 158:239-47. [PMID: 24607460 DOI: 10.1016/j.biortech.2014.02.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 02/07/2014] [Accepted: 02/10/2014] [Indexed: 05/11/2023]
Abstract
The economical production of biofuels is hindered by the recalcitrance of lignocellulose to processing, causing high consumption of processing enzymes and impeding hydrolysis of pretreated lignocellulosic biomass. We determined the major rate-limiting factor in the hydrolysis of popping pre-treated rice straw (PPRS) by examining cellulase adsorption to lignin and cellulose, amorphogenesis of PPRS, and re-hydrolysis. Based on the results, equivalence between enzyme loading and the open structural area of cellulose was required to significantly increase productive adsorption of cellulase and to accelerate enzymatic saccharification of PPRS. Amorphogenesis of PPRS by phosphoric acid treatment to expand open structural area of the cellulose fibers resulted in twofold higher cellulase adsorption and increased the yield of the first re-hydrolysis step from 13% to 46%. The total yield from PPRS was increased to 84% after 3h. These results provide evidence that cellulose structure is one of major effects on the enzymatic hydrolysis.
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Affiliation(s)
- Dae-Seok Lee
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Seung Gon Wi
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Soo Jung Lee
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Yoon-Gyo Lee
- Department of Forest Products and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Yeong-Suk Kim
- Department of Forest Products, Kookmin University, Seoul 136-702, Republic of Korea
| | - Hyeun-Jong Bae
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea; Department of Forest Products and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea; Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea.
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34
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Nordwald EM, Brunecky R, Himmel ME, Beckham GT, Kaar JL. Charge engineering of cellulases improves ionic liquid tolerance and reduces lignin inhibition. Biotechnol Bioeng 2014; 111:1541-9. [DOI: 10.1002/bit.25216] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/27/2014] [Accepted: 02/06/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Erik M. Nordwald
- Department of Chemical and Biological Engineering; University of Colorado; Campus Box 596 Boulder Colorado 80309
| | - Roman Brunecky
- Biosciences Center; National Renewable Energy Laboratory; Golden Colorado
| | - Michael E. Himmel
- Biosciences Center; National Renewable Energy Laboratory; Golden Colorado
| | - Gregg T. Beckham
- National Bioenergy Center; National Renewable Energy Laboratory; Golden Colorado
| | - Joel L. Kaar
- Department of Chemical and Biological Engineering; University of Colorado; Campus Box 596 Boulder Colorado 80309
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Rodrigues AC, Felby C, Gama M. Cellulase stability, adsorption/desorption profiles and recycling during successive cycles of hydrolysis and fermentation of wheat straw. BIORESOURCE TECHNOLOGY 2014; 156:163-9. [PMID: 24502914 DOI: 10.1016/j.biortech.2014.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Revised: 01/03/2014] [Accepted: 01/06/2014] [Indexed: 05/11/2023]
Abstract
The potential of enzymes recycling after hydrolysis and fermentation of wheat straw under a variety of conditions was investigated, monitoring the activity of the enzymes in the solid and liquid fractions, using low molecular weight substrates. A significant amount of active enzymes could be recovered by recycling the liquid phase. In the early stage of the process, enzyme adsorb to the substrate, then gradually returning to the solution as the saccharification proceeds. At 50°C, normally regarded as an acceptable operational temperature for saccharification, the enzymes (Celluclast) significantly undergo thermal deactivation. The hydrolysis yield and enzyme recycling efficiency in consecutive recycling rounds can be increased by using high enzyme loadings and moderate temperatures. Indeed, the amount of enzymes in the liquid phase increased with its thermostability and hydrolytic efficiency. This study contributes towards developing effective enzymes recycling strategies and helping to reduce the enzyme costs on bioethanol production.
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Affiliation(s)
- Ana Cristina Rodrigues
- Centro de Engenharia Biológica, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Claus Felby
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark.
| | - Miguel Gama
- Centro de Engenharia Biológica, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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36
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Hu J, Arantes V, Pribowo A, Saddler JN. The synergistic action of accessory enzymes enhances the hydrolytic potential of a "cellulase mixture" but is highly substrate specific. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:112. [PMID: 23915398 PMCID: PMC3750293 DOI: 10.1186/1754-6834-6-112] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 08/02/2013] [Indexed: 05/05/2023]
Abstract
BACKGROUND Currently, the amount of protein/enzyme required to achieve effective cellulose hydrolysis is still too high. One way to reduce the amount of protein/enzyme required is to formulate a more efficient enzyme cocktail by adding so-called accessory enzymes such as xylanase, lytic polysaccharide monooxygenase (AA9, formerly known as GH61), etc., to the cellulase mixture. Previous work has shown the strong synergism that can occur between cellulase and xylanase mixtures during the hydrolysis of steam pretreated corn stover, requiring lower protein loading to achieve effective hydrolysis. However, relatively high loadings of xylanases were required. When family 10 and 11 endo-xylanases and family 5 xyloglucanase were supplemented to a commercial cellulase mixture varying degrees of improved hydrolysis over a range of pretreated, lignocellulosic substrates were observed. RESULTS The potential synergistic interactions between cellulase monocomponents and hemicellulases from family 10 and 11 endo-xylanases (GH10 EX and GH11 EX) and family 5 xyloglucanase (GH5 XG), during hydrolysis of various steam pretreated lignocellulosic substrates, were assessed. It was apparent that the hydrolytic activity of cellulase monocomponents was enhanced by the addition of accessory enzymes although the "boosting" effect was highly substrate specific. The GH10 EX and GH5 XG both exhibited broad substrate specificity and showed strong synergistic interaction with the cellulases when added individually. The GH10 EX was more effective on steam pretreated agriculture residues and hardwood substrates whereas GH5 XG addition was more effective on softwood substrates. The synergistic interaction between GH10 EX and GH5 XG when added together further enhanced the hydrolytic activity of the cellulase enzymes over a range of pretreated lignocellulosic substrates. GH10 EX addition could also stimulate further cellulose hydrolysis when added to the hydrolysis reactions when the rate of hydrolysis had levelled off. CONCLUSIONS Endo-xylanases and xyloglucanases interacted synergistically with cellulases to improve the hydrolysis of a range of pretreated lignocellulosic substrates. However, the extent of improved hydrolysis was highly substrate dependent. It appears that those accessory enzymes, such as GH10 EX and GH5 XG, with broader substrate specificities promoted the greatest improvements in the hydrolytic performance of the cellulase mixture on all of the pretreated biomass substrates.
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Affiliation(s)
- Jinguang Hu
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Valdeir Arantes
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Amadeus Pribowo
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jack N Saddler
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
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37
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Lacayo CI, Hwang MS, Ding SY, Thelen MP. Lignin depletion enhances the digestibility of cellulose in cultured xylem cells. PLoS One 2013; 8:e68266. [PMID: 23874568 PMCID: PMC3715489 DOI: 10.1371/journal.pone.0068266] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 05/23/2013] [Indexed: 01/15/2023] Open
Abstract
Plant lignocellulose constitutes an abundant and sustainable source of polysaccharides that can be converted into biofuels. However, the enzymatic digestion of native plant cell walls is inefficient, presenting a considerable barrier to cost-effective biofuel production. In addition to the insolubility of cellulose and hemicellulose, the tight association of lignin with these polysaccharides intensifies the problem of cell wall recalcitrance. To determine the extent to which lignin influences the enzymatic digestion of cellulose, specifically in secondary walls that contain the majority of cellulose and lignin in plants, we used a model system consisting of cultured xylem cells from Zinniaelegans. Rather than using purified cell wall substrates or plant tissue, we have applied this system to study cell wall degradation because it predominantly consists of homogeneous populations of single cells exhibiting large deposits of lignocellulose. We depleted lignin in these cells by treating with an oxidative chemical or by inhibiting lignin biosynthesis, and then examined the resulting cellulose digestibility and accessibility using a fluorescent cellulose-binding probe. Following cellulase digestion, we measured a significant decrease in relative cellulose content in lignin-depleted cells, whereas cells with intact lignin remained essentially unaltered. We also observed a significant increase in probe binding after lignin depletion, indicating that decreased lignin levels improve cellulose accessibility. These results indicate that lignin depletion considerably enhances the digestibility of cellulose in the cell wall by increasing the susceptibility of cellulose to enzymatic attack. Although other wall components are likely to contribute, our quantitative study exploits cultured Zinnia xylem cells to demonstrate the dominant influence of lignin on the enzymatic digestion of the cell wall. This system is simple enough for quantitative image analysis, but realistic enough to capture the natural complexity of lignocellulose in the plant cell wall. Consequently, these cells represent a suitable model for analyzing native lignocellulose degradation.
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Affiliation(s)
- Catherine I. Lacayo
- Physical & Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Mona S. Hwang
- Physical & Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Shi-You Ding
- Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, United States of America
| | - Michael P. Thelen
- Physical & Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
- * E-mail:
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38
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Burkhardt S, Kumar L, Chandra R, Saddler J. How effective are traditional methods of compositional analysis in providing an accurate material balance for a range of softwood derived residues? BIOTECHNOLOGY FOR BIOFUELS 2013; 6:90. [PMID: 23800175 PMCID: PMC3704954 DOI: 10.1186/1754-6834-6-90] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/11/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Forest residues represent an abundant and sustainable source of biomass which could be used as a biorefinery feedstock. Due to the heterogeneity of forest residues, such as hog fuel and bark, one of the expected challenges is to obtain an accurate material balance of these feedstocks. Current compositional analytical methods have been standardised for more homogenous feedstocks such as white wood and agricultural residues. The described work assessed the accuracy of existing and modified methods on a variety of forest residues both before and after a typical pretreatment process. RESULTS When "traditional" pulp and paper methods were used, the total amount of material that could be quantified in each of the six softwood-derived residues ranged from 88% to 96%. It was apparent that the extractives present in the substrate were most influential in limiting the accuracy of a more representative material balance. This was particularly evident when trying to determine the lignin content, due to the incomplete removal of the extractives, even after a two stage water-ethanol extraction. Residual extractives likely precipitated with the acid insoluble lignin during analysis, contributing to an overestimation of the lignin content. Despite the minor dissolution of hemicellulosic sugars, extraction with mild alkali removed most of the extractives from the bark and improved the raw material mass closure to 95% in comparison to the 88% value obtained after water-ethanol extraction. After pretreatment, the extent of extractive removal and their reaction/precipitation with lignin was heavily dependent on the pretreatment conditions used. The selective removal of extractives and their quantification after a pretreatment proved to be even more challenging. Regardless of the amount of extractives that were originally present, the analytical methods could be refined to provide reproducible quantification of the carbohydrates present in both the starting material and after pretreatment. CONCLUSION Despite the challenges resulting from the heterogeneity of the initial biomass substrates a reasonable summative mass closure could be obtained before and after steam pretreatment. However, method revision and optimisation was required, particularly the effective removal of extractives, to ensure that representative and reproducible values for the major lignin and carbohydrate components.
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Affiliation(s)
- Sabrina Burkhardt
- Forest Products Biotechnology/Bioenergy, 2424 Main Mall University of British Columbia, Greater Vancouver, Canada
| | - Linoj Kumar
- Forest Products Biotechnology/Bioenergy, 2424 Main Mall University of British Columbia, Greater Vancouver, Canada
| | - Richard Chandra
- Forest Products Biotechnology/Bioenergy, 2424 Main Mall University of British Columbia, Greater Vancouver, Canada
| | - Jack Saddler
- Forest Products Biotechnology/Bioenergy, 2424 Main Mall University of British Columbia, Greater Vancouver, Canada
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39
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Kang Y, Bansal P, Realff MJ, Bommarius AS. SO2-catalyzed steam explosion: The effects of different severity on digestibility, accessibility, and crystallinity of lignocellulosic biomass. Biotechnol Prog 2013; 29:909-16. [DOI: 10.1002/btpr.1751] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 04/16/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Yuzhi Kang
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology; Atlanta GA 30332-0100
| | - Prabuddha Bansal
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology; Atlanta GA 30332-0100
| | - Matthew J. Realff
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology; Atlanta GA 30332-0100
| | - Andreas S. Bommarius
- School of Chemistry and Biochemistry, Georgia Institute of Technology; Atlanta GA 30332-0400
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40
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Mendes FM, Laurito DF, Bazzeggio M, Ferraz A, Milagres AMF. Enzymatic digestion of alkaline-sulfite pretreated sugar cane bagasse and its correlation with the chemical and structural changes occurring during the pretreatment step. Biotechnol Prog 2013; 29:890-5. [DOI: 10.1002/btpr.1746] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/13/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Fernanda M. Mendes
- Dept. de Biotecnologia, Escola de Engenharia de Lorena; Universidade de São Paulo; 12602-810 Lorena São Paulo Brasil
| | - Debora F. Laurito
- Dept. de Biotecnologia, Escola de Engenharia de Lorena; Universidade de São Paulo; 12602-810 Lorena São Paulo Brasil
| | - Mariana Bazzeggio
- Dept. de Biotecnologia, Escola de Engenharia de Lorena; Universidade de São Paulo; 12602-810 Lorena São Paulo Brasil
| | - André Ferraz
- Dept. de Biotecnologia, Escola de Engenharia de Lorena; Universidade de São Paulo; 12602-810 Lorena São Paulo Brasil
| | - Adriane M. F. Milagres
- Dept. de Biotecnologia, Escola de Engenharia de Lorena; Universidade de São Paulo; 12602-810 Lorena São Paulo Brasil
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41
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Lou H, Zhu JY, Lan TQ, Lai H, Qiu X. pH-Induced lignin surface modification to reduce nonspecific cellulase binding and enhance enzymatic saccharification of lignocelluloses. CHEMSUSCHEM 2013; 6:919-27. [PMID: 23554287 DOI: 10.1002/cssc.201200859] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Indexed: 05/02/2023]
Abstract
We studied the mechanism of the significant enhancement in the enzymatic saccharification of lignocelluloses at an elevated pH of 5.5-6.0. Four lignin residues with different sulfonic acid contents were isolated from enzymatic hydrolysis of lodgepole pine pretreated by either dilute acid (DA) or sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL). The adsorption isotherms of a commercial Trichoderma reesi cellulase cocktail (CTec2) produced by these lignin residues at 50 °C were measured in the pH range of 4.5-6.0. The zeta potentials of these lignin samples were also measured. We discovered that an elevated pH significantly increased the lignin surface charge (negative), which causes lignin to become more hydrophilic and reduces its coordination affinity to cellulase and, consequently, the nonspecific binding of cellulase. The decreased nonspecific cellulase binding to lignin is also attributed to enhanced electrostatic interactions at elevated pH through the increased negative charges of cellulase enzymes with low pI. The results validate the hypothesis that the increases in enzymatic saccharification efficiencies at elevated pH for different pretreated lignocelluloses are solely the result of decreased nonspecific cellulase binding to lignin. This study contradicts the well-established concept that the optimal pH is 4.8-5.0 for enzymatic hydrolysis using Trichoderma reesi cellulose, which is widely accepted and exclusively practiced in numerous laboratories throughout the world. Because an elevated pH can be easily implemented commercially without capital cost and with minimal operating cost, this study has both scientific importance and practical significance.
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Affiliation(s)
- Hongming Lou
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, PR China
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42
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Wang ZJ, Lan TQ, Zhu JY. Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:9. [PMID: 24188090 PMCID: PMC3563490 DOI: 10.1186/1754-6834-6-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/13/2012] [Indexed: 05/02/2023]
Abstract
BACKGROUND Nonspecific (nonproductive) binding (adsorption) of cellulase by lignin has been identified as a key barrier to reduce cellulase loading for economical sugar and biofuel production from lignocellulosic biomass. Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL) is a relatively new process, but demonstrated robust performance for sugar and biofuel production from woody biomass especially softwoods in terms of yields and energy efficiencies. This study demonstrated the role of lignin sulfonation in enhancing enzymatic saccharification of lignocelluloses - lignosulfonate from SPORL can improve enzymatic hydrolysis of lignocelluloses, contrary to the conventional belief that lignin inhibits enzymatic hydrolysis due to nonspecific binding of cellulase. RESULTS The study found that lignosulfonate from SPORL pretreatment and from a commercial source inhibits enzymatic hydrolysis of pure cellulosic substrates at low concentrations due to nonspecific binding of cellulase. Surprisingly, the reduction in enzymatic saccharification efficiency of a lignocellulosic substrate was fully recovered as the concentrations of these two lignosulfonates increased. We hypothesize that lignosulfonate serves as a surfactant to enhance enzymatic hydrolysis at higher concentrations and that this enhancement offsets its inhibitive effect from nonspecific binding of cellulase, when lignosulfonate is applied to lignocellulosic solid substrates. Lignosulfonate can block nonspecific binding of cellulase by bound lignin on the solid substrates, in the same manner as a nonionic surfactant, to significantly enhance enzymatic saccharification. This enhancement is linearly proportional to the amount of lignosulfonate applied which is very important to practical applications. For a SPORL-pretreated lodgepole pine solid, 90% cellulose saccharification was achieved at cellulase loading of 13 FPU/g glucan with the application of its corresponding pretreatment hydrolysate coupled with increasing hydrolysis pH to above 5.5 compared with only 51% for the control run without lignosulfonate at pH 5.0. The pH-induced lignin surface modification at pH 5.5 further reduced nonspecific binding of cellulase by lignosulfonate. CONCLUSIONS The results reported in this study suggest significant advantages for SPORL-pretreatment in terms of reducing water usage and enzyme dosage, and simplifying process integration, i.e., it should eliminate washing of SPORL solid fraction for direct simultaneous enzymatic saccharification and combined fermentation of enzymatic and pretreatment hydrolysates (SSCombF). Elevated pH 5.5 or higher, rather than the commonly believed optimal and widely practiced pH 4.8-5.0, should be used in conducting enzymatic saccharification of lignocelluloses.
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Affiliation(s)
- ZJ Wang
- Key Lab of Paper Science & Technology, Shandong Polytechnic University, Jinan, China
- US Forest Service, Forest Products Laboratory, Madison, WI, USA
| | - TQ Lan
- US Forest Service, Forest Products Laboratory, Madison, WI, USA
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
| | - JY Zhu
- US Forest Service, Forest Products Laboratory, Madison, WI, USA
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43
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Pu Y, Hu F, Huang F, Davison BH, Ragauskas AJ. Assessing the molecular structure basis for biomass recalcitrance during dilute acid and hydrothermal pretreatments. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:15. [PMID: 23356640 PMCID: PMC3575271 DOI: 10.1186/1754-6834-6-15] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/14/2013] [Indexed: 05/04/2023]
Abstract
The production of cellulosic ethanol from biomass is considered a promising alternative to reliance on diminishing supplies of fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The conversion of lignocellulosic biomass to biofuels through a biological route usually suffers from the intrinsic recalcitrance of biomass owing to the complicated structure of plant cell walls. Currently, a pretreatment step that can effectively reduce biomass recalcitrance is generally required to make the polysaccharide fractions locked in the intricacy of plant cell walls to become more accessible and amenable to enzymatic hydrolysis. Dilute acid and hydrothermal pretreatments are attractive and among the most promising pretreatment technologies that enhance sugar release performance. This review highlights our recent understanding on molecular structure basis for recalcitrance, with emphasis on structural transformation of major biomass biopolymers (i.e., cellulose, hemicellulose, and lignin) related to the reduction of recalcitrance during dilute acid and hydrothermal pretreatments. The effects of these two pretreatments on biomass porosity as well as its contribution on reduced recalcitrance are also discussed.
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Affiliation(s)
- Yunqiao Pu
- Institute of Paper Science and Technology, Georgia Institute of Technology, Atlanta, GA, USA
- BioEnergy Science Center, Oak Ridge, TN, USA
| | - Fan Hu
- BioEnergy Science Center, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
- BioEnergy Science Center, Oak Ridge, TN, USA
| | - Fang Huang
- BioEnergy Science Center, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
- BioEnergy Science Center, Oak Ridge, TN, USA
| | - Brian H Davison
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- BioEnergy Science Center, Oak Ridge, TN, USA
| | - Arthur J Ragauskas
- Institute of Paper Science and Technology, Georgia Institute of Technology, Atlanta, GA, USA
- BioEnergy Science Center, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
- BioEnergy Science Center, Oak Ridge, TN, USA
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Bu L, Xing Y, Yu H, Gao Y, Jiang J. Comparative study of sulfite pretreatments for robust enzymatic saccharification of corn cob residue. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:87. [PMID: 23206858 PMCID: PMC3537520 DOI: 10.1186/1754-6834-5-87] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/26/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND Corn cob residue (CCR) is a kind of waste lignocellulosic material with enormous potential for bioethanol production. The moderated sulphite processes were used to enhance the hydrophily of the material by sulfonation and hydrolysis. The composition, FT-IR spectra, and conductometric titrations of the pretreated materials were measured to characterize variations of the CCR in different sulfite pretreated environments. And the objective of this study is to compare the saccharification rate and yield of the samples caused by these variations. RESULTS It was found that the lignin in the CCR (43.2%) had reduced to 37.8%, 38.0%, 35.9%, and 35.5% after the sulfite pretreatment in neutral, acidic, alkaline, and ethanol environments, respectively. The sulfite pretreatments enhanced the glucose yield of the CCR. Moreover, the ethanol sulfite sample had the highest glucose yield (81.2%, based on the cellulose in the treated sample) among the saccharification samples, which was over 10% higher than that of the raw material (70.6%). More sulfonic groups and weak acid groups were produced during the sulfite pretreatments. Meanwhile, the ethanol sulfite treated sample had the highest sulfonic group (0.103 mmol/g) and weak acid groups (1.85 mmol/g) in all sulfite treated samples. In FT-IR spectra, the variation of bands at 1168 and 1190 cm-1 confirmed lignin sulfonation during sulfite pretreatment. The disappearance of the band at 1458 cm-1 implied the methoxyl on lignin had been removed during the sulfite pretreatments. CONCLUSIONS It can be concluded that the lignin in the CCR can be degraded and sulfonated during the sulfite pretreatments. The pretreatments improve the hydrophility of the samples because of the increase in sulfonic group and weak acid groups, which enhances the glucose yield of the material. The ethanol sulfite pretreatment is the best method for lignin removal and with the highest glucose yield.
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Affiliation(s)
- Lingxi Bu
- Department of Chemistry and Chemical Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yang Xing
- Department of Chemistry and Chemical Engineering, Beijing Forestry University, Beijing 100083, China
| | - Hailong Yu
- Department of Chemistry and Chemical Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yuxia Gao
- Department of Chemistry and Chemical Engineering, Beijing Forestry University, Beijing 100083, China
| | - Jianxin Jiang
- Department of Chemistry and Chemical Engineering, Beijing Forestry University, Beijing 100083, China
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Yuan TQ, Wang W, Zhang LM, Xu F, Sun RC. Reconstitution of cellulose and lignin after [C2mim][OAc] pretreatment and its relation to enzymatic hydrolysis. Biotechnol Bioeng 2012; 110:729-36. [DOI: 10.1002/bit.24743] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 07/30/2012] [Accepted: 09/25/2012] [Indexed: 11/10/2022]
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Kumar L, Tooyserkani Z, Sokhansanj S, Saddler JN. Does densification influence the steam pretreatment and enzymatic hydrolysis of softwoods to sugars? BIORESOURCE TECHNOLOGY 2012; 121:190-198. [PMID: 22858485 DOI: 10.1016/j.biortech.2012.06.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/14/2012] [Accepted: 06/15/2012] [Indexed: 06/01/2023]
Abstract
The global trade in wood pellets continues to grow. However, their potential as a feedstock for large scale cellulosic ethanol production has not been evaluated. We anticipated that the reduced moisture content and pressure exerted on the wood biomass during the pelletisation process would result in some carbohydrate loss as well as making the biomass more recalcitrant to pretreatment and subsequent hydrolysis. However, when softwood chips and pellets were steam pretreated at medium severity, little hemicellulose loss occurred while more than two-thirds of the cellulose present in the cellulose rich water insoluble fractions were hydrolysed (at 20 FPU cellulase/g cellulose). In addition, prior steaming substantially reduced the particle size of the wood chips enabling direct pelletisation without the need for grinding. Surprisingly, it was also possible to apply a single steam pretreatment to facilitate both pelletisation and subsequent enzymatic hydrolysis without the need for a further pretreatment step.
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Affiliation(s)
- Linoj Kumar
- Forest Products Biotechnology/Bioenergy, University of British Columbia, Vancouver, BC, Canada
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Li M, Foster C, Kelkar S, Pu Y, Holmes D, Ragauskas A, Saffron CM, Hodge DB. Structural characterization of alkaline hydrogen peroxide pretreated grasses exhibiting diverse lignin phenotypes. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:38. [PMID: 22672858 PMCID: PMC3443053 DOI: 10.1186/1754-6834-5-38] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 02/27/2012] [Indexed: 05/08/2023]
Abstract
BACKGROUND For cellulosic biofuels processes, suitable characterization of the lignin remaining within the cell wall and correlation of quantified properties of lignin to cell wall polysaccharide enzymatic deconstruction is underrepresented in the literature. This is particularly true for grasses which represent a number of promising bioenergy feedstocks where quantification of grass lignins is particularly problematic due to the high fraction of p-hydroxycinnamates. The main focus of this work is to use grasses with a diverse range of lignin properties, and applying multiple lignin characterization platforms, attempt to correlate the differences in these lignin properties to the susceptibility to alkaline hydrogen peroxide (AHP) pretreatment and subsequent enzymatic deconstruction. RESULTS We were able to determine that the enzymatic hydrolysis of cellulose to to glucose (i.e. digestibility) of four grasses with relatively diverse lignin phenotypes could be correlated to total lignin content and the content of p-hydroxycinnamates, while S/G ratios did not appear to contribute to the enzymatic digestibility or delignification. The lignins of the brown midrib corn stovers tested were significantly more condensed than a typical commercial corn stover and a significant finding was that pretreatment with alkaline hydrogen peroxide increases the fraction of lignins involved in condensed linkages from 88-95% to ~99% for all the corn stovers tested, which is much more than has been reported in the literature for other pretreatments. This indicates significant scission of β-O-4 bonds by pretreatment and/or induction of lignin condensation reactions. The S/G ratios in grasses determined by analytical pyrolysis are significantly lower than values obtained using either thioacidolysis or 2DHSQC NMR due to presumed interference by ferulates. CONCLUSIONS It was found that grass cell wall polysaccharide hydrolysis by cellulolytic enzymes for grasses exhibiting a diversity of lignin structures and compositions could be linked to quantifiable changes in the composition of the cell wall and properties of the lignin including apparent content of the p-hydroxycinnamates while the limitations of S/G estimation in grasses is highlighted.
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Affiliation(s)
- Muyang Li
- Department of Biosystems and Agricultural Engineering, Michigan State University, Michigan, USA
- DOE Great Lakes Bioenergy Research Center, Michigan State University, Michigan, USA
| | - Cliff Foster
- DOE Great Lakes Bioenergy Research Center, Michigan State University, Michigan, USA
| | - Shantanu Kelkar
- Department of Biosystems and Agricultural Engineering, Michigan State University, Michigan, USA
- Department of Chemical Engineering and Materials Science, Michigan State University, Michigan, USA
| | - Yunqiao Pu
- DOE BioEnergy Science Center, Georgia Institute of Technology, Georgia, USA
| | - Daniel Holmes
- Department of Chemistry, Michigan State University, Michigan, USA
| | - Arthur Ragauskas
- DOE BioEnergy Science Center, Georgia Institute of Technology, Georgia, USA
- Department of Chemistry and Biochemistry, Georgia Institute of Technology, Georgia, USA
- Institute of Paper Science and Technology, Georgia Institute of Technology, Georgia, USA
| | - Christopher M Saffron
- Department of Biosystems and Agricultural Engineering, Michigan State University, Michigan, USA
- Department of Chemical Engineering and Materials Science, Michigan State University, Michigan, USA
- Department of Forestry, Michigan State University, Michigan, USA
| | - David B Hodge
- Department of Biosystems and Agricultural Engineering, Michigan State University, Michigan, USA
- DOE Great Lakes Bioenergy Research Center, Michigan State University, Michigan, USA
- Department of Chemical Engineering and Materials Science, Michigan State University, Michigan, USA
- Department of Chemical Engineering and Materials Science, Michigan State University, Michigan, USA
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Extrusion Pretreatment of Pine Wood Chips. Appl Biochem Biotechnol 2012; 167:81-99. [DOI: 10.1007/s12010-012-9662-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 03/28/2012] [Indexed: 10/28/2022]
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Wang Q, Zhu J, Hunt C, Zhan H. Kinetics of adsorption, desorption, and re-adsorption of a commercial endoglucanase in lignocellulosic suspensions. Biotechnol Bioeng 2012; 109:1965-75. [DOI: 10.1002/bit.24483] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 02/02/2012] [Accepted: 02/13/2012] [Indexed: 11/06/2022]
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Arantes V, Jellison J, Goodell B. Peculiarities of brown-rot fungi and biochemical Fenton reaction with regard to their potential as a model for bioprocessing biomass. Appl Microbiol Biotechnol 2012; 94:323-38. [DOI: 10.1007/s00253-012-3954-y] [Citation(s) in RCA: 220] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 02/06/2012] [Accepted: 02/07/2012] [Indexed: 11/24/2022]
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