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Improve Enzymatic Hydrolysis of Lignocellulosic Biomass by Modifying Lignin Structure via Sulfite Pretreatment and Using Lignin Blockers. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8100558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Even traditional pretreatments can partially remove or degrade lignin and hemicellulose from lignocellulosic biomass for enhancing its enzymatic digestibility, the remaining lignin in pretreated biomass still restricts its enzymatic hydrolysis by limiting cellulose accessibility and lignin-enzyme nonproductive interaction. Therefore, many pretreatments that can modify lignin structure in a unique way and approaches to block the lignin’s adverse impact have been proposed to directly improve the enzymatic digestibility of pretreated biomass. In this review, recent development in sulfite pretreatment that can transform the native lignin into lignosulfonate and subsequently enhance saccharification of pretreated biomass under certain conditions was summarized. In addition, we also reviewed the approaches of the addition of reactive agents to block the lignin’s reactive sites and limit the cellulase-enzyme adsorption during hydrolysis. It is our hope that this summary can provide a guideline for workers engaged in biorefining for the goal of reaching high enzymatic digestibility of lignocellulose.
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Huang C, Zhao X, Zheng Y, Lin W, Lai C, Yong Q, Ragauskas AJ, Meng X. Revealing the mechanism of surfactant-promoted enzymatic hydrolysis of dilute acid pretreated bamboo. BIORESOURCE TECHNOLOGY 2022; 360:127524. [PMID: 35764283 DOI: 10.1016/j.biortech.2022.127524] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
To improve the enzymatic digestibility of dilute acid pretreated bamboo residue (DABR), surfactants including PEG 4000 and Tween 80 were added to prevent the non-productive adsorption between residual lignin and enzyme. At the optimal loadings (e.g., 0.2 and 0.3 g surfactant/g lignin), the enzymatic digestibility of DABR improved from 29.4% to 64.6% and 61.6% for PEG 4000 and Tween 80, respectively. Furthermore, the promoting mechanism of these surfactants on enzymatic hydrolysis was investigated by real-time surface plasmon resonance (SPR) and fluorescence spectroscopy. Results from SPR analysis showed that Tween 80 outperformed PEG 4000 in terms of dissociating the irreversible cellulase adsorption onto lignin. Fluorescence quenching mechanism revealed that PEG 4000 and Tween 80 intervened the interaction between lignin and cellulase by hydrogen bonds/Van der Waals and hydrophobic action, respectively. This work provided an in-depth understanding of the mechanisms of PEG 4000 and Tween 80 on enhancing the enzymatic hydrolysis efficiency.
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Affiliation(s)
- Caoxing Huang
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xiaoxue Zhao
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Yayue Zheng
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Wenqian Lin
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Chenhuan Lai
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Qiang Yong
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, The University of Tennessee Institute of Agriculture, Knoxville, TN 37996, USA; Joint Institute for Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA.
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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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Li J, Zhang Y, Shi S, Tu M. Effect of residual extractable lignin on acetone-butanol-ethanol production in SHF and SSF processes. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:67. [PMID: 32308736 PMCID: PMC7149896 DOI: 10.1186/s13068-020-01710-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Lignin plays an important role in biochemical conversion of biomass to biofuels. A significant amount of lignin is precipitated on the surface of pretreated substrates after organosolv pretreatment. The effect of this residual lignin on enzymatic hydrolysis has been well understood, however, their effect on subsequent ABE fermentation is still unknown. RESULTS To determine the effect of residual extractable lignin on acetone-butanol-ethanol (ABE) fermentation in separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes, we compared ABE production from ethanol-washed and unwashed substrates. The ethanol organosolv pretreated loblolly pine (OPLP) was used as the substrate. It was observed that butanol production from OPLP-UW (unwashed) and OPLP-W (washed) reached 8.16 and 1.69 g/L, respectively, in SHF. The results showed that ABE production in SHF from OPLP-UW prevents an "acid crash" as compared the OPLP-W. In SSF process, the "acid crash" occurred for both OPLP-W and OPLP-UW. The inhibitory extractable lignin intensified the "acid crash" for OPLP-UW and resulted in less ABE production than OPLP-W. The addition of detoxified prehydrolysates in SSF processes shortened the fermentation time and could potentially prevent the "acid crash". CONCLUSIONS The results suggested that the residual extractable lignin in high sugar concentration could help ABE production by lowering the metabolic rate and preventing "acid crash" in SHF processes. However, it became unfavorable in SSF due to its inhibition of both enzymatic hydrolysis and ABE fermentation with low initial sugar concentration. It is essential to remove extractable lignin of substrates for ABE production in SSF processes. Also, a higher initial sugar concentration is needed to prevent the "acid crash" in SSF processes.
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Affiliation(s)
- Jing Li
- Alabama Center for Paper & Bioresource Engineering, Auburn University, Auburn, AL 36849 USA
| | - Yu Zhang
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221 USA
| | - Suan Shi
- Engineering Laboratory for AgroBiomass Recycling & Valorizing, College of Engineering, China Agricultural University, Beijing, 100083 China
| | - Maobing Tu
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221 USA
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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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Improved enzymatic hydrolysis of hardwood and cellulase stability by biomass kraft lignin-based polyoxyethylene ether. Int J Biol Macromol 2019; 136:540-546. [DOI: 10.1016/j.ijbiomac.2019.06.105] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/13/2019] [Accepted: 06/15/2019] [Indexed: 12/25/2022]
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Lai C, Jia Y, Wang J, Wang R, Zhang Q, Chen L, Shi H, Huang C, Li X, Yong Q. Co-production of xylooligosaccharides and fermentable sugars from poplar through acetic acid pretreatment followed by poly (ethylene glycol) ether assisted alkali treatment. BIORESOURCE TECHNOLOGY 2019; 288:121569. [PMID: 31181460 DOI: 10.1016/j.biortech.2019.121569] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/24/2019] [Accepted: 05/25/2019] [Indexed: 05/11/2023]
Abstract
A novel combined pretreatment process of poplar sawdust was established in this study based on the sequential acetic acid and alkali treatment with poly (ethylene glycol) diglycidyl ether (PEGDE). Effects of each treatment step on chemical composition, cellulose accessibility, and enzymatic digestibility of poplar sawdust was investigated. Acetic acid pretreatment remarkably increased cellulose accessibility while also producing a relatively high quantity of xylooligosaccharides (XOS) (37.6% of raw xylan). However, enzymatic digestibility remained low (28.3%) despite hemicellulose disruption. Post alkali treatment was next applied, leading to improvement on cellulose accessibility and enzymatic hydrolysis. Enzymatic hydrolysis was improved more significantly by successive alkali treatment with PEGDE. Its potential mechanisms attributable to enzymatic hydrolysis improvement were explored by revealing the changes to lignin properties. This work successfully demonstrated that recalcitrant waste woody biomass can be biorefined into both high-value XOS as well as relatively high yield of fermentable sugars.
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Affiliation(s)
- 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
| | - 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
| | - Jianglong Wang
- 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
| | - Ruwen Wang
- 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
| | - Qiang Zhang
- 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
| | - Liwei Chen
- 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
| | - Hao Shi
- Jiangsu Provincial Engineering Laboratory for Biomass Conversion and Process Integration, Huaiyin Institute of Technology, Huaian 223003, 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; Key Laboratory of Forestry Genetics & Biotechnology (Nanjing Forestry University), Ministry of Education, 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
| | - 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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Lai C, Yang B, He J, Huang C, Li X, Song X, Yong Q. Enhanced enzymatic digestibility of mixed wood sawdust by lignin modification with naphthol derivatives during dilute acid pretreatment. BIORESOURCE TECHNOLOGY 2018; 269:18-24. [PMID: 30145521 DOI: 10.1016/j.biortech.2018.08.086] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/19/2018] [Accepted: 08/20/2018] [Indexed: 05/20/2023]
Abstract
Effects of the addition of 2-naphthol and 2-naphthol-7-sulfonate on the dilute acid pretreatment of mixed wood sawdust were investigated, respectively. Compared to 2-naphthol, 2-naphtnol-7-sulfonate was more effective to enhance delignification and facilitate the enzymatic hydrolysis. The 72 h hydrolysis yield was improved by 47.8% for 2-naphthol-7-sulfone, while only 9.1% was observed for 2-naphthol. The surface charges, enzyme adsorption, and cellulose accessibility of dilute acid pretreated substrates with or without naphthol derivatives were examined. The improved enzymatic hydrolysis by adding 2-naphthol-7-sulfonate was ascribed to the higher negative surface charges, the lower enzyme non-productive binding, and the higher cellulose accessibility of pretreated substrates. Additionally, the HSQC NMR and 31P NMR analysis were carried out on both decomposed lignins and residual bulk lignins. It indicated that the addition of the naphthol derivatives during pretreatment could suppress the lignin repolymerization, which further mitigated the inhibition of residual lignins on enzymatic hydrolysis.
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Affiliation(s)
- Chenhuan Lai
- Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Bo Yang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Juan He
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Caoxing Huang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xin Li
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xiangyang Song
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Qiang Yong
- Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China.
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Pamidipati S, Ahmed A. Cellulase stimulation during biodegradation of lignocellulosic residues at increased biomass loading. BIOCATAL BIOTRANSFOR 2018. [DOI: 10.1080/10242422.2018.1508284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Sirisha Pamidipati
- Department of Chemical Engineering, Birla Institute of Technology and Science Pilani - Hyderabad campus, Jawahar Nagar, Shameerpet Mandal, Hyderabad, India
| | - Asma Ahmed
- Department of Chemical Engineering, Birla Institute of Technology and Science Pilani - Hyderabad campus, Jawahar Nagar, Shameerpet Mandal, Hyderabad, India
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