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Fan Z, Xia W, Zhang H, Peng D, Han S, Wu X, Sun F. Evaluating the mechanism of soybean meal protein for boosting the laccase-catalyzed of thymol onto lignosulfonate via restraining non-specific adsorption. Int J Biol Macromol 2024; 263:130367. [PMID: 38401588 DOI: 10.1016/j.ijbiomac.2024.130367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 02/26/2024]
Abstract
The control of laccase-catalyzed efficiency often relies on the utilization of modifying enzyme molecules and shielding agents. However, their elevated costs or carcinogenicity led to the inability for large-scale application. To address this concern, we found that a low-cost protein from soybean meal can reduce lignin's ineffective adsorption onto enzymes for improving the efficiency of thymol grafting to lignosulfonate. The results demonstrated that by adding 0.5 mg/mL of additional soybean meal protein, the thymol reaction ratio of the modified lignosulfonate (L-0.5 S) significantly boosted from 18.1 % to 35.0 %, with the minimal inhibitory concentrations of the L-0.5 S against Aspergillus niger dramatically improved from 12.5 mg/mL to 3.1 mg/mL. Multiple characterization methods were employed to better understand the benefit of the modification under the addition of the soybean meal protein. The CO and R1-O group content increased from 20.5 % to 37.8 % and from 65.1 % to 75.5 %, respectively. The proposed potential reaction mechanism was further substantiated by the physicochemical properties. The incorporation of soybean meal effectively mitigated the non-specific adsorption of lignosulfonate, resulting in a reduction of the surface area of lignin from 235.0 to 139.2 m2/g. The utilization of soybean meal as a cost-effective and efficient shielding agent significantly enhanced the efficiency of subsequent enzyme catalysis. Consequently, the application of soybean meal in commercial enzyme catalysis holds considerable appeal and amplifies the relevance of this study in preservative industries.
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Affiliation(s)
- Zhiwei Fan
- School of Chemical and Materials Engineering, National Engineering & Technology Research Center of Wood-Based Resources Comprehensive Utilization, Zhejiang A & F University, Hangzhou 311300, People's Republic of China
| | - Weichao Xia
- School of Chemical and Materials Engineering, National Engineering & Technology Research Center of Wood-Based Resources Comprehensive Utilization, Zhejiang A & F University, Hangzhou 311300, People's Republic of China
| | - Huili Zhang
- School of Chemical and Materials Engineering, National Engineering & Technology Research Center of Wood-Based Resources Comprehensive Utilization, Zhejiang A & F University, Hangzhou 311300, People's Republic of China
| | - Dandan Peng
- School of Chemical and Materials Engineering, National Engineering & Technology Research Center of Wood-Based Resources Comprehensive Utilization, Zhejiang A & F University, Hangzhou 311300, People's Republic of China
| | - Shuaibo Han
- School of Chemical and Materials Engineering, National Engineering & Technology Research Center of Wood-Based Resources Comprehensive Utilization, Zhejiang A & F University, Hangzhou 311300, People's Republic of China; Microbes and Insects Control Institute of Bio-based Materials, Zhejiang A&F University, Hangzhou 311300, People's Republic of China.
| | - Xinxing Wu
- School of Chemical and Materials Engineering, National Engineering & Technology Research Center of Wood-Based Resources Comprehensive Utilization, Zhejiang A & F University, Hangzhou 311300, People's Republic of China; Microbes and Insects Control Institute of Bio-based Materials, Zhejiang A&F University, Hangzhou 311300, People's Republic of China.
| | - Fangli Sun
- School of Chemical and Materials Engineering, National Engineering & Technology Research Center of Wood-Based Resources Comprehensive Utilization, Zhejiang A & F University, Hangzhou 311300, People's Republic of China; Microbes and Insects Control Institute of Bio-based Materials, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
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Borisova AS, Virkkala T, Pylkkänen R, Kellock M, Mohammadi P. Toughening brittle kraft lignin coating on mismatched substrate with spider Silk-Inspired protein as an interfacial modulator. J Colloid Interface Sci 2024; 655:789-799. [PMID: 37976752 DOI: 10.1016/j.jcis.2023.11.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/03/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023]
Abstract
Current production of functional coatings majorly relies on petrochemical formulations. While they have provided substantial benefits, their fabrication processes as well as their disposal created widespread ecological catastrophes. Thus, there is a pressing demand and calls for a radical transformation to develop sustainable solutions by using renewable building blocks. Herein, we report on a novel coating formulation by combining largely undervalued kraft lignin from the forest industry, with genetically engineered and recombinantly produced spider silk-inspired protein through the industrial biotechnology platform. Unmodified kraft lignin was used as the main bulk component in the coating given its abundance and low cost. The nanometer-thin spider silk-inspired protein (SSIP) was used as a primary layer exhibiting dual functionalities: (i) modulating the mechanical properties of inherently brittle kraft lignin, (ii) substantially increasing the interfacial binding of kraft lignin to the underlying rigid silica substrate with the mismatched physicochemical properties. Our findings demonstrate how synergistic interplay components could result in scalable and durable functional coatings which could potentially be used in various medical and industrial applications in the future.
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Affiliation(s)
- Anna S Borisova
- VTT Technical Research Centre of Finland, FI-02044 VTT, Finland.
| | - Tuuli Virkkala
- VTT Technical Research Centre of Finland, FI-02044 VTT, Finland
| | - Robert Pylkkänen
- VTT Technical Research Centre of Finland, FI-02044 VTT, Finland; Centre of Excellence in Life-Inspired Hybrid Materials (LIBER), Aalto University, 00076 Aalto, Finland
| | - Miriam Kellock
- VTT Technical Research Centre of Finland, FI-02044 VTT, Finland
| | - Pezhman Mohammadi
- VTT Technical Research Centre of Finland, FI-02044 VTT, Finland; Centre of Excellence in Life-Inspired Hybrid Materials (LIBER), Aalto University, 00076 Aalto, Finland.
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Haviland ZK, Nong D, Zexer N, Tien M, Anderson CT, Hancock WO. Lignin impairs Cel7A degradation of in vitro lignified cellulose by impeding enzyme movement and not by acting as a sink. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:7. [PMID: 38243336 PMCID: PMC10799419 DOI: 10.1186/s13068-023-02456-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 12/30/2023] [Indexed: 01/21/2024]
Abstract
BACKGROUND Cellulose degradation by cellulases has been studied for decades due to the potential of using lignocellulosic biomass as a sustainable source of bioethanol. In plant cell walls, cellulose is bonded together and strengthened by the polyphenolic polymer, lignin. Because lignin is tightly linked to cellulose and is not digestible by cellulases, is thought to play a dominant role in limiting the efficient enzymatic degradation of plant biomass. Removal of lignin via pretreatments currently limits the cost-efficient production of ethanol from cellulose, motivating the need for a better understanding of how lignin inhibits cellulase-catalyzed degradation of lignocellulose. Work to date using bulk assays has suggested three possible inhibition mechanisms: lignin blocks access of the enzyme to cellulose, lignin impedes progress of the enzyme along cellulose, or lignin binds cellulases directly and acts as a sink. RESULTS We used single-molecule fluorescence microscopy to investigate the nanoscale dynamics of Cel7A from Trichoderma reesei, as it binds to and moves along purified bacterial cellulose in vitro. Lignified cellulose was generated by polymerizing coniferyl alcohol onto purified bacterial cellulose, and the degree of lignin incorporation into the cellulose meshwork was analyzed by optical and electron microscopy. We found that Cel7A preferentially bound to regions of cellulose where lignin was absent, and that in regions of high lignin density, Cel7A binding was inhibited. With increasing degrees of lignification, there was a decrease in the fraction of Cel7A that moved along cellulose rather than statically binding. Furthermore, with increasing lignification, the velocity of processive Cel7A movement decreased, as did the distance that individual Cel7A molecules moved during processive runs. CONCLUSIONS In an in vitro system that mimics lignified cellulose in plant cell walls, lignin did not act as a sink to sequester Cel7A and prevent it from interacting with cellulose. Instead, lignin both blocked access of Cel7A to cellulose and impeded the processive movement of Cel7A along cellulose. This work implies that strategies for improving biofuel production efficiency should target weakening interactions between lignin and cellulose surface, and further suggest that nonspecific adsorption of Cel7A to lignin is likely not a dominant mechanism of inhibition.
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Affiliation(s)
- Zachary K Haviland
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Daguan Nong
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Nerya Zexer
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Ming Tien
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Charles T Anderson
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - William O Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA.
- Department of Chemistry, Pennsylvania State University, University Park, PA, USA.
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Lu X, Li X, Zhao J. Improving enzymatic efficiency of β-glucosidases in cellulase system by altering its binding behavior to the insoluble substrate during bioconversion of lignocellulose. BIORESOURCE TECHNOLOGY 2024; 391:129974. [PMID: 37939741 DOI: 10.1016/j.biortech.2023.129974] [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: 09/12/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/10/2023]
Abstract
The enzymatic efficiency of β-glucosidases is influenced by their binding behavior onto insoluble substrates (cellulose and lignin) during bioconversion of lignocellulose. This study suggested that the Bgl3 protein (Aspergillus fumigatus) showed strong adsorption affinity to lignin and the Bgl1 protein (Penicillium oxalicum) tended to adsorb to cellulose. It indicated that the various surface properties of the fibronectin type Ш-like domain (FnIII) led to different binding properties of β-glucosidases by investigating their binding mechanism. By engineering β-glucosidases' FnIII domain, Bgl3-1 and Bgl1-3 were constructed, which both showed lower binding capacities to insoluble substrates. As well as for Bgl1-3, its sensitivity to the phenolic component was also eased. Based on that, the reconstructed protein showed high catalytic efficiency during the enzymatic hydrolysis of corn stover by effectively transforming cellobiose to glucose. Thus, this study provided a new strategy to engineer β-glucosidases to enhance their performance in the cellulase system.
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Affiliation(s)
- Xianqin Lu
- State Key Laboratory of Microbial Technology, Shandong University, No.72, Binhai Road, Qingdao 266237, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, No.72, Binhai Road, Qingdao 266237, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, No.72, Binhai Road, Qingdao 266237, China.
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Xu L, Wang J, Zhang A, Pang Y, Yang D, Lou H, Qiu X. Unveiling the role of long-range and short-range forces in the non-productive adsorption between lignin and cellulases at different temperatures. J Colloid Interface Sci 2023; 647:318-330. [PMID: 37262994 DOI: 10.1016/j.jcis.2023.05.152] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 04/04/2023] [Accepted: 05/23/2023] [Indexed: 06/03/2023]
Abstract
Quantitatively understanding of interaction mechanism between lignin and cellulases is essential for the efficient improvement of lignocellulose enzymatic hydrolysis. However, the individual contribution of multiple forces between lignin and cellulases to the non-productive adsorption of enzymes still remains deeply ambiguous, especially in situations of near enzymatic hydrolysis temperatures. Herein, atomic force microscopy (AFM) and computational simulations were utilized to quantitatively analyze the intermolecular forces between lignin and enzyme at 25 °C and 40 °C. Our results unveiled that an increase in temperature obviously improved adsorption capacity and total intermolecular forces between lignin and cellulases. This positive relationship mainly comes from the increase in the decay length of hydrophobic forces for lignin-cellulases when temperature increases. Different from the hydrophobic interaction which provides long-range part of attractions, van der Waals forces dominate the intermolecular force only at approaches < 2 nm. On the other hand, electrostatic forces exhibited repulsive effects, and its intensity and distance were limited due to the low surface potential of cellulases. Short-range forces including hydrogen bonding (main) and π-π stacking (minor) stabilize the non-specific binding of enzymes to lignin, but increasing temperature reduces hydrogen bond number. Therefore, the relative contribution of long-range forces increased markedly at higher temperatures, which benefits protein capture and brings lignin and cellulase close together. Finally, the structure-activity relationships between lignin physicochemical properties and its inhibitory effect to enzymes indicated that hydrophobic interactions, hydrogen bonding, and steric effects drive the final adsorption capacity and glucose yields. This work provides quantitative and basic insights into the mechanism of lignin-cellulase interfacial interactions and guides design of saccharification enhancement approaches.
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Affiliation(s)
- Li Xu
- Guangdong Provincial Key Lab of Green Chemical Product Technology, State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Jingyu Wang
- Guangdong Provincial Key Lab of Green Chemical Product Technology, State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Aiting Zhang
- Guangdong Provincial Key Lab of Green Chemical Product Technology, State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Yuxia Pang
- Guangdong Provincial Key Lab of Green Chemical Product Technology, State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
| | - Dongjie Yang
- Guangdong Provincial Key Lab of Green Chemical Product Technology, State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Hongming Lou
- Guangdong Provincial Key Lab of Green Chemical Product Technology, State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
| | - Xueqing Qiu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China
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6
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Chaudhari YB, Várnai A, Sørlie M, Horn SJ, Eijsink VGH. Engineering cellulases for conversion of lignocellulosic biomass. Protein Eng Des Sel 2023; 36:gzad002. [PMID: 36892404 PMCID: PMC10394125 DOI: 10.1093/protein/gzad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/13/2023] [Accepted: 02/24/2023] [Indexed: 03/10/2023] Open
Abstract
Lignocellulosic biomass is a renewable source of energy, chemicals and materials. Many applications of this resource require the depolymerization of one or more of its polymeric constituents. Efficient enzymatic depolymerization of cellulose to glucose by cellulases and accessory enzymes such as lytic polysaccharide monooxygenases is a prerequisite for economically viable exploitation of this biomass. Microbes produce a remarkably diverse range of cellulases, which consist of glycoside hydrolase (GH) catalytic domains and, although not in all cases, substrate-binding carbohydrate-binding modules (CBMs). As enzymes are a considerable cost factor, there is great interest in finding or engineering improved and robust cellulases, with higher activity and stability, easy expression, and minimal product inhibition. This review addresses relevant engineering targets for cellulases, discusses a few notable cellulase engineering studies of the past decades and provides an overview of recent work in the field.
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Affiliation(s)
- Yogesh B Chaudhari
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU-Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
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Liu J, Wu J, Lu Y, Zhang H, Hua Q, Bi R, Rojas O, Renneckar S, Fan S, Xiao Z, Saddler J. The pre-addition of "blocking" proteins decreases subsequent cellulase adsorption to lignin and enhances cellulose hydrolysis. BIORESOURCE TECHNOLOGY 2023; 367:128276. [PMID: 36347476 DOI: 10.1016/j.biortech.2022.128276] [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: 09/30/2022] [Revised: 10/31/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
The pre-adsorption of non-catalytic/blocking proteins onto the lignin component of pretreated biomass has been shown to significantly increase the effectiveness of subsequent enzyme-mediated hydrolysis of the cellulose by limiting non-productive enzyme adsorption. Layer-by-layer adsorption of non-catalytic proteins and enzymes onto lignin was monitored using Quartz Crystal Micro balancing combined with Dissipation monitoring (QCM-D) and conventional protein adsorption. These methods were used to assess the interaction between soft/hardwood lignins, cellulases and the three non-catalytic proteins BSA, lysozyme and ovalbumin. The QCM-D analysis showed higher adsorption rates for all of the non-catalytic proteins onto the lignin films as compared to cellulases. This suggested that the "blocking" proteins would preferentially adsorb to the lignin rather than the enzymes. Pre-incubation of the lignin films with blocking proteins resulted in reduced adsorption of cellulases onto the lignin, significantly enhancing cellulose hydrolysis.
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Affiliation(s)
- Jingyun Liu
- School of Chemical Engineering, Sichuan University, 610065 Chengdu, China; Forest Product 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 Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Yi Lu
- Bioproducts Institute, Department of Chemical and Biological Engineering, Department of Chemistry and Department of Wood Science, University of British Columbia, 2385 East Mall, Vancouver, BC V6T 1Z3, Canada
| | - Huaiyu Zhang
- Advanced Renewable Materials Lab, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Qi Hua
- Advanced Renewable Materials Lab, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Ran Bi
- Bioproducts Institute, Department of Chemical and Biological Engineering, Department of Chemistry and Department of Wood Science, University of British Columbia, 2385 East Mall, Vancouver, BC V6T 1Z3, Canada
| | - Orlando Rojas
- Bioproducts Institute, Department of Chemical and Biological Engineering, Department of Chemistry and Department of Wood Science, University of British Columbia, 2385 East Mall, Vancouver, BC V6T 1Z3, Canada
| | - Scott Renneckar
- Advanced Renewable Materials Lab, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Senqing Fan
- School of Chemical Engineering, Sichuan University, 610065 Chengdu, China
| | - Zeyi Xiao
- School of Chemical Engineering, Sichuan University, 610065 Chengdu, China
| | - 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.
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8
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Kellock M, Rahikainen J, Borisova AS, Voutilainen S, Koivula A, Kruus K, Marjamaa K. Inhibitory effect of lignin on the hydrolysis of xylan by thermophilic and thermolabile GH11 xylanases. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:49. [PMID: 35568899 PMCID: PMC9107766 DOI: 10.1186/s13068-022-02148-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/30/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Enzymatic hydrolysis of lignocellulosic biomass into platform sugars can be enhanced by the addition of accessory enzymes, such as xylanases. Lignin from steam pretreated biomasses is known to inhibit enzymes by non-productively binding enzymes and limiting access to cellulose. The effect of enzymatically isolated lignin on the hydrolysis of xylan by four glycoside hydrolase (GH) family 11 xylanases was studied. Two xylanases from the mesophilic Trichoderma reesei, TrXyn1, TrXyn2, and two forms of a thermostable metagenomic xylanase Xyl40 were compared.
Results
Lignin isolated from steam pretreated spruce decreased the hydrolysis yields of xylan for all the xylanases at 40 and 50 °C. At elevated hydrolysis temperature of 50 °C, the least thermostable xylanase TrXyn1 was most inhibited by lignin and the most thermostable xylanase, the catalytic domain (CD) of Xyl40, was least inhibited by lignin. Enzyme activity and binding to lignin were studied after incubation of the xylanases with lignin for up to 24 h at 40 °C. All the studied xylanases bound to lignin, but the thermostable xylanases retained 22–39% of activity on the lignin surface for 24 h, whereas the mesophilic T. reesei xylanases become inactive. Removing of N-glycans from the catalytic domain of Xyl40 increased lignin inhibition in hydrolysis of xylan when compared to the glycosylated form. By comparing the 3D structures of these xylanases, features contributing to the increased thermal stability of Xyl40 were identified.
Conclusions
High thermal stability of xylanases Xyl40 and Xyl40-CD enabled the enzymes to remain partially active on the lignin surface. N-glycosylation of the catalytic domain of Xyl40 increased the lignin tolerance of the enzyme. Thermostability of Xyl40 was most likely contributed by a disulphide bond and salt bridge in the N-terminal and α-helix regions.
Graphical Abstract
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9
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Effects of Lipase and Xylanase Pretreatment on the Structure and Pulping Properties of Wheat Straw. Polymers (Basel) 2022; 14:polym14235129. [PMID: 36501524 PMCID: PMC9735998 DOI: 10.3390/polym14235129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/19/2022] [Accepted: 11/22/2022] [Indexed: 11/26/2022] Open
Abstract
Based on the reduction of environmental pollution, a biological enzyme assisted alkali-oxygen pulping method was explored to improve the delignification efficiency and fiber accessibility of wheat straw and improve the properties of wheat straw pulp. In this paper, lipase and xylanase were used to pretreat wheat straw and the effects of different enzyme types and enzyme dosage on the microstructure and pulp properties of wheat straw were investigated and experimented. The results showed that the lipase can remove fat and wax on the surface of wheat straw, while xylanase degraded the hemicellulose components, such as xylan, of wheat straw fiber, destroyed the structure of the lignin-carbohydrate complex, increasing lignin removal as a result and enhancing the impregnating, diffusion and penetration of alkali. Compared with wheat straw without enzyme pretreatment, the skeleton of wheat straw pretreated by enzyme became looser, the internal cavity appeared and the wall cavity became thin and transparent. The fines decreased obviously and the length of fibers increased. After combined pretreatment with lipase (15 U·g-1) and xylanase (15 U·g-1), the pulping performance of wheat straw was improved and the tensile index (97.37 N·m·g-1), brightness (40.9% ISO) and yield (58.10%) of the pulp increased by 12.9%, 19.9% and 9.9%, respectively. It can be seen that enzyme pretreatment is a green and effective approach to improving the alkali-oxygen pulping performance of wheat straw.
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10
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Wang Z, Fan C, Zheng X, Jin Z, Bei K, Zhao M, Kong H. Roles of Surfactants in Oriented Immobilization of Cellulase on Nanocarriers and Multiphase Hydrolysis System. Front Chem 2022; 10:884398. [PMID: 35402378 PMCID: PMC8983819 DOI: 10.3389/fchem.2022.884398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/09/2022] [Indexed: 11/16/2022] Open
Abstract
Surfactants, especially non-ionic surfactants, play an important role in the preparation of nanocarriers and can also promote the enzymatic hydrolysis of lignocellulose. A broad overview of the current status of surfactants on the immobilization of cellulase is provided in this review. In addition, the restricting factors in cellulase immobilization in the complex multiphase hydrolysis system are discussed, including the carrier structure characteristics, solid-solid contact obstacles, external diffusion resistance, limited recycling frequency, and nonproductive combination of enzyme active centers. Furthermore, promising prospects of cellulase-oriented immobilization are proposed, including the hydrophilic-hydrophobic interaction of surfactants and cellulase in the oil-water reaction system, the reversed micelle system of surfactants, and the possible oriented immobilization mechanism.
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Affiliation(s)
- Zhiquan Wang
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Chunzhen Fan
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Xiangyong Zheng
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Zhan Jin
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Ke Bei
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Min Zhao
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Hainan Kong
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
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11
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Banu Jamaldheen S, Kurade MB, Basak B, Yoo CG, Oh KK, Jeon BH, Kim TH. A review on physico-chemical delignification as a pretreatment of lignocellulosic biomass for enhanced bioconversion. BIORESOURCE TECHNOLOGY 2022; 346:126591. [PMID: 34929325 DOI: 10.1016/j.biortech.2021.126591] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Effective pretreatment of lignocellulosic biomass (LCB) is one of the most important steps in biorefinery, ensuring the quality and commercial viability of the overall bioprocess. Lignin recalcitrance in LCB is a major bottleneck in biological conversion as the polymerization of lignin with hemicellulose hinders enzyme accessibility and further bioconversion to fuels and chemicals. Therefore, there is a need to delignify LCB to ease further bioprocessing. The efficiency of delignification, quality and quantity of the desired products, and generation of inhibitors depend upon the type of pretreatment employed. This review summarizes different single and integrated physicochemical pretreatments for delignification. Additionally, conditions required for effective delignification and the advantages and drawbacks of each method were evaluated. Advances in overcoming the recalcitrance of residual lignin to saccharification and the methods to recover lignin after delignification are also discussed. Efficient lignin recovery and valorization strategies provide an avenue for the sustainable lignocellulose biorefinery.
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Affiliation(s)
- Sumitha Banu Jamaldheen
- Department of Materials Science and Chemical Engineering, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Mayur B Kurade
- Department of Earth Resources and Environmental Engineering, Hanyang University, 222-Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Bikram Basak
- Department of Earth Resources and Environmental Engineering, Hanyang University, 222-Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Chang Geun Yoo
- Department of Chemical Engineering, State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Kyeong Keun Oh
- Department of Chemical Engineering, Dankook University, Youngin 16890, Gyeonggi-do, Republic of Korea
| | - Byong-Hun Jeon
- Department of Earth Resources and Environmental Engineering, Hanyang University, 222-Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Tae Hyun Kim
- Department of Materials Science and Chemical Engineering, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea.
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Monclaro AV, Gorgulho Silva CDO, Gomes HAR, Moreira LRDS, Filho EXF. The enzyme interactome concept in filamentous fungi linked to biomass valorization. BIORESOURCE TECHNOLOGY 2022; 344:126200. [PMID: 34710591 DOI: 10.1016/j.biortech.2021.126200] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 05/15/2023]
Abstract
Biomass represents an abundant and inexpensive source of sugars and aromatic compounds that can be used as raw materials for conversion into value-added bioproducts. Filamentous fungi are sources of plant cell wall degrading enzymes in nature. Understanding the interactions between enzymes is crucial for optimizing biomass degradation processes. Herein, the concept of the interactome is presented as a holistic approach that depicts the interactions among enzymes, substrates, metabolites, and inhibitors. The interactome encompasses several stages of biomass degradation, starting with the sensing of the substrate and the subsequent synthesis of hydrolytic and oxidative enzymes (fungus-substrate interaction). Enzyme-enzyme interactions are exemplified in the complex processes of lignocellulosic biomass degradation. The enzyme-substrate-metabolite-inhibitor interaction also provides a better understanding of biomass conversion, allowing bioproduct production from recalcitrant agro-industrial residues, thus bringing greater value to residual biomass. Finally, technological applications are presented for optimizing the interactome at various levels.
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Affiliation(s)
- Antonielle Vieira Monclaro
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Center for Advanced Process Technology and Urban Resource Efficiency (CAPTURE), Frieda Saeysstraat, 9052 Ghent, Belgium
| | - Caio de Oliveira Gorgulho Silva
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway; Protein Chemistry and Enzyme Technology Section, DTU Bioengineering, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Helder Andrey Rocha Gomes
- Health Science School, University Center of the Federal District (UDF), DF, Brasília 70390045, Brazil
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Neis A, da Silva Pinto L. Glycosyl hydrolases family 5, subfamily 5: Relevance and structural insights for designing improved biomass degrading cocktails. Int J Biol Macromol 2021; 193:980-995. [PMID: 34666133 DOI: 10.1016/j.ijbiomac.2021.10.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
Endoglucanases are carbohydrate-degrading enzymes widely used for bioethanol production as part of the enzymatic cocktail. However, family 5 subfamily 5 (GH5_5) endoglucanases are still poorly explored in depth. The Trichoderma reesei representative is the most studied enzyme, presenting catalytic activity in acidic media and mild temperature conditions. Though biochemically similar, its modular structure and synergy with other components vary greatly compared to other GH5_5 members and there is still a lack of specific studies regarding their interaction with other cellulases and application on novel and better mixtures. In this regard, the threedimensional structure elucidation is a highly valuable tool to both uncover basic catalytic mechanisms and implement engineering techniques, proved by the high success rate GH5_5 endoglucanases show. GH5_5 enzymes must be carefully evaluated to fully uncover their potential in biomass-degrading cocktails: the optimal industrial conditions, synergy with other cellulases, structural studies, and enzyme engineering approaches. We aimed to provide the current understanding of these main topics, collecting all available information about characterized GH5_5 endoglucanases function, structure, and bench experiments, in order to suggest future directions to a better application of these enzymes in the industry.
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Affiliation(s)
- Alessandra Neis
- Laboratório de Bioinformática e Proteômica (BioPro Lab), Centro de Desenvolvimento Tecnológico, Campus Universitário, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Caixa Postal 96010-900, Brazil.
| | - Luciano da Silva Pinto
- Laboratório de Bioinformática e Proteômica (BioPro Lab), Centro de Desenvolvimento Tecnológico, Campus Universitário, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Caixa Postal 96010-900, Brazil.
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14
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Fungal cellulases: protein engineering and post-translational modifications. Appl Microbiol Biotechnol 2021; 106:1-24. [PMID: 34889986 DOI: 10.1007/s00253-021-11723-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 12/18/2022]
Abstract
Enzymatic degradation of lignocelluloses into fermentable sugars to produce biofuels and other biomaterials is critical for environmentally sustainable development and energy resource supply. However, there are problems in enzymatic cellulose hydrolysis, such as the complex cellulase composition, low degradation efficiency, high production cost, and post-translational modifications (PTMs), all of which are closely related to specific characteristics of cellulases that remain unclear. These problems hinder the practical application of cellulases. Due to the rapid development of computer technology in recent years, computer-aided protein engineering is being widely used, which also brings new opportunities for the development of cellulases. Especially in recent years, a large number of studies have reported on the application of computer-aided protein engineering in the development of cellulases; however, these articles have not been systematically reviewed. This article focused on the aspect of protein engineering and PTMs of fungal cellulases. In this manuscript, the latest literatures and the distribution of potential sites of cellulases for engineering have been systematically summarized, which provide reference for further improvement of cellulase properties. KEY POINTS: •Rational design based on virtual mutagenesis can improve cellulase properties. •Modifying protein side chains and glycans helps obtain superior cellulases. •N-terminal glutamine-pyroglutamate conversion stabilizes fungal cellulases.
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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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16
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Xiong Q, Qiao J, Wang M, Li S, Li X. Carboxylated and quaternized lignin enhanced enzymatic hydrolysis of lignocellulose treated by p-toluenesulfonic acid due to improving enzyme activity. BIORESOURCE TECHNOLOGY 2021; 337:125465. [PMID: 34320745 DOI: 10.1016/j.biortech.2021.125465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/20/2021] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
Modificated lignins can affect enzymatic hydrolysis efficiency (EHE) because of changing physicochemical properties of lignin. In this study, carboxylated and quaternized lignin (CQL) and hydroxymethylated lignin (HML) were prepared to explore the effect of lignin modification on cellulase adsorption and EHE of p-toluenesulfonic acid treated corn stover (PCS). The results showed that CQL enhanced EHE of PCS due to the higher β-glucosidase (β-GL) activity, resulting from the formation of CQL-β-GL complexes with a lower binding free energy and the improvement of β-GL conformation made by the binding of CQL and β-GL. However, the drop in EHE due to the addition of HML was consequent on β-GL deactivation that was because the binding site of HML and β-GL overlapped with the carbohydrate binding domain of β-GL, causing the decrease in β-GL activity compared with CQL. This study would help deeply elucidate the effect of modified lignins on EHE and cellulase adsorption.
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Affiliation(s)
- Qiang Xiong
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China; SDIC Biotech Investment Co., Ltd., Beijing 100034, China
| | - Jie Qiao
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, No. 2 Xuelin Road, Nanjing 210097, China
| | - Minghui Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, No. 2 Xuelin Road, Nanjing 210097, China
| | - Shuang Li
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Xiujuan Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, No. 2 Xuelin Road, Nanjing 210097, China.
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Wang Y, Yang Y, Qu Y, Zhang J. Selective removal of lignin with sodium chlorite to improve the quality and antioxidant activity of xylo-oligosaccharides from lignocellulosic biomass. BIORESOURCE TECHNOLOGY 2021; 337:125506. [PMID: 34320775 DOI: 10.1016/j.biortech.2021.125506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
As a key anti-degradation barrier that restricts the biotransformation of lignocellulose, the presence of lignin usually severely affects the quality of the extracted xylo-oligosaccharides (XOS). Herein, this study proposed a practical route to improve the quality and antioxidant activity of XOS extracted from lignocellulosic biomass via selective removal of lignin. The highest delignification of 92.6% was successfully achieved with 8% sodium chlorite at 75°C for 2 h. An ideal hemicellulose sample with a purity of 86.1% was obtained by selective removal of lignin. A high-quality XOS sample with a purity of 96.3%, a yield of 77.4%, and a color value of 814 was obtained by separating and purifying the enzymatic hydrolysate. Antioxidant activity assay showed that the highest radical scavenging activity of XOS was 87.3%. Importantly, this study provide a feasible and effective route for the lignocellulosic biomass utilization strategy based on the selective removal of lignin.
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Affiliation(s)
- Yuehai Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; School of Chemical and Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yongqing Yang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; School of Chemical and Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yongshui Qu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Zhang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
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18
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Cellulase immobilized by sodium alginate-polyethylene glycol-chitosan for hydrolysis enhancement of microcrystalline cellulose. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Pihlajaniemi V, Kallioinen A, Sipponen MH, Nyyssölä A. Modeling and optimization of polyethylene glycol (PEG) addition for cost-efficient enzymatic hydrolysis of lignocellulose. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2020.107894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Guo R, Zheng X, Wang Y, Yang Y, Ma Y, Zou D, Liu Y. Optimization of Cellulase Immobilization with Sodium Alginate-Polyethylene for Enhancement of Enzymatic Hydrolysis of Microcrystalline Cellulose Using Response Surface Methodology. Appl Biochem Biotechnol 2021; 193:2043-2060. [PMID: 33544365 DOI: 10.1007/s12010-021-03517-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/27/2021] [Indexed: 10/22/2022]
Abstract
A novel method of immobilizing cellulase on sodium alginate (SA)-polyethylene glycol (PEG) enabled the cellulase to be used repeatedly. The matrix of the immobilized cellulase was detected and characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. In comparison with SA-immobilized cellulase, the relative enzyme activity and immobilization rate increased by 25% and 18%, respectively. The application range of the immobilized enzyme in terms of temperature and pH was larger than that of the free enzyme, and its thermal stability increased. The immobilized enzyme was used in enzymatic hydrolysis, in which MCC was used as the substrate. The optimal conditions for enzymatic hydrolysis were as follows: the dosage of SA-PEG-immobilized cellulase was 3.55 g/g total solids of the substrate, the concentration of the substrate was 13.16%, and the pH was 5.11. In comparison with the yield of reducing sugars in the first round of hydrolysis of MCC by SA-immobilized cellulase, the yield in the hydrolysis of MCC by SA-PEG-immobilized cellulase increased by 133%. After five cycles of repeated use, the total yield of reducing sugars when MCC was hydrolyzed by SA-PEG-immobilized cellulase was similar to that achieved with free cellulase. In comparison with the free enzyme, the highest yield when the immobilized enzyme was used was 22.68%. Therefore, the immobilized cellulase exhibited high performance in enzymatic hydrolysis.
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Affiliation(s)
- Rongxin Guo
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Xusheng Zheng
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yang Wang
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yiwen Yang
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yifang Ma
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Dexun Zou
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yanping Liu
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
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Zhou Z, Ju X, Chen J, Wang R, Zhong Y, Li L. Charge-oriented strategies of tunable substrate affinity based on cellulase and biomass for improving in situ saccharification: A review. BIORESOURCE TECHNOLOGY 2021; 319:124159. [PMID: 33010717 DOI: 10.1016/j.biortech.2020.124159] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
The intrinsic recalcitrance of lignocellulosic biomass makes it resistant to enzymatic hydrolysis. The electron-rich surface of the lignin and cellulose-alike structure of hemicellulose competitively absorb the cellulase. Thus, modifying the surface charge on biomass components to alter cellulase affinity is an urgent requisite. Developing charge tunable cellulase will alter substrate affinity. Also, charge-based immobilization generates controllable substrate affinity. Within immobilized cellulase involved in situ biomass saccharification, charge effects made a crucial contribution. In addition to affecting the interaction between immobilized cellulase and biomass, charge exerts an impact on cellulase to immobilize the materials, further investigation is essential. This study aims to review the charge effects on the cellulase affinity in biomass saccharification, strategies of charge tunable cellulase, and immobilized cellulase, thereby explaining the role of electrostatic interaction. In terms of electrostatic behavior, the pathways and plans to improve in situ biomass saccharification seem to be promising.
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Affiliation(s)
- Zheng Zhou
- College of Chemistry and Life Science, Suzhou University of Science and Technology, Suzhou 215009, PR China
| | - Xin Ju
- College of Chemistry and Life Science, Suzhou University of Science and Technology, Suzhou 215009, PR China
| | - Jiajia Chen
- College of Chemistry and Life Science, Suzhou University of Science and Technology, Suzhou 215009, PR China
| | - Rong Wang
- College of Chemistry and Life Science, Suzhou University of Science and Technology, Suzhou 215009, PR China
| | - Yuqing Zhong
- College of Chemistry and Life Science, Suzhou University of Science and Technology, Suzhou 215009, PR China
| | - Liangzhi Li
- College of Chemistry and Life Science, Suzhou University of Science and Technology, Suzhou 215009, PR China.
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Vishnu Prasad J, Sahoo TK, Naveen S, Jayaraman G. Evolutionary engineering of Lactobacillus bulgaricus reduces enzyme usage and enhances conversion of lignocellulosics to D-lactic acid by simultaneous saccharification and fermentation. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:171. [PMID: 33088341 PMCID: PMC7566127 DOI: 10.1186/s13068-020-01812-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 10/06/2020] [Indexed: 05/31/2023]
Abstract
BACKGROUND Simultaneous saccharification and fermentation (SSF) of pre-treated lignocellulosics to biofuels and other platform chemicals has long been a promising alternative to separate hydrolysis and fermentation processes. However, the disparity between the optimum conditions (temperature, pH) for fermentation and enzyme hydrolysis leads to execution of the SSF process at sub-optimal conditions, which can affect the rate of hydrolysis and cellulose conversion. The fermentation conditions could be synchronized with hydrolysis optima by carrying out the SSF at a higher temperature, but this would require a thermo-tolerant organism. Economically viable production of platform chemicals from lignocellulosic biomass (LCB) has long been stymied because of the significantly higher cost of hydrolytic enzymes. The major objective of this work is to develop an SSF strategy for D-lactic acid (D-LA) production by a thermo-tolerant organism, in which the enzyme loading could significantly be reduced without compromising on the overall conversion. RESULTS A thermo-tolerant strain of Lactobacillus bulgaricus was developed by adaptive laboratory evolution (ALE) which enabled the SSF to be performed at 45 °C with reduced enzyme usage. Despite the reduction of enzyme loading from 15 Filter Paper Unit/gLCB (FPU/gLCB) to 5 FPU/gLCB, we could still achieve ~ 8% higher cellulose to D-LA conversion in batch SSF, in comparison to the conversion by separate enzymatic hydrolysis and fermentation processes at 45 °C and pH 5.5. Extending the batch SSF to SSF with pulse-feeding of 5% pre-treated biomass and 5 FPU/gLCB, at 12-h intervals (36th-96th h), resulted in a titer of 108 g/L D-LA and 60% conversion of cellulose to D-LA. This is one among the highest reported D-LA titers achieved from LCB. CONCLUSIONS We have demonstrated that the SSF strategy, in conjunction with evolutionary engineering, could drastically reduce enzyme requirement and be the way forward for economical production of platform chemicals from lignocellulosics. We have shown that fed-batch SSF processes, designed with multiple pulse-feedings of the pre-treated biomass and enzyme, can be an effective way of enhancing the product concentrations.
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Affiliation(s)
- J. Vishnu Prasad
- Bioprocess and Metabolic Engineering Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600036 India
| | - Tridweep K. Sahoo
- Bioprocess and Metabolic Engineering Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600036 India
| | - S. Naveen
- Present Address: Indian Institute of Technology, BHU, Varanasi, India
| | - Guhan Jayaraman
- Bioprocess and Metabolic Engineering Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600036 India
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Hamann PR, Gomes TC, de M.B.Silva L, Noronha EF. Influence of lignin-derived phenolic compounds on the Clostridium thermocellum endo-β-1,4-xylanase XynA. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.02.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Acosta-Fernández R, Poerio T, Nabarlatz D, Giorno L, Mazzei R. Enzymatic Hydrolysis of Xylan from Coffee Parchment in Membrane Bioreactors. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.9b06429] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Rolando Acosta-Fernández
- INTERFASE, Chemical Engineering School, Universidad Industrial de Santander, Cra 27 No. 9, 680002Bucaramanga, Colombia
| | - Teresa Poerio
- Institute on Membrane Technology, National Research Council, ITM-CNR, Via P. Bucci 17/C at University of Calabria, 87036 Rende CS, Italy
| | - Debora Nabarlatz
- INTERFASE, Chemical Engineering School, Universidad Industrial de Santander, Cra 27 No. 9, 680002Bucaramanga, Colombia
| | - Lidietta Giorno
- Institute on Membrane Technology, National Research Council, ITM-CNR, Via P. Bucci 17/C at University of Calabria, 87036 Rende CS, Italy
| | - Rosalinda Mazzei
- Institute on Membrane Technology, National Research Council, ITM-CNR, Via P. Bucci 17/C at University of Calabria, 87036 Rende CS, Italy
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Maulana Hidayatullah I, Setiadi T, Tri Ari Penia Kresnowati M, Boopathy R. Xylanase inhibition by the derivatives of lignocellulosic material. BIORESOURCE TECHNOLOGY 2020; 300:122740. [PMID: 31952895 DOI: 10.1016/j.biortech.2020.122740] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/31/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Hydrolysis of lignocellulosic materials into simple sugar plays an important role in biorefinery. Hemicellulosic sugars from the hydrolysis of lignocellulosic materials could be used in xylitol production. However, xylanase activity during hydrolysis process is affected by activators and inhibitors that may present in the reaction system. The pretreatment process was reported to produce compounds that may affect the enzymatic hydrolysis process, such as furans, aliphatic acid, and aromatics. The purpose of this study was to investigate the inhibition effect of these potential inhibitors on xylanase activity. Three groups of potential inhibitors were evaluated including, furan, aliphatic acid, and hydrolysis-fermentation products. The result showed that ethanol, vanillin, and formic acid gave the highest inhibition effect from each group. Ethanol competed with xylanase competitively. Vanillin showed non-competitive inhibition. Formic acid performed mixed-inhibition by reducing maximum hydrolysis rate and giving varied Michaelis constant values at different concentrations.
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Affiliation(s)
- Ibnu Maulana Hidayatullah
- Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Bandung, Jalan Ganesha No. 10, Bandung 40132, Indonesia
| | - Tjandra Setiadi
- Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Bandung, Jalan Ganesha No. 10, Bandung 40132, Indonesia; Center for Environmental Studies (PSLH), Institut Teknologi Bandung, Jalan Sangkuriang 42 A, Bandung 40135, Indonesia
| | | | - Ramaraj Boopathy
- Department of Biological Sciences, Nicholls State University, Thibodaux, LA 70310, USA.
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Jung W, Sharma-Shivappa R, Park S, Kolar P. Effect of cellulolytic enzyme binding on lignin isolated from alkali and acid pretreated switchgrass on enzymatic hydrolysis. 3 Biotech 2020; 10:1. [PMID: 31815083 DOI: 10.1007/s13205-019-1978-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/29/2019] [Indexed: 10/25/2022] Open
Abstract
In this research, the binding of cellulolytic enzymes in Cellic® CTec2 on six lignin isolates obtained from alkali (0.5, 1.0, and 1.5% NaOH at 121 °C for 30 min) and acid (1, 2, and 3% H2SO4 at 121 °C for 60 min) pretreated switchgrass was investigated. Briefly, the hydrolysis of cellobiose and Avicel with and without (control) lignin isolates was performed via CTec2 (5 and 10 FPU g-1 carbohydrate) to determine whether the presence of lignin and binding of cellulolytic enzymes to the isolated lignin can affect the sugar production using three carbohydrate-lignin loadings, namely, 0.5:0.25, 0.5:0.5, and 0.5:1.0% (wv-1). Based on SDS-PAGE results, β-glucosidase (BG) was significantly bound to all lignin isolates. Some enzymes in CTec2 presumed to be cellobiohydrolases, endo-1,4-β-glucanases, and xylanase, were also observed to partially bind to the lignin isolates. Up to 0.97 g glucose g-1 cellobiose was produced via hydrolysis (72 h and pH 4.8) with CTec2 (5 and 10 FPU g-1 carbohydrate). Similarly, up to 0.23 and 0.46 g glucose g-1 Avicel were produced via hydrolysis (72 h and pH 4.8) with 5 and 10 FPU g-1 carbohydrate, respectively. Results indicated that the addition of lignin isolates during cellobiose and Avicel hydrolysis did not significantly (p > 0.05) reduce glucose production regardless of type and amount of lignin isolate. Hence, even though BG was significantly bound to lignin isolates, it could maintain its functionality as a biological catalyst in this study.
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Zerva A, Pentari C, Grisel S, Berrin JG, Topakas E. A new synergistic relationship between xylan-active LPMO and xylobiohydrolase to tackle recalcitrant xylan. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:142. [PMID: 32793303 PMCID: PMC7419196 DOI: 10.1186/s13068-020-01777-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/29/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND Hemicellulose accounts for a significant part of plant biomass, and still poses a barrier to the efficient saccharification of lignocellulose. The recalcitrant part of hemicellulose is a serious impediment to the action of cellulases, despite the use of xylanases in the cellulolytic cocktail mixtures. However, the complexity and variety of hemicelluloses in different plant materials require the use of highly specific enzymes for a complete breakdown. Over the last few years, new fungal enzymes with novel activities on hemicelluloses have emerged. In the present study, we explored the synergistic relationships of the xylan-active AA14 lytic polysaccharide monooxygenase (LPMO), PcAA14B, with the recently discovered glucuronoxylan-specific xylanase TtXyn30A, of the (sub)family GH30_7, displaying xylobiohydrolase activity, and with commercial cellobiohydrolases, on pretreated natural lignocellulosic substrates. RESULTS PcAA14B and TtXyn30A showed a strong synergistic interaction on the degradation of the recalcitrant part of xylan. PcAA14B was able to increase the release of xylobiose from TtXyn30A, showing a degree of synergism (DS) of 3.8 on birchwood cellulosic fibers, and up to 5.7 on pretreated beechwood substrates. The increase in activity was dose- and time- dependent. A screening study on beechwood materials pretreated with different methods showed that the effect of the PcAA14B-TtXyn30A synergism was more prominent on substrates with low hemicellulose content, indicating that PcAA14B is mainly active on the recalcitrant part of xylan, which is in close proximity to the underlying cellulose fibers. Simultaneous addition of both enzymes resulted in higher DS than sequential addition. Moreover, PcAA14B was found to enhance cellobiose release from cellobiohydrolases during hydrolysis of pretreated lignocellulosic substrates, as well as microcrystalline cellulose. CONCLUSIONS The results of the present study revealed a new synergistic relationship not only among two recently discovered xylan-active enzymes, the LPMO PcAA14B, and the GH30_7 glucuronoxylan-active xylobiohydrolase TtXyn30A, but also among PcAA14B and cellobiohydrolases. We hypothesize that PcAA14B creates free ends in the xylan polymer, which can be used as targets for the action of TtXyn30A. The results are of special importance for the design of next-generation enzymatic cocktails, able to efficiently remove hemicelluloses, allowing complete saccharification of cellulose in plant biomass.
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Affiliation(s)
- Anastasia Zerva
- Industrial Biotechnology and Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, 15780 Athens, Greece
- INRAE, Aix Marseille University, Biodiversité Et Biotechnologie Fongiques (BBF), UMR1163, 13009 Marseille, France
| | - Christina Pentari
- Industrial Biotechnology and Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, 15780 Athens, Greece
| | - Sacha Grisel
- INRAE, Aix Marseille University, Biodiversité Et Biotechnologie Fongiques (BBF), UMR1163, 13009 Marseille, France
| | - Jean-Guy Berrin
- INRAE, Aix Marseille University, Biodiversité Et Biotechnologie Fongiques (BBF), UMR1163, 13009 Marseille, France
| | - Evangelos Topakas
- Industrial Biotechnology and Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, 15780 Athens, Greece
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Tang S, Dong Q, Fang Z, Cong WJ, Miao ZD. High-concentrated substrate enzymatic hydrolysis of pretreated rice straw with glycerol and aluminum chloride at low cellulase loadings. BIORESOURCE TECHNOLOGY 2019; 294:122164. [PMID: 31563115 DOI: 10.1016/j.biortech.2019.122164] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/17/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
Rice straw was pretreated with glycerol and AlCl3 for enzymatic hydrolysis at low cellulase loadings. Based on a central composite design, 83% delignification, 94% hemicellulose removal, and 92% cellulose recovery (or 76% cellulose in solid residue) were achieved under the optimized pretreatment conditions (0.08 mol/L AlCl3 as catalyst at 146.8 °C for 20 min with 90% glycerol). During glycerol-AlCl3 pretreatment, the lignin-carbohydrate complex was depolymerized, resulting in the complex and recalcitrant construction of straw effectively being destroyed. The enzyme adsorption ability of pretreated straw was 16.5 times that for the original sample. After pretreatment, glucose yield was increased by 2.4 times to 74% for 48 h. Moreover, concentrated solid (15%) with low cellulase loading (3.3 FPU/g dry substrate) achieved 58.6% glucose yield, and further increased by 12% to 65.7% by adding Tween 80. Glycerol-AlCl3 pretreatment was a promising approach to realize high-concentrated solid hydrolysis for sugars at low cellulase loadings.
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Affiliation(s)
- Song Tang
- Biomass Group, College of Engineering, Nanjing Agricultural University, 40 Dianjiangtai Road, Nanjing, Jiangsu 210031, China
| | - Qian Dong
- Biomass Group, College of Engineering, Nanjing Agricultural University, 40 Dianjiangtai Road, Nanjing, Jiangsu 210031, China
| | - Zhen Fang
- Biomass Group, College of Engineering, Nanjing Agricultural University, 40 Dianjiangtai Road, Nanjing, Jiangsu 210031, China. http://biomass-group.njau.edu.cn/
| | - Wen-Jie Cong
- Biomass Group, College of Engineering, Nanjing Agricultural University, 40 Dianjiangtai Road, Nanjing, Jiangsu 210031, China
| | - Zheng-Diao Miao
- Biomass Group, College of Engineering, Nanjing Agricultural University, 40 Dianjiangtai Road, Nanjing, Jiangsu 210031, China
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Effect of Enzyme Interaction with Lignin Isolated from Pretreated Miscanthus x gigantues on Cellulolytic Efficiency. Processes (Basel) 2019. [DOI: 10.3390/pr7100755] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The effect of binding between the lignin isolates from an alkali (NaOH)– and an acid (H2SO4)– pretreated Miscanthus and cellulolytic enzymes in Cellic® CTec2 was investigated. Additonally, cellobiose and Avicel were enzymatically hydrolyzed with and without lignin isolates to study how enzyme binding onto lignin affects its conversion to glucose. Three carbohydrate–lignin loadings (0.5:0.25, 0.5:0.5, and 0.5:1.0% (w/v)) were employed. The results indicated that β-glucosidase (BG) had a strong tendency to bind to all lignin isolates. The overall tendency of enzyme binding onto lignin isolate was similar regardless of pretreatment chemical concentration. Though enzyme binding onto lignin isolates was observed, hydrolysis in the presence of these isolates did not have a significant (p > 0.05) impact on glucose production from cellobiose and Avicel. Cellobiose to glucose conversion of 99% was achieved via hydrolysis at both 5 and 10 FPU/g carbohydrate. Hydrolysis of Avicel with 5 and 10 FPU/g CTec2 resulted in 29.3 and 47.7% conversion to glucose, respectively.
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30
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Fuzzy-Enhanced Modeling of Lignocellulosic Biomass Enzymatic Saccharification. ENERGIES 2019. [DOI: 10.3390/en12112110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The enzymatic hydrolysis of lignocellulosic biomass incorporates many physico-chemical phenomena, in a heterogeneous and complex media. In order to make the modeling task feasible, many simplifications must be assumed. Hence, different simplified models, such as Michaelis-Menten and Langmuir-based ones, have been used to describe batch processes. However, these simple models have difficulties in predicting fed-batch operations with different feeding policies. To overcome this problem and avoid an increase in the complexity of the model by incorporating other phenomenological terms, a Takagi-Sugeno Fuzzy approach has been proposed, which manages a consortium of different simple models for this process. Pretreated sugar cane bagasse was used as biomass in this case study. The fuzzy rule combines two Michaelis-Menten-based models, each responsible for describing the reaction path for a distinct range of solids concentrations in the reactor. The fuzzy model improved fitting and increased prediction in a validation data set.
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31
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Kellock M, Maaheimo H, Marjamaa K, Rahikainen J, Zhang H, Holopainen-Mantila U, Ralph J, Tamminen T, Felby C, Kruus K. Effect of hydrothermal pretreatment severity on lignin inhibition in enzymatic hydrolysis. BIORESOURCE TECHNOLOGY 2019; 280:303-312. [PMID: 30776657 DOI: 10.1016/j.biortech.2019.02.051] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 05/19/2023]
Abstract
Hydrothermal pretreatment is commonly used for enhancing enzymatic hydrolysis of lignocellulosics. Spruce and wheat straw were pretreated with increasing severity and lignin characteristics were analysed. The effect of enzymatically isolated lignin on the hydrolysis of Avicel and the adsorption of a cellobiohydrolase onto lignin was measured. Non-pretreated lignins had only a minor effect on Avicel hydrolysis. The structural changes in lignin accompanying hydrothermal pretreatment were associated with increased binding and inactivation of the cellulase on the lignin surface. The inhibitory effect was more pronounced in spruce than in wheat straw lignin. However, similar pretreatment severities caused similar levels of inhibition in Avicel hydrolysis for both biomass sources. The combined severity factor of the pretreatment correlated well with the inhibitory effect of lignin.
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Affiliation(s)
- Miriam Kellock
- VTT Technical Research Centre of Finland Ltd, P.O Box 1000, 02044 VTT, Finland.
| | - Hannu Maaheimo
- VTT Technical Research Centre of Finland Ltd, P.O Box 1000, 02044 VTT, Finland.
| | - Kaisa Marjamaa
- VTT Technical Research Centre of Finland Ltd, P.O Box 1000, 02044 VTT, Finland.
| | - Jenni Rahikainen
- VTT Technical Research Centre of Finland Ltd, P.O Box 1000, 02044 VTT, Finland.
| | - Heng Zhang
- University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
| | | | - John Ralph
- University of Wisconsin, Madison, WI 53726, USA.
| | - Tarja Tamminen
- VTT Technical Research Centre of Finland Ltd, P.O Box 1000, 02044 VTT, Finland.
| | - Claus Felby
- University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
| | - Kristiina Kruus
- VTT Technical Research Centre of Finland Ltd, P.O Box 1000, 02044 VTT, Finland.
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32
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Wang Y, Gong X, Hu X, Zhou N. Lignin monomer in steam explosion assist chemical treated cotton stalk affects sugar release. BIORESOURCE TECHNOLOGY 2019; 276:343-348. [PMID: 30641333 DOI: 10.1016/j.biortech.2019.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 05/12/2023]
Abstract
In this study, the fermentable sugar released from cotton stalk (CS), which were pretreated by instant catapult steam explosion (SE) combined with different concentrations of strong monobasic acid (HCl), weak monobasic acid (CH3COOH), strong monobasic alkali (NaOH) and weak monobasic alkali (NH3·H2O), followed by hydrolysis in cellulase/xylanase mixed enzyme solutions, were comparably investigated. The highest yield of 73.22% of fermentable sugar yield was obtained in SE-2.4 MPa-5%NH3·H2O treated CS substrates, which was 5.14 times higher than that from enzymatic hydrolysis (EH) of raw CS. Furthermore, evaluation of monolignins content (H, G, S) in different CS samples suggested that substrates rich in guaiacyl (G) and syringyl (S) would generate a higher efficiency of enzymatic saccharification. Therefore, the slight genetic modification of monolignins for cotton stalk might be a potential way to enhance biomass degradation and transformation.
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Affiliation(s)
- Ya Wang
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, China
| | - Xiaowu Gong
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, China
| | - Xiaona Hu
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, China
| | - Na Zhou
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, China.
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33
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Wang Z, Zhang T, Long L, Ding S. Altering the linker in processive GH5 endoglucanase 1 modulates lignin binding and catalytic properties. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:332. [PMID: 30568732 PMCID: PMC6297974 DOI: 10.1186/s13068-018-1333-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND The non-productive adsorption of cellulases onto lignin in biomass is a key issue for the biofuel process economy. It would be helpful to reduce the inhibitory effect of lignin on enzymatic hydrolysis by engineering weak lignin-binding cellulases. Cellulase linkers are highly divergent in their lengths, compositions, and glycosylations. Numerous studies have revealed that linkers can facilitate optimal interactions between structured domains. Recently, efforts have focused on the contributions and mechanisms of carbohydrate-binding modules and catalytic domains that affect lignin affinity and processivity of cellulases, but our understanding of the effects of the linker regions on lignin adsorption and processivity of GH5 processive endoglucanases is still limited. RESULTS Eight GH5 endoglucanase 1 variants of varying length, flexibility, and sequence in the linker region were constructed. Their characteristics were then compared to the wild-type enzyme (EG1). Remarkably, significant differences in the lignin adsorption profiles and processivities were observed for EG1 and other variants. Our studies suggest that either the length or the specific amino acid composition of the linker has a prominent influence on the lignin-binding affinity of the enzymes. Comparatively, the processivity may depend primarily on the length of the linker and less so on the specific amino acid composition. EG1-ApCel5A, a variant with better performance in enzymatic hydrolysis in the presence of lignin, was obtained by replacing a longer, flexible linker. In total, up to between 28.2 and 30.1% more reducing sugars were generated from filter paper by EG1-ApCel5A in the presence of lignin compared to EG1. CONCLUSIONS Our results highlight the relevance of the linker region in the lignin adsorption and processivity of a processive endoglucanase. Our findings suggest that the linker region may be used as a target for the design of more active and weaker lignin-binding cellulases.
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Affiliation(s)
- Zhen Wang
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
| | - Tianrui Zhang
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
| | - Liangkun Long
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
| | - Shaojun Ding
- The Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab for the Chemistry & Utilization of Agricultural and Forest Biomass, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu China
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34
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Lu X, Feng X, Li X, Zhao J. The adsorption properties of endoglucanase to lignin and their impact on hydrolysis. BIORESOURCE TECHNOLOGY 2018; 267:110-116. [PMID: 30014989 DOI: 10.1016/j.biortech.2018.06.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 06/10/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
Nonproductive adsorption of cellulase to lignin dramatically influenced the hydrolysis efficiency of lignocellulose. By comparing the adsorption behaviors of CBH and EG, we found that the adsorption of EG to lignin showed lower adsorption velocity and capacity versus CBH. During the adsorption of EG to lignin, carbohydrate binding domain (CBM) and catalytic domain (CD) both played an important role by a two-step adsorption process, in which CD slowly bond on lignin and developed stronger interaction with lignin. The optimal binding position of EG on lignin was consistent with that on polysaccharide located in the open catalytic tunnel. So, the adsorption of EG to lignin not only limited the movement of enzyme, but also restricted the catalytic ability of enzyme, which dramatically influenced enzymatic hydrolysis. Increasing the proportion of EG in cellulase cocktails or engineering "weak lignin adsorbed" EG was necessary to relieve the influence of lignin adsorption on hydrolysis.
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Affiliation(s)
- Xianqin Lu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China
| | - Xiaoting Feng
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China.
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35
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Wang Z, Jönsson LJ. Comparison of catalytically non-productive adsorption of fungal proteins to lignins and pseudo-lignin using isobaric mass tagging. BIORESOURCE TECHNOLOGY 2018; 268:393-401. [PMID: 30099290 DOI: 10.1016/j.biortech.2018.07.149] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/28/2018] [Accepted: 07/30/2018] [Indexed: 06/08/2023]
Abstract
Catalytically non-productive adsorption of fungal enzymes to pseudo-lignin (PL) was compared to adsorption to lignin preparations derived from different sources (SL, spruce; BL, birch; OL, beech) using different methods [steam pretreatment/enzymatic saccharification (SL, BL) and organosolv processing (OL)]. The protein adsorption to the SL was more extensive than the adsorption to the hardwood lignins, which was relatively similar to the adsorption to the PL. The adsorption patterns of 13 individual proteins were studied using isobaric mass tagging with TMTsixplex reagent and LC-MS/MS analysis. The results suggest that, on an average, adsorption of proteins equipped with carbohydrate-binding modules, such as the cellulases CBHI, EGII, and EGIV, was less dependent on the quality of the lignin/PL than adsorption of other proteins, such as β-Xyl, Xyn-1, and Xyn-2, which are involved in xylan degradation.
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Affiliation(s)
- Zhao Wang
- Department of Chemistry, KBC Chemical-Biological Centre, Umeå University, SE-901 87 Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, KBC Chemical-Biological Centre, Umeå University, SE-901 87 Umeå, Sweden.
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36
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Djajadi DT, Pihlajaniemi V, Rahikainen J, Kruus K, Meyer AS. Cellulases adsorb reversibly on biomass lignin. Biotechnol Bioeng 2018; 115:2869-2880. [PMID: 30132790 PMCID: PMC6282830 DOI: 10.1002/bit.26820] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/30/2018] [Accepted: 08/13/2018] [Indexed: 12/14/2022]
Abstract
Adsorption of cellulases onto lignin is considered a major factor in retarding enzymatic cellulose degradation of lignocellulosic biomass. However, the adsorption mechanisms and kinetics are not well understood for individual types of cellulases. This study examines the binding affinity, kinetics of adsorption, and competition of four monocomponent cellulases of Trichoderma reesei during adsorption onto lignin.
TrCel7A,
TrCel6A,
TrCel7B, and
TrCel5A were radiolabeled for adsorption experiments on lignin‐rich residues (LRRs) isolated from hydrothermally pretreated spruce (L‐HPS) and wheat straw (L‐HPWS), respectively. On the basis of adsorption isotherms fitted to the Langmuir model, the ranking of binding affinities was
TrCel5A >
TrCel6A >
TrCel7B >
TrCel7A on both types of LRRs. The enzymes had a higher affinity to the L‐HPS than to the L‐HPWS. Adsorption experiments with dilution after 1 and 24 hr and kinetic modeling were performed to quantify any irreversible binding over time. Models with reversible binding parameters fitted well and can explain the results obtained. The adsorption constants obtained from the reversible models agreed with the fitted Langmuir isotherms and suggested that reversible adsorption–desorption existed at equilibrium. Competitive binding experiments showed that individual types of cellulases competed for binding sites on the lignin and the adsorption data fitted the Langmuir adsorption model. Overall, the data strongly indicate that the adsorption of cellulases onto lignin is reversible and the findings have implications for the development of more efficient cellulose degrading enzymes.
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Affiliation(s)
- Demi T Djajadi
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | | | | | - Anne S Meyer
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
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37
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Syaftika N, Matsumura Y. Comparative study of hydrothermal pretreatment for rice straw and its corresponding mixture of cellulose, xylan, and lignin. BIORESOURCE TECHNOLOGY 2018; 255:1-6. [PMID: 29414153 DOI: 10.1016/j.biortech.2018.01.085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/17/2018] [Accepted: 01/18/2018] [Indexed: 05/15/2023]
Abstract
We herein investigated the effect of hemicellulose and lignin on the hydrothermal pretreatment of lignocellulosic biomass for glucose production from cellulose in terms of structural cross-linking between cellulose and the above components. A comparison was made between the hydrothermal pretreatment of biomass and a mixture containing the individual model compounds in the same composition ratio. Thus, rice straw biomass and the mixture containing cellulose, xylan, and lignin were treated in an autoclave reactor at temperatures between 150 and 250 °C for 30 min. The obtained products were then subjected to enzymatic hydrolysis. Interestingly, different results were obtained for the two samples, as the presence of cross-linking between cellulose and lignin in the original biomass sample affected the efficiency of hydrothermal pretreatment. A model was therefore proposed to account for the obtained result in accordance with previous knowledge regarding the behavior of these compounds under hydrothermal conditions.
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Affiliation(s)
- Novi Syaftika
- Department of Mechanical Sciences and Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima, Hiroshima 739-8527, Japan
| | - Yukihiko Matsumura
- Department of Mechanical Sciences and Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima, Hiroshima 739-8527, Japan.
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38
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Wu J, Collins SRA, Elliston A, Wellner N, Dicks J, Roberts IN, Waldron KW. Release of cell wall phenolic esters during hydrothermal pretreatment of rice husk and rice straw. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:162. [PMID: 29991964 PMCID: PMC5994648 DOI: 10.1186/s13068-018-1157-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 05/30/2018] [Indexed: 05/04/2023]
Abstract
BACKGROUND Rice husk and rice straw represent promising sources of biomass for production of renewable fuels and chemicals. For efficient utilisation, lignocellulosic components must first be pretreated to enable efficient enzymatic saccharification and subsequent fermentation. Existing pretreatments create breakdown products such as sugar-derived furans, and lignin-derived phenolics that inhibit enzymes and fermenting organisms. Alkali pretreatments have also been shown to release significant levels of simple, free phenolics such as ferulic acid that are normally esterified to cell wall polysaccharides in the intact plant. These phenolics have recently been found to have considerable inhibitory properties. The aim of this research has been to establish the extent to which such free phenolic acids are also released during hydrothermal pretreatment of rice straw (RS) and rice husk (RH). RESULTS RS and RH were subjected to hydrothermal pretreatments over a wide range of severities (1.57-5.45). FTIR analysis showed that the pretreatments hydrolysed and solubilised hemicellulosic moieties, leading to an enrichment of lignin and crystalline cellulose in the insoluble residue. The residues also lost the capacity for UV autofluorescence at pH 7 or pH 10, indicating the breakdown or release of cell wall phenolics. Saponification of raw RS and RH enabled identification and quantification of substantial levels of simple phenolics including ferulic acid (tFA), coumaric acid (pCA) and several diferulic acids (DiFAs) including 8-O-4'-DiFA, 8,5'-DiFA and 5,5'-DiFA. RH had higher levels of pCA and lower levels of tFA and DiFAs compared with RS. Assessment of the pretreatment liquors revealed that pretreatment-liberated phenolics present were not free but remained as phenolic esters (at mM concentrations) that could be readily freed by saponification. Many were lost, presumably through degradation, at the higher severities. CONCLUSION Differences in lignin, tFA, DiFAs and pCA between RS and RH reflect differences in cell wall physiology, and probably contribute to the higher recalcitrance of RH compared with RS. Hydrothermal pretreatments, unlike alkali pretreatments, release cinnamic acid components as esters. The potential for pretreatment-liberated phenolic esters to be inhibitory to fermenting microorganisms is not known. However, the present study shows that they are found at concentrations that could be significantly inhibitory if released as free forms by enzyme activity.
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Affiliation(s)
- Jia Wu
- The Biorefinery Centre, Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Samuel R. A. Collins
- The Biorefinery Centre, Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Adam Elliston
- The Biorefinery Centre, Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Nikolaus Wellner
- Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Jo Dicks
- The National Collection of Yeast Cultures, Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Ian N. Roberts
- The National Collection of Yeast Cultures, Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Keith W. Waldron
- The Biorefinery Centre, Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA UK
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Djajadi DT, Jensen MM, Oliveira M, Jensen A, Thygesen LG, Pinelo M, Glasius M, Jørgensen H, Meyer AS. Lignin from hydrothermally pretreated grass biomass retards enzymatic cellulose degradation by acting as a physical barrier rather than by inducing nonproductive adsorption of enzymes. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:85. [PMID: 29619081 PMCID: PMC5880018 DOI: 10.1186/s13068-018-1085-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 03/17/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Lignin is known to hinder efficient enzymatic conversion of lignocellulose in biorefining processes. In particular, nonproductive adsorption of cellulases onto lignin is considered a key mechanism to explain how lignin retards enzymatic cellulose conversion in extended reactions. RESULTS Lignin-rich residues (LRRs) were prepared via extensive enzymatic cellulose degradation of corn stover (Zea mays subsp. mays L.), Miscanthus × giganteus stalks (MS) and wheat straw (Triticum aestivum L.) (WS) samples that each had been hydrothermally pretreated at three severity factors (log R0) of 3.65, 3.83 and 3.97. The LRRs had different residual carbohydrate levels-the highest in MS; the lowest in WS. The residual carbohydrate was not traceable at the surface of the LRRs particles by ATR-FTIR analysis. The chemical properties of the lignin in the LRRs varied across the three types of biomass, but monolignols composition was not affected by the severity factor. When pure cellulose was added to a mixture of LRRs and a commercial cellulolytic enzyme preparation, the rate and extent of glucose release were unaffected by the presence of LRRs regardless of biomass type and severity factor, despite adsorption of the enzymes to the LRRs. Since the surface of the LRRs particles were covered by lignin, the data suggest that the retardation of enzymatic cellulose degradation during extended reaction on lignocellulosic substrates is due to physical blockage of the access of enzymes to the cellulose caused by the gradual accumulation of lignin at the surface of the biomass particles rather than by nonproductive enzyme adsorption. CONCLUSIONS The study suggests that lignin from hydrothermally pretreated grass biomass retards enzymatic cellulose degradation by acting as a physical barrier blocking the access of enzymes to cellulose rather than by inducing retardation through nonproductive adsorption of enzymes.
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Affiliation(s)
- Demi T. Djajadi
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Mads M. Jensen
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Marlene Oliveira
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Anders Jensen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Lisbeth G. Thygesen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Manuel Pinelo
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Marianne Glasius
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Henning Jørgensen
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
- Present Address: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Anne S. Meyer
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
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Han X, Liu G, Song W, Qu Y. Production of sodium gluconate from delignified corn cob residue by on-site produced cellulase and co-immobilized glucose oxidase and catalase. BIORESOURCE TECHNOLOGY 2018; 248:248-257. [PMID: 28716292 DOI: 10.1016/j.biortech.2017.06.109] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/13/2017] [Accepted: 06/14/2017] [Indexed: 06/07/2023]
Abstract
The production of sodium gluconate by enzymatic catalysis of delignified corn cob residue (DCCR) hydrolysate was studied. Penicillium oxalicum I1-13 was used for the production of cellulase with high β-glucosidase activity. A fed-batch saccharification process was developed to obtain high yields of glucose. At the end of hydrolysis, the concentration of glucose reached 145.80g/L. Glucose oxidase and catalase were co-immobilized to catalyze DCCR hydrolysate to produce sodium gluconate. Under the optimum conditions, 166.87g/L sodium gluconate was obtained after 56h of reaction, with a yield of 98.24%. The immobilized enzymes could still maintain more than 60% of the activity after repeated use for 6 times. This study provides a potential route for the production of valuable chemicals by enzymatic conversion of lignocellulosic materials.
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Affiliation(s)
- Xiaolong Han
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China
| | - Wenxia Song
- School of Life Science, Qufu Normal University, Qufu 273165, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
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41
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Lu X, Wang C, Li X, Zhao J. Temperature and pH influence adsorption of cellobiohydrolase onto lignin by changing the protein properties. BIORESOURCE TECHNOLOGY 2017; 245:819-825. [PMID: 28926914 DOI: 10.1016/j.biortech.2017.08.139] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/21/2017] [Accepted: 08/22/2017] [Indexed: 05/03/2023]
Abstract
Non-productive adsorption of cellulase onto lignin restricted the movement of cellulase and also hindered the cellulase recycling in bioconversion of lignocellulose. In this study, effect of temperature and pH on adsorption and desorption of cellobiohydrolase (CBH) on lignin and its possible mechanism were discussed. It found that pH value and temperature influenced the adsorption and desorption behaviors of CBH on lignin. Different thermodynamic models suggested that the action between lignin and CBH was physical action. More CBH was adsorbed onto lignin, but lower initial adsorption velocity was detected at 50°C comparing with 4°C. Elevating pH value could improve desorption of cellulase from lignin. The changes of hydrophobicity and electric potential on protein surface may partially explain the impact of environmental conditions on the adsorption and desorption behaviors of CBH on lignin, and comparing to electrical interaction, the hydrophobicity may be the dominating factor influencing the behaviors.
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Affiliation(s)
- Xianqin Lu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China
| | - Can Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China.
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Yao L, Yang H, Yoo CG, Meng X, Li M, Pu Y, Ragauskas AJ, Sykes RW. Adsorption of cellobiohydrolases I onto lignin fractions from dilute acid pretreated Broussonetia papyrifera. BIORESOURCE TECHNOLOGY 2017; 244:957-962. [PMID: 28847086 DOI: 10.1016/j.biortech.2017.08.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/04/2017] [Accepted: 08/05/2017] [Indexed: 06/07/2023]
Abstract
Broussonetia papyrifera, known as paper mulberry, is a potential feed stock for bioethanol production because of its cellulose-rich composition. Lignin in dilute acid pretreated Broussonetia papyrifera was fractionated to three different fractions, and their physiochemical properties were determined by FT-IR, GPC and NMR analyses. Different structural characteristics were observed from each lignin fraction. Cellobiohydrolases I (CBH) adsorption to each lignin was understood by the lignin properties. The results showed that aliphatic hydroxyl groups in lignin showed positive correlations with the maximum binding ability of CBH onto lignin samples. Also, the contents of phenolic compounds such as p-hydroxyphenyl benzoate (PB), syringyl (S) and guaiacyl (G) units in the lignin influenced their CBH binding.
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Affiliation(s)
- Lan Yao
- School of Pulp & Paper Engineering, Hubei University of Technology, Wuhan 430068, China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China; Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996-2200, USA
| | - Haitao Yang
- School of Pulp & Paper Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Chang Geun Yoo
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996-2200, USA
| | - Mi Li
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yunqiao Pu
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Arthur J Ragauskas
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996-2200, USA; Department of Forestry, Wildlife and Fisheries, Center of Renewable Carbon, The University of Tennessee, Institute of Agriculture, Knoxville, TN 37996-2200, USA.
| | - Robert W Sykes
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
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