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Li ZC, Li W, Wang R, Wang DX, Tang AN, Wang XP, Gao XP, Zhao GM, Kong DM. Lignin-based covalent organic polymers with improved crystallinity for non-targeted analysis of chemical hazards in food samples. JOURNAL OF HAZARDOUS MATERIALS 2023; 448:130821. [PMID: 36709736 DOI: 10.1016/j.jhazmat.2023.130821] [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: 10/20/2022] [Revised: 01/16/2023] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Lignin, the most abundant source of renewable aromatic compounds derived from natural lignocellulosic biomass, has great potential for various applications as green materials due to its abundant active groups. However, it is still challenging to quickly construct green polymers with a certain crystallinity by utilizing lignin as a building block. Herein, new green lignin-based covalent organic polymers (LIGOPD-COPs) were one-pot fabricated with water as the reaction solvent and natural lignin as the raw material. Furthermore, by using paraformaldehyde as a protector and modulator, the LIGOPD-COPs prepared under optimized conditions displayed better crystallinity than reported lignin-based polymers, demonstrating the feasibility of preparing lignin-based polymers with improved crystallinity. The improved crystallinity confers LIGOPD-COPs with enhanced application performance, which was demonstrated by their excellent performances in sample treatment of non-targeted food safety analysis. Under optimized conditions, phytochromes, the main interfering matrices, were almost completely removed from different phytochromes-rich vegetables by LIGOPD-COPs, accompanied by "full recovery" of 90 chemical hazards. Green, low-cost, and reusable properties, together with improved crystallinity, will accelerate the industrialization and marketization of lignin-based COPs, and promote their applications in many fields.
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Affiliation(s)
- Zhan-Chao Li
- Henan Key Laboratory of Meat Processing and Quality Safety Control, College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, People's Republic of China; State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, People's Republic of China
| | - Wei Li
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, People's Republic of China.
| | - Rui Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, People's Republic of China
| | - Dong-Xia Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, People's Republic of China
| | - An-Na Tang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, People's Republic of China
| | - Xiao-Peng Wang
- Henan Key Laboratory of Meat Processing and Quality Safety Control, College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, People's Republic of China
| | - Xiao-Ping Gao
- Henan Key Laboratory of Meat Processing and Quality Safety Control, College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, People's Republic of China
| | - Gai-Ming Zhao
- Henan Key Laboratory of Meat Processing and Quality Safety Control, College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, People's Republic of China
| | - De-Ming Kong
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, People's Republic of China.
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Zhang B, Liu X, Bao J. High solids loading pretreatment: The core of lignocellulose biorefinery as an industrial technology - An overview. BIORESOURCE TECHNOLOGY 2023; 369:128334. [PMID: 36403909 DOI: 10.1016/j.biortech.2022.128334] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/08/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
Pretreatment is the first and most determinative, yet the least mature step of lignocellulose biorefinery chain. The current stagnation of biorefinery commercialization indicates the barriers of the existing pretreatment technologies are needed to be unlocked. This review focused on one of the core factors, the high lignocellulose solids loading in pretreatment. The high solids loading of pretreatment significantly reduces water input, energy requirement, toxic compound discharge, solid/liquid separation costs, and carbon dioxide emissions, improves the titers of sugars and biproducts to meet the industrial requirements. Meanwhile, lignocellulose feedstock after high solids loading pretreatment is compatible with the existing logistics system for densification, packaging, storage, and transportation. Both the technical-economic analysis and the cellulosic ethanol conversion performance suggest that the solids loading in the pretreatment step need to be further elevated towards an industrial technology and the effective solutions should be proposed to the technical barriers in high solids loading pretreatment operations.
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Affiliation(s)
- Bin Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Xiucai Liu
- Cathay Biotech Inc, 1690 Cailun Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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de Mélo AHF, Nunes AL, Carvalho PH, da Silva MF, Teixeira GS, Goldbeck R. Evaluation of Saccharomyces cerevisiae modified via CRISPR/Cas9 as a cellulosic platform microorganism in simultaneously saccharification and fermentation processes. Bioprocess Biosyst Eng 2022:10.1007/s00449-022-02765-1. [PMID: 35932337 DOI: 10.1007/s00449-022-02765-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/26/2022] [Indexed: 11/26/2022]
Abstract
The nonrenewable character and deleterious effects of fossil fuels foster the need for cleaner and more inexhaustible energy sources, such as bioethanol. Especially from lignocellulosic biomasses. However, the economic viability of this product in the market depends on process optimization and cost reduction. This research applied a sequential experimental project to investigate the process of enzymatic saccharification and simultaneous fermentation to produce ethanol with sugarcane bagasse. The differential of the work was the application of the strain of Saccharomyces cerevisiae AGY001 which was improved by evolutionary engineering to become thermotolerant and by a heterologous expression based on genomic integration by CRISPR/Cas9 to produce endoglucanase and β-glucosidase (AsENDO-AsBGL). The maximum ethanol yield found was 89% of the maximum theoretical yield (released sugars), obtained at temperature concentrations, sugarcane bagasse and inoculum at 40 °C, 16.5%, and 4.0 g/L, respectively (12.5 FPU/g bagasse). The mathematical model obtained can predict approximately 83% of the data set with 95% confidence. Therefore, these findings demonstrated the potential of sugarcane bagasse and S. cerevisiae AGY001 strain (CRISPR/Cas9 modified) in bioethanol production without the need for impractical selection media on an industrial scale, in addition to providing useful insights for the development of SSF processes.
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Affiliation(s)
- Allan H F de Mélo
- Bioprocess and Metabolic Engineering Laboratory, Food Engineering and Technology Department, School of Food Engineering, University of Campinas, Campinas, Campinas, SP, Brazil
| | - Alexia L Nunes
- Bioprocess and Metabolic Engineering Laboratory, Food Engineering and Technology Department, School of Food Engineering, University of Campinas, Campinas, Campinas, SP, Brazil
| | - Priscila H Carvalho
- Bioprocess and Metabolic Engineering Laboratory, Food Engineering and Technology Department, School of Food Engineering, University of Campinas, Campinas, Campinas, SP, Brazil
| | - Marcos F da Silva
- Bioprocess and Metabolic Engineering Laboratory, Food Engineering and Technology Department, School of Food Engineering, University of Campinas, Campinas, Campinas, SP, Brazil
| | - Gleidson S Teixeira
- Bioprocess and Metabolic Engineering Laboratory, Food Engineering and Technology Department, School of Food Engineering, University of Campinas, Campinas, Campinas, SP, Brazil
| | - Rosana Goldbeck
- Bioprocess and Metabolic Engineering Laboratory, Food Engineering and Technology Department, School of Food Engineering, University of Campinas, Campinas, Campinas, SP, Brazil.
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Wang Y, Chan KL, Abdel-Rahman MA, Sonomoto K, Leu SY. Dynamic simulation of continuous mixed sugar fermentation with increasing cell retention time for lactic acid production using Enterococcus mundtii QU 25. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:112. [PMID: 32607127 PMCID: PMC7318410 DOI: 10.1186/s13068-020-01752-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND The simultaneous and effective conversion of both pentose and hexose in fermentation is a critical and challenging task toward the lignocellulosic economy. This study aims to investigate the feasibility of an innovative co-fermentation process featuring with a cell recycling unit (CF/CR) for mixed sugar utilization. A l-lactic acid-producing strain Enterococcus mundtii QU 25 was applied in the continuous fermentation process, and the mixed sugars were utilized at different productivities after the flowing conditions were changed. A mathematical model was constructed with the experiments to optimize the biological process and clarify the cell metabolism through kinetics analysis. The structured model, kinetic parameters, and achievement of the fermentation strategy shall provide new insights toward whole sugar fermentation via real-time monitoring for process control and optimization. RESULTS Significant carbon catabolite repression in co-fermentation using a glucose/xylose mixture was overcome by replacing glucose with cellobiose, and the ratio of consumed pentose to consumed hexose increased significantly from 0.096 to 0.461 by mass. An outstanding product concentration of 65.2 g L-1 and productivity of 13.03 g L-1 h-1 were achieved with 50 g L-1 cellobiose and 30 g L-1 xylose at an optimized dilution rate of 0.2 h-1, and the cell retention time gradually increased. Among the total lactic acid production, xylose contributed to more than 34% of the mixed sugars, which was close to the related contents in agricultural residuals. The model successfully simulated the transition of sugar consumption, cell growth, and lactic acid production among the batch, continuous process, and CF/CR systems. CONCLUSION Cell retention time played a critical role in balancing pentose and hexose consumption, cell decay, and lactic acid production in the CF/CR process. With increasing cell concentration, consumption of mixed sugars increased with the productivity of the final product; hence, the impact of substrate inhibition was reduced. With the validated parameters, the model showed the highest accuracy simulating the CF/CR process, and significantly longer cell retention times compared to hydraulic retention time were tested.
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Affiliation(s)
- Ying Wang
- Department of Biological Science, College of Life Sciences, Sichuan Normal University, Chengdu, 610101 Sichuan China
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Ka-Lai Chan
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Mohamed Ali Abdel-Rahman
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Motooka, Nishi‐ku, Fukuoka, Japan
- Botany and Microbiology Department, Faculty of Science (Boys), Al-Azhar University, PN:11884, Nasr City, Cairo, Egypt
| | - Kenji Sonomoto
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Motooka, Nishi‐ku, Fukuoka, Japan
| | - Shao-Yuan Leu
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Kowloon, Hong Kong
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Serrà A, Artal R, García‐Amorós J, Sepúlveda B, Gómez E, Nogués J, Philippe L. Hybrid Ni@ZnO@ZnS-Microalgae for Circular Economy: A Smart Route to the Efficient Integration of Solar Photocatalytic Water Decontamination and Bioethanol Production. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1902447. [PMID: 32042564 PMCID: PMC7001628 DOI: 10.1002/advs.201902447] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/11/2019] [Indexed: 05/18/2023]
Abstract
Water remediation and development of carbon-neutral fuels are a priority for the evermore industrialized society. The answer to these challenges should be simple, sustainable, and inexpensive. Thus, biomimetic-inspired circular and holistic processes combing water remediation and biofuel production can be an appealing concept to deal with these global issues. A simple circular approach using helical Spirulina platensis microalgae as biotemplates to synthesize Ni@ZnO@ZnS photocatalysts for efficient solar water decontamination and bioethanol production during the recycling process is presented. Under solar irradiation, the Ni@ZnO@ZnS-Spirulina photocatalyst exhibits enhanced activity (mineralization efficiency >99%) with minimal photocorrosion and excellent reusability. At the end of its effective lifetime for water remediation, the microalgae skeleton (mainly glycogen and glucose) of the photocatalyst is recycled to directly produce bioethanol by simultaneous saccharification and fermentation process. An outstanding ethanol yield of 0.4 L kg-1, which is similar to the highest yield obtained from oxygenic photosynthetic microorganisms, is obtained. Thus, the entire process allows effective solar photocatalytic water remediation and bioethanol production at room temperature using simple and easily scalable procedures that simultaneously fixes carbon dioxide, thereby constituting a zero-carbon-emission circular process.
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Affiliation(s)
- Albert Serrà
- EmpaSwiss Federal Laboratories for Materials Science and TechnologyLaboratory for Mechanics of Materials and NanostructuresFeuerwerkerstrasse 39CH‐3602ThunSwitzerland
| | - Raül Artal
- Grup d'Electrodeposició de Capes Primes i Nanoestructures (GE‐CPN)Departament de Ciència de Materials i Química FísicaUniversitat de BarcelonaMartí i Franquès, 1E‐08028BarcelonaCataloniaSpain
| | - Jaume García‐Amorós
- Institute of Nanoscience and Nanotechnology (IN2UB)Universitat de BarcelonaE‐08028BarcelonaCataloniaSpain
- Grup de Materials OrgànicsDepartament de Química Inorgànica i OrgànicaUniversitat de BarcelonaMartí i Franquès, 1E‐08028BarcelonaCataloniaSpain
| | - Borja Sepúlveda
- Catalan Institute of Nanoscience and Nanotechnology (ICN2)CSIC and BISTCampus UABBellaterraE‐08193BarcelonaSpain
| | - Elvira Gómez
- Grup d'Electrodeposició de Capes Primes i Nanoestructures (GE‐CPN)Departament de Ciència de Materials i Química FísicaUniversitat de BarcelonaMartí i Franquès, 1E‐08028BarcelonaCataloniaSpain
- Institute of Nanoscience and Nanotechnology (IN2UB)Universitat de BarcelonaE‐08028BarcelonaCataloniaSpain
| | - Josep Nogués
- Catalan Institute of Nanoscience and Nanotechnology (ICN2)CSIC and BISTCampus UABBellaterraE‐08193BarcelonaSpain
- ICREAPg. Lluís Companys 23E‐08010BarcelonaSpain
| | - Laetitia Philippe
- EmpaSwiss Federal Laboratories for Materials Science and TechnologyLaboratory for Mechanics of Materials and NanostructuresFeuerwerkerstrasse 39CH‐3602ThunSwitzerland
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Wang Y, Leng L, Islam MK, Liu F, Lin CSK, Leu SY. Substrate-Related Factors Affecting Cellulosome-Induced Hydrolysis for Lignocellulose Valorization. Int J Mol Sci 2019; 20:ijms20133354. [PMID: 31288425 PMCID: PMC6651384 DOI: 10.3390/ijms20133354] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/30/2019] [Accepted: 07/03/2019] [Indexed: 11/22/2022] Open
Abstract
Cellulosomes are an extracellular supramolecular multienzyme complex that can efficiently degrade cellulose and hemicelluloses in plant cell walls. The structural and unique subunit arrangement of cellulosomes can promote its adhesion to the insoluble substrates, thus providing individual microbial cells with a direct competence in the utilization of cellulosic biomass. Significant progress has been achieved in revealing the structures and functions of cellulosomes, but a knowledge gap still exists in understanding the interaction between cellulosome and lignocellulosic substrate for those derived from biorefinery pretreatment of agricultural crops. The cellulosomic saccharification of lignocellulose is affected by various substrate-related physical and chemical factors, including native (untreated) wood lignin content, the extent of lignin and xylan removal by pretreatment, lignin structure, substrate size, and of course substrate pore surface area or substrate accessibility to cellulose. Herein, we summarize the cellulosome structure, substrate-related factors, and regulatory mechanisms in the host cells. We discuss the latest advances in specific strategies of cellulosome-induced hydrolysis, which can function in the reaction kinetics and the overall progress of biorefineries based on lignocellulosic feedstocks.
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Affiliation(s)
- Ying Wang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ling Leng
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
| | - Md Khairul Islam
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Fanghua Liu
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
| | - Carol Sze Ki Lin
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Shao-Yuan Leu
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
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Kim DH, Park HM, Jung YH, Sukyai P, Kim KH. Pretreatment and enzymatic saccharification of oak at high solids loadings to obtain high titers and high yields of sugars. BIORESOURCE TECHNOLOGY 2019; 284:391-397. [PMID: 30959376 DOI: 10.1016/j.biortech.2019.03.134] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 05/28/2023]
Abstract
Production of high-titer sugar from lignocellulose is important in terms of process economics of bio-based product industry. In this study, to obtain high titers and yields of sugars, we combined pretreatment and saccharification steps, both at high solids loadings. First, pretreatment of oak was optimized at a 30% (w/w) solids loading. The whole slurry of the pretreated oak was subjected to a fed-batch saccharification step at the final solids loading of 30%, to minimize loss of fermentable sugars and simplify the processes. As a result, high-titer sugars (157.5 g/L) consisting of 120.2 g/L of glucose and 37.3 g/L of xylose were obtained at 75.9% and 58.6%, respectively, of theoretical maximum yields, based on the initial glucan and xylan contents. Thus, through proper optimization processes of oak, the combination of pretreatment and saccharification at high solids loadings was effective in obtaining both high titers and high yields of sugars from lignocellulose.
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Affiliation(s)
- Dong Hyun Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, South Korea
| | - Hyun Min Park
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, South Korea
| | - Young Hoon Jung
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, South Korea
| | - Prakit Sukyai
- Biotechnology of Biopolymers and Bioactive Compounds Special Research Unit, Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, South Korea.
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Acid Assisted Organosolv Delignification of Beechwood and Pulp Conversion towards High Concentrated Cellulosic Ethanol via High Gravity Enzymatic Hydrolysis and Fermentation. Molecules 2018; 23:molecules23071647. [PMID: 29976912 PMCID: PMC6099605 DOI: 10.3390/molecules23071647] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 12/26/2022] Open
Abstract
Background: Future biorefineries will focus on converting low value waste streams to chemical products that are derived from petroleum or refined sugars. Feedstock pretreatment in a simple, cost effective, agnostic manner is a major challenge. Methods: In this work, beechwood sawdust was delignified via an organosolv process, assisted by homogeneous inorganic acid catalysis. Mixtures of water and several organic solvents were evaluated for their performance. Specifically, ethanol (EtOH), acetone (AC), and methyl- isobutyl- ketone (MIBK) were tested with or without the use of homogeneous acid catalysis employing sulfuric, phosphoric, and oxalic acids under relatively mild temperature of 175 °C for one hour. Results: Delignification degrees (DD) higher than 90% were achieved, where both AC and EtOH proved to be suitable solvents for this process. Both oxalic and especially phosphoric acid proved to be good alternative catalysts for replacing sulfuric acid. High gravity simultaneous saccharification and fermentation with an enzyme loading of 8.4 mg/gsolids at 20 wt.% initial solids content reached an ethanol yield of 8.0 w/v%. Conclusions: Efficient delignification combining common volatile solvents and mild acid catalysis allowed for the production of ethanol at high concentration in an efficient manner.
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Matsakas L, Nitsos C, Raghavendran V, Yakimenko O, Persson G, Olsson E, Rova U, Olsson L, Christakopoulos P. A novel hybrid organosolv: steam explosion method for the efficient fractionation and pretreatment of birch biomass. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:160. [PMID: 29930706 PMCID: PMC5992717 DOI: 10.1186/s13068-018-1163-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/01/2018] [Indexed: 05/02/2023]
Abstract
BACKGROUND The main role of pretreatment is to reduce the natural biomass recalcitrance and thus enhance saccharification yield. A further prerequisite for efficient utilization of all biomass components is their efficient fractionation into well-defined process streams. Currently available pretreatment methods only partially fulfill these criteria. Steam explosion, for example, excels as a pretreatment method but has limited potential for fractionation, whereas organosolv is excellent for delignification but offers poor biomass deconstruction. RESULTS In this article, a hybrid method combining the cooking and fractionation of conventional organosolv pretreatment with the implementation of an explosive discharge of the cooking mixture at the end of pretreatment was developed. The effects of various pretreatment parameters (ethanol content, duration, and addition of sulfuric acid) were evaluated. Pretreatment of birch at 200 °C with 60% v/v ethanol and 1% w/wbiomass H2SO4 was proven to be the most efficient pretreatment condition yielding pretreated solids with 77.9% w/w cellulose, 8.9% w/w hemicellulose, and 7.0 w/w lignin content. Under these conditions, high delignification of 86.2% was demonstrated. The recovered lignin was of high purity, with cellulose and hemicellulose contents not exceeding 0.31 and 3.25% w/w, respectively, and ash to be < 0.17% w/w in all cases, making it suitable for various applications. The pretreated solids presented high saccharification yields, reaching 68% at low enzyme load (6 FPU/g) and complete saccharification at high enzyme load (22.5 FPU/g). Finally, simultaneous saccharification and fermentation (SSF) at 20% w/w solids yielded an ethanol titer of 80 g/L after 192 h, corresponding to 90% of the theoretical maximum. CONCLUSIONS The novel hybrid method developed in this study allowed for the efficient fractionation of birch biomass and production of pretreated solids with high cellulose and low lignin contents. Moreover, the explosive discharge at the end of pretreatment had a positive effect on enzymatic saccharification, resulting in high hydrolyzability of the pretreated solids and elevated ethanol titers in the following high-gravity SSF. To the best of our knowledge, the ethanol concentration obtained with this method is the highest so far for birch biomass.
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Affiliation(s)
- Leonidas Matsakas
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
| | - Christos Nitsos
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
| | - Vijayendran Raghavendran
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden
- Present Address: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN UK
| | - Olga Yakimenko
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
| | - Gustav Persson
- Department of Physics, Chalmers University of Technology, Fysikgränd 3, 412 96 Göteborg, Sweden
| | - Eva Olsson
- Department of Physics, Chalmers University of Technology, Fysikgränd 3, 412 96 Göteborg, Sweden
| | - Ulrika Rova
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
| | - Lisbeth Olsson
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
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