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Averheim A, Stagge S, Jönsson LJ, Larsson SH, Thyrel M. Separate hydrolysis and fermentation of softwood bark pretreated with 2-naphthol by steam explosion. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:102. [PMID: 39020440 PMCID: PMC11253379 DOI: 10.1186/s13068-024-02552-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Accepted: 07/08/2024] [Indexed: 07/19/2024]
Abstract
BACKGROUND 2-Naphthol, a carbocation scavenger, is known to mitigate lignin condensation during the acidic processing of lignocellulosic biomass, which may benefit downstream processing of the resulting materials. Consequently, various raw materials have demonstrated improved enzymatic saccharification yields for substrates pretreated through autohydrolysis and dilute acid hydrolysis in the presence of 2-naphthol. However, 2-naphthol is toxic to ethanol-producing organisms, which may hinder its potential application. Little is known about the implications of 2-naphthol in combination with the pretreatment of softwood bark during continuous steam explosion in an industrially scalable system. RESULTS The 2-naphthol-pretreated softwood bark was examined through spectroscopic techniques and subjected to separate hydrolysis and fermentation along with a reference excluding the scavenger and a detoxified sample washed with ethanol. The extractions of the pretreated materials with water resulted in a lower aromatic content in the extracts and stronger FTIR signals, possibly related to guaiacyl lignin, in the nonextractable residue when 2-naphthol was used during pretreatment. In addition, cyclohexane/acetone (9:1) extraction revealed the presence of pristine 2-naphthol in the extracts and increased aromatic content of the nonextractable residue detectable by NMR for the scavenger-pretreated materials. Whole-slurry enzymatic saccharification at 12% solids loading revealed that elevated saccharification recoveries after 48 h could not be achieved with the help of the scavenger. Glucose concentrations of 16.9 (reference) and 15.8 g/l (2-naphthol) could be obtained after 48 h of hydrolysis. However, increased inhibition during fermentation of the scavenger-pretreated hydrolysate, indicated by yeast cell growth, was slight and could be entirely overcome by the detoxification stage. The ethanol yields from fermentable sugars after 24 h were 0.45 (reference), 0.45 (2-naphthol), and 0.49 g/g (2-naphthol, detoxified). CONCLUSION The carbocation scavenger 2-naphthol did not increase the saccharification yield of softwood bark pretreated in an industrially scalable system for continuous steam explosion. On the other hand, it was shown that the scavenger's inhibitory effects on fermenting microorganisms can be overcome by controlling the pretreatment conditions to avoid cross-inhibition or detoxifying the substrates through ethanol washing. This study underlines the need to jointly optimize all the main processing steps.
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Affiliation(s)
- Andreas Averheim
- Fiber Technology Center, Valmet AB, 851 94, Sundsvall, Sweden.
- Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden.
| | - Stefan Stagge
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| | - Sylvia H Larsson
- Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Mikael Thyrel
- Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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Tan R, Sun Q, Yan Y, Chen T, Wang Y, Li J, Guo X, Fan Z, Zhang Y, Chen L, Wu G, Wu N. Co-production of pigment and high value-added bacterial nanocellulose from Suaeda salsa biomass with improved efficiency of enzymatic saccharification and fermentation. Front Bioeng Biotechnol 2023; 11:1307674. [PMID: 38098970 PMCID: PMC10720727 DOI: 10.3389/fbioe.2023.1307674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 11/21/2023] [Indexed: 12/17/2023] Open
Abstract
This study evaluated the co-production of pigment and bacterial nanocellulose (BNC) from S. salsa biomass. The extraction of the beet red pigment reduced the salts and flavonoids contents by 82.7%-100%, promoting the efficiencies of enzymatic saccharification of the biomass and the fermentation of BNC from the hydrolysate. SEM analysis revealed that the extraction process disrupted the lignocellulosic fiber structure, and the chemical analysis revealed the lessened cellulase inhibitors, consequently facilitating enzymatic saccharification for 10.4 times. BNC producing strains were found to be hyper-sensitive to NaCl stress, produced up to 400.4% more BNC from the hydrolysate after the extraction. The fermentation results of BNC indicated that the LDU-A strain yielded 2.116 g/L and 0.539 g/L in ES-M and NES-M, respectively. In comparison to the control, the yield in ES-M increased by approximately 20.0%, while the enhancement in NES-M was more significant, reaching 292.6%. After conducting a comprehensive characterization of BNC derived from S. salsa through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Thermogravimetric Analysis (TGA), the average fiber diameter distribution of these four BNC materials ranges from 22.23 to 33.03 nanometers, with a crystallinity range of 77%-90%. Additionally, they exhibit a consistent trend during the thermal degradation process, further emphasizing their stability in high-temperature environments and similar thermal properties. Our study found an efficient co-production approach of pigment and BNC from S. salsa biomass. Pigment extraction made biomass more physically and chemically digestible to cellulase, and significantly improved BNC productivity and quality.
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Affiliation(s)
- Ran Tan
- Shandong Key Laboratory of Edible Mushroom Technology, School of Agriculture, Ludong University, Yantai, China
| | - Qiwei Sun
- Shandong Key Laboratory of Edible Mushroom Technology, School of Agriculture, Ludong University, Yantai, China
| | - Yiran Yan
- Shandong Key Laboratory of Edible Mushroom Technology, School of Agriculture, Ludong University, Yantai, China
| | - Tao Chen
- Shandong Key Laboratory of Edible Mushroom Technology, School of Agriculture, Ludong University, Yantai, China
| | - Yifei Wang
- Shandong Key Laboratory of Edible Mushroom Technology, School of Agriculture, Ludong University, Yantai, China
| | - Jiakun Li
- Shandong Key Laboratory of Edible Mushroom Technology, School of Agriculture, Ludong University, Yantai, China
| | - Xiaohong Guo
- School of Resources and Environmental Engineering, Ludong University, Yantai, China
| | - Zuoqing Fan
- Shandong Institute of Sericulture, Yantai, China
| | - Yao Zhang
- School of Chemistry and Materials Science, Ludong University, Yantai, China
| | - Linxu Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Guochao Wu
- Shandong Key Laboratory of Edible Mushroom Technology, School of Agriculture, Ludong University, Yantai, China
- Key Laboratory of Molecular Module-Based Breeding of High Yield and Abiotic Resistant Plants in Universities of Shandong, School of Agriculture, Ludong University, Yantai, China
| | - Nan Wu
- School of Resources and Environmental Engineering, Ludong University, Yantai, China
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David AJ, Abinandan S, Vaidyanathan VK, Xu CC, Krishnamurthi T. `A critical review on current status and environmental sustainability of pre-treatment methods for bioethanol production from lignocellulose feedstocks. 3 Biotech 2023; 13:233. [PMID: 37323858 PMCID: PMC10260725 DOI: 10.1007/s13205-023-03657-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 06/04/2023] [Indexed: 06/17/2023] Open
Abstract
Lignocellulosic biomass resource has been widely used as a natural resource for the synthesis of biofuels and bio-based products through pre-treatment, saccharification and fermentation processes. In this review, we delve into the environmental implications of bioethanol production from the widely utilized lignocellulosic biomass resource. The focus of our study is the critical stage of pre-treatment in the synthesis process, which also includes saccharification and fermentation. By collecting scientific data from the available literature, we conducted a comprehensive life cycle analysis. Our findings revealed substantial differences in the environmental burdens associated with diverse pre-treatment methods used for lignocellulosic biomass. These results highlight the importance of selecting environmentally benign pre-treatment techniques to promote the sustainability of bioethanol production. Future research directions are suggested, emphasizing the optimization of pre-treatment processes to further mitigate their environmental impact.
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Affiliation(s)
- Alice Jasmine David
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur, Chennai, 603203 India
| | - Sudharsanam Abinandan
- Global Centre for Environmental Remediation, University of Newcastle, Callaghan, NSW 2308 Australia
| | - Vinoth Kumar Vaidyanathan
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur, Chennai, 603203 India
| | - Chunbao Charles Xu
- Department of Chemical and Biochemical Engineering, Western University, London, ON N6A 5B9 Canada
| | - Tamilarasan Krishnamurthi
- Department of Chemical Engineering, SRM Institute of Science and Technology, Kattankulathur, Chennai, Tamil Nadu 603203 India
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Caputo F, Tõlgo M, Naidjonoka P, Krogh KBRM, Novy V, Olsson L. Investigating the role of AA9 LPMOs in enzymatic hydrolysis of differentially steam-pretreated spruce. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:68. [PMID: 37076886 PMCID: PMC10114483 DOI: 10.1186/s13068-023-02316-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 03/31/2023] [Indexed: 04/21/2023]
Abstract
BACKGROUND To realize the full potential of softwood-based forest biorefineries, the bottlenecks of enzymatic saccharification of softwood need to be better understood. Here, we investigated the potential of lytic polysaccharide monooxygenases (LPMO9s) in softwood saccharification. Norway spruce was steam-pretreated at three different severities, leading to varying hemicellulose retention, lignin condensation, and cellulose ultrastructure. Hydrolyzability of the three substrates was assessed after pretreatment and after an additional knife-milling step, comparing the efficiency of cellulolytic Celluclast + Novozym 188 and LPMO-containing Cellic CTec2 cocktails. The role of Thermoascus aurantiacus TaLPMO9 in saccharification was assessed through time-course analysis of sugar release and accumulation of oxidized sugars, as well as wide-angle X-ray scattering analysis of cellulose ultrastructural changes. RESULTS Glucose yield was 6% (w/w) with the mildest pretreatment (steam pretreatment at 210 °C without catalyst) and 66% (w/w) with the harshest (steam pretreatment at 210 °C with 3%(w/w) SO2) when using Celluclast + Novozym 188. Surprisingly, the yield was lower with all substrates when Cellic CTec2 was used. Therefore, the conditions for optimal LPMO activity were tested and it was found that enough O2 was present over the headspace and that the reducing power of the lignin of all three substrates was sufficient for the LPMOs in Cellic CTec2 to be active. Supplementation of Celluclast + Novozym 188 with TaLPMO9 increased the conversion of glucan by 1.6-fold and xylan by 1.5-fold, which was evident primarily in the later stages of saccharification (24-72 h). Improved glucan conversion could be explained by drastically reduced cellulose crystallinity of spruce substrates upon TaLPMO9 supplementation. CONCLUSION Our study demonstrated that LPMO addition to hydrolytic enzymes improves the release of glucose and xylose from steam-pretreated softwood substrates. Furthermore, softwood lignin provides enough reducing power for LPMOs, irrespective of pretreatment severity. These results provided new insights into the potential role of LPMOs in saccharification of industrially relevant softwood substrates.
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Affiliation(s)
- Fabio Caputo
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden
| | - Monika Tõlgo
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden
- Wallenberg Wood Science Center, Chalmers University of Technology, Kemigården 4, 412 96, Gothenburg, Sweden
| | - Polina Naidjonoka
- Wallenberg Wood Science Center, Chalmers University of Technology, Kemigården 4, 412 96, Gothenburg, Sweden
- Division of Materials Physics, Department of Physics, Chalmers University of Technology, Kemigården 1, 412 96, Gothenburg, Sweden
| | | | - Vera Novy
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden
- Wallenberg Wood Science Center, Chalmers University of Technology, Kemigården 4, 412 96, Gothenburg, Sweden
| | - Lisbeth Olsson
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden.
- Wallenberg Wood Science Center, Chalmers University of Technology, Kemigården 4, 412 96, Gothenburg, Sweden.
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Tang C, Gandla ML, Jönsson LJ. Comparison of solid and liquid fractions of pretreated Norway spruce as reductants in LPMO-supported saccharification of cellulose. Front Bioeng Biotechnol 2022; 10:1071159. [PMID: 36582841 PMCID: PMC9792786 DOI: 10.3389/fbioe.2022.1071159] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022] Open
Abstract
The role of lignin in enzymatic saccharification of cellulose involving lytic polysaccharide monooxygenase (LPMO) was investigated in experiments with the solid and liquid fractions of pretreated Norway spruce from a biorefinery demonstration plant using hydrothermal pretreatment and impregnation with sulfur dioxide. Pretreated biomass before and after enzymatic saccharification was characterized using HPAEC, HPLC, Py-GC/MS, 2D-HSQC NMR, FTIR, and SEM. Chemical characterization indicated that relatively harsh pretreatment conditions resulted in that the solid phase contained no or very little hemicellulose but considerable amounts of pseudo-lignin, and that the liquid phase contained a relatively high concentration (∼5 g/L) of lignin-derived phenolics. As judged from reactions continuously supplied with either air or nitrogen gas, lignin and lignin fragments from both the solid and the liquid phases efficiently served as reductants in LPMO-supported saccharification. When air was used to promote LPMO activity, the enzymatic conversion of cellulose after 72 h was 25% higher in reactions with pretreated solids and buffer, and 14% higher in reactions with pretreatment liquid and microcrystalline cellulose. Research in this area is useful for designing efficient saccharification steps in biochemical conversion of lignocellulosic biomass.
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Liu B, Liu L, Deng B, Huang C, Zhu J, Liang L, He X, Wei Y, Qin C, Liang C, Liu S, Yao S. Application and prospect of organic acid pretreatment in lignocellulosic biomass separation: A review. Int J Biol Macromol 2022; 222:1400-1413. [PMID: 36195224 DOI: 10.1016/j.ijbiomac.2022.09.270] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/20/2022] [Accepted: 09/28/2022] [Indexed: 11/28/2022]
Abstract
As a clean and efficient method of lignocellulosic biomass separation, organic acid pretreatment has attracted extensive research. Hemicellulose or lignin is selectively isolated and the cellulose structure is preserved. Effective fractionation of lignocellulosic biomass is achieved. The separation characteristics of hemicellulose or lignin by different organic acids were summarized. The organic acids of hemicellulose were separated into hydrogen ionized, autocatalytic and α-hydroxy acids according to the separation mechanism. The separation of lignin depends on the dissolution mechanism and spatial effect of organic acids. In addition, the challenges and prospects of organic acid pretreatment were analyzed. The separation of hemicellulose and enzymatic hydrolysis of cellulose were significantly affected by the polycondensation of lignin, which is effectively inhibited by the addition of green additives such as ketones or alcohols. Lignin separation was improved by developing a deep eutectic solvent treatment based on organic acid pretreatment. This work provides support for efficient cleaning of carbohydrate polymers and lignin to promote global carbon neutrality.
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Affiliation(s)
- Baojie Liu
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Lu Liu
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Baojuan Deng
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Caoxing Huang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, PR China
| | - Jiatian Zhu
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Linlin Liang
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Xinliang He
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Yuxin Wei
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Chengrong Qin
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China.
| | - Chen Liang
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China
| | - Shijie Liu
- Department of Paper and Bioprocess Engineering, SUNY College of Environmental Science and Forestry,1 Forestry Drive, Syracuse, NY 13210, United States
| | - Shuangquan Yao
- Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, PR China.
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7
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Momayez F, Hedenström M, Stagge S, Jönsson LJ, Martín C. Valorization of hydrolysis lignin from a spruce-based biorefinery by applying γ-valerolactone treatment. BIORESOURCE TECHNOLOGY 2022; 359:127466. [PMID: 35710049 DOI: 10.1016/j.biortech.2022.127466] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Hydrolysis lignin, i.e., the hydrolysis residue of cellulosic ethanol plants, was extracted with the green solvent γ-valerolactone (GVL). Treatments at 170-210 °C were performed with either non-acidified GVL/water mixtures (NA-GVL) or with mixtures containing sulfuric acid (SA-GVL). SA-GVL treatment at 210 °C resulted in the highest lignin solubilization (64% (w/w) of initial content), and 76% of the solubilized mass was regenerated by water-induced precipitation. Regenerated lignins were characterized through compositional analysis with sulfuric acid, as well as using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), high-performance size-exclusion chromatography (HPSEC), solid-state cross-polarization/magic angle spinning 13C nuclear magnetic resonance (CP/MAS 13C NMR) spectroscopy, 1H-13C heteronuclear single-quantum coherence NMR (HSQC NMR), and Fourier-transform infrared (FTIR) spectroscopy. The characterization revealed that the main difference between regenerated lignins was their molecular weight. Molecular weight averages increased with treatment temperature, and they were higher and had broader distribution for SA-GVL lignins than for NA-GVL lignins.
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Affiliation(s)
- Forough Momayez
- Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden
| | | | - Stefan Stagge
- Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden
| | - Leif J Jönsson
- Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden
| | - Carlos Martín
- Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden; Inland Norway University of Applied Sciences, Department of Biotechnology, N-2317 Hamar, Norway.
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Chen F, Xiong S, Latha Gandla M, Stagge S, Martín C. Spent mushroom substrates for ethanol production - Effect of chemical and structural factors on enzymatic saccharification and ethanolic fermentation of Lentinula edodes-pretreated hardwood. BIORESOURCE TECHNOLOGY 2022; 347:126381. [PMID: 34813922 DOI: 10.1016/j.biortech.2021.126381] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
Spent mushroom substrates (SMS) from cultivation of shiitake (Lentinula edodes) on three hardwood species were investigated regarding their potential for cellulose saccharification and for ethanolic fermentation of the produced hydrolysates. High glucan digestibility was achieved during enzymatic saccharification of the SMSs, which was related to the low mass fractions of lignin and xylan, and it was neither affected by the relative content of lignin guaiacyl units nor the substrate crystallinity. The high nitrogen content in SMS hydrolysates, which was a consequence of the fungal pretreatment, was positive for the fermentation, and it ensured ethanol yields corresponding to 84-87% of the theoretical value in fermentations without nutrient supplementation. Phenolic compounds and acetic acid were detected in the SMS hydrolysates, but due to their low concentrations, the inhibitory effect was limited. The solid leftovers resulting from SMS hydrolysis and the fermentation residues were quantified and characterized for further valorisation.
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Affiliation(s)
- Feng Chen
- Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden.
| | - Shaojun Xiong
- Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden
| | | | - Stefan Stagge
- Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden
| | - Carlos Martín
- Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden; Inland Norway University of Applied Sciences, Department of Biotechnology, N-2317 Hamar, Norway
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9
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Martín C, Dixit P, Momayez F, Jönsson LJ. Hydrothermal Pretreatment of Lignocellulosic Feedstocks to Facilitate Biochemical Conversion. Front Bioeng Biotechnol 2022; 10:846592. [PMID: 35252154 PMCID: PMC8888528 DOI: 10.3389/fbioe.2022.846592] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 01/24/2022] [Indexed: 11/27/2022] Open
Abstract
Biochemical conversion of lignocellulosic feedstocks to advanced biofuels and other bio-based commodities typically includes physical diminution, hydrothermal pretreatment, enzymatic saccharification, and valorization of sugars and hydrolysis lignin. This approach is also known as a sugar-platform process. The goal of the pretreatment is to facilitate the ensuing enzymatic saccharification of cellulose, which is otherwise impractical due to the recalcitrance of lignocellulosic feedstocks. This review focuses on hydrothermal pretreatment in comparison to alternative pretreatment methods, biomass properties and recalcitrance, reaction conditions and chemistry of hydrothermal pretreatment, methodology for characterization of pretreatment processes and pretreated materials, and how pretreatment affects subsequent process steps, such as enzymatic saccharification and microbial fermentation. Biochemical conversion based on hydrothermal pretreatment of lignocellulosic feedstocks has emerged as a technology of high industrial relevance and as an area where advances in modern industrial biotechnology become useful for reducing environmental problems and the dependence on fossil resources.
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Affiliation(s)
- Carlos Martín
- Department of Chemistry, Umeå University, Umeå, Sweden
- Department of Biotechnology, Inland Norway University of Applied Sciences, Hamar, Norway
| | - Pooja Dixit
- Department of Chemistry, Umeå University, Umeå, Sweden
| | | | - Leif J. Jönsson
- Department of Chemistry, Umeå University, Umeå, Sweden
- *Correspondence: Leif J. Jönsson,
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Li M, Fang A, Yu X, Zhang K, He Z, Wang C, Peng Y, Xiao F, Yang T, Zhang W, Zheng X, Zhong Q, Liu X, Yan Q. Microbially-driven sulfur cycling microbial communities in different mangrove sediments. CHEMOSPHERE 2021; 273:128597. [PMID: 33077194 DOI: 10.1016/j.chemosphere.2020.128597] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 05/13/2023]
Abstract
Microbially-driven sulfur cycling is a vital biogeochemical process in the sulfur-rich mangrove ecosystem. It is critical to evaluate the potential impact of sulfur transformation in mangrove ecosystems. To reveal the diversity, composition, and structure of sulfur-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) and underlying mechanisms, we analyzed the physicochemical properties and sediment microbial communities from an introduced mangrove species (Sonneratia apetala), a native mangrove species (Kandelia obovata) and the mudflat in Hanjiang River Estuary in Guangdong (23.27°N, 116.52°E), China. The results indicated that SOB was dominated by autotrophic Thiohalophilus and chemoautotrophy Chromatium in S. apetala and K. obovata, respectively, while Desulfatibacillum was the dominant genus of SRB in K. obovata sediments. Also, the redundancy analysis indicated that temperature, redox potential (ORP), and SO42- were the significant factors influencing the sulfur cycling microbial communities with elemental sulfur (ES) as the key factor driver for SOB and total carbon (TC) for SRB in mangrove sediments. Additionally, the morphological transformation of ES, acid volatile sulfide (AVS) and SO42- explained the variation of sulfur cycling microbial communities under sulfur-rich conditions, and we found mangrove species-specific dominant Thiohalobacter, Chromatium and Desulfatibacillum, which could well use ES and SO42-, thus promoting the sulfur cycling in mangrove sediments. Meanwhile, the change of nutrient substances (TN, TC) explained why SOB were more susceptible to environmental changes than SRB. Sulfate reducing bacteria produces sulfide in anoxic sediments at depth that then migrate upward, toward fewer reducing conditions, where it's oxidized by sulfur oxidizing bacteria. This study indicates the high ability of SOB and SRB in ES, SO42-,S2- and S2- generation and transformation in sulfur-rich mangrove ecosystems, and provides novel insights into sulfur cycling in other wetland ecosystems from a microbial perspective.
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Affiliation(s)
- Mingyue Li
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Anqi Fang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Xiaoli Yu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Keke Zhang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Zhili He
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China; College of Agronomy, Hunan Agricultural University, Changsha, 410128, China
| | - Cheng Wang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Yisheng Peng
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Fanshu Xiao
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China.
| | - Tony Yang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Wei Zhang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Xiafei Zheng
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Qiuping Zhong
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Xingyu Liu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China
| | - Qingyun Yan
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, 510006, China.
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11
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Sinitsyn AP, Sinitsyna OA. Bioconversion of Renewable Plant Biomass. Second-Generation Biofuels: Raw Materials, Biomass Pretreatment, Enzymes, Processes, and Cost Analysis. BIOCHEMISTRY (MOSCOW) 2021; 86:S166-S195. [PMID: 33827407 DOI: 10.1134/s0006297921140121] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The review discusses various aspects of renewable plant biomass conversion and production of the second-generation biofuels, including the types of plant biomass, its composition and reaction ability in the enzymatic hydrolysis, and various pretreatment methods for increasing the biomass reactivity. Conversion of plant biomass into sugars requires the use of a complex of enzymes, the composition of which should be adapted to the biomass type and the pretreatment method. The efficiency of enzymatic hydrolysis can be increased by optimizing the composition of the enzymatic complex and by increasing the catalytic activity and operational stability of its constituent enzymes. The availability of active enzyme producers also plays an important role. Examples of practical implementation and scaling of processes for the production of second-generation biofuels are presented together with the cost analysis of bioethanol production.
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Affiliation(s)
- Arkadij P Sinitsyn
- Bakh Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow, 119071, Russia. .,Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Olga A Sinitsyna
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
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12
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Factors Affecting Detoxification of Softwood Enzymatic Hydrolysates Using Sodium Dithionite. Processes (Basel) 2021. [DOI: 10.3390/pr9050887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Conditioning of lignocellulosic hydrolysates with sulfur oxyanions, such as dithionite, is one of the most potent methods to improve the fermentability by counteracting effects of inhibitory by-products generated during hydrothermal pretreatment under acidic conditions. The effects of pH, treatment temperature, and dithionite dosage were explored in experiments with softwood hydrolysates, sodium dithionite, and Saccharomyces cerevisiae yeast. Treatments with dithionite at pH 5.5 or 8.5 gave similar results with regard to ethanol productivity and yield on initial glucose, and both were always at least ~20% higher than for treatment at pH 2.5. Experiments in the dithionite concentration range 5.0–12.5 mM and the temperature range 23–110 °C indicated that treatment at around 75 °C and using intermediate dithionite dosage was the best option (p ≤ 0.05). The investigation indicates that selection of the optimal temperature and dithionite dosage offers great benefits for the efficient fermentation of hydrolysates from lignin-rich biomass, such as softwood residues.
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13
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Extended fed-batch fermentation of a C5/C6 optimised yeast strain on wheat straw hydrolysate using an online refractive index sensor to measure the relative fermentation rate. Sci Rep 2020; 10:6705. [PMID: 32317712 PMCID: PMC7174321 DOI: 10.1038/s41598-020-63626-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/18/2020] [Indexed: 02/06/2023] Open
Abstract
In the production of 2nd generation ethanol, using Saccharomyces cerevisiae, the highest productivity obtained using C5/C6 fermenting yeast is in the co-fermentation phase, in which xylose and glucose are fermented simultaneously. Extending this phase in a fed-batch process increases the yield, rate and additionally reduces needed yeast amount for pitching. Extending this phase, as long as possible, would further enhance yield and economy of the process. To realise the concept a fermentation monitoring technique was developed and applied. Based on online measured refractive index an optimal residual sugar concentration could be maintained in the primary fermentor during the feed phase, requiring little knowledge of the nature of the substrate. The system was able to run stably for at least five fermentor volumes giving an ethanol yield >90% throughout the run. This was achieved with addition of only urea to the wheat straw hydrolysate and with an initial yeast pitch of 0.2 g/L total of finished broth. It has the potential to improve the fermentation technology used in fuel ethanol plants, which could help to meet the growing demand for more sustainable fuels.
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15
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Peinemann JC, Pleissner D. Continuous pretreatment, hydrolysis, and fermentation of organic residues for the production of biochemicals. BIORESOURCE TECHNOLOGY 2020; 295:122256. [PMID: 31645308 DOI: 10.1016/j.biortech.2019.122256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
Agricultural residues pose a valuable resource. Through microbial fermentations, a variety of products can be obtained, ranging from fuels to platform chemicals. Depending on the nature of the organic residue, pretreatment and hydrolysis are needed prior to fermentation in order to release fermentable sugars. Continuous set-ups are common for the production of methane or ethanol from lignocellulosic biomass, however, this does not apply for the fermentative generation of biochemicals, an approach that conserves chemical functionality present in biomass. Certainly, continuous set-ups could beneficially contribute to bioeconomy by providing techniques allowing the production of biochemicals in a sustainable and efficient way. This review summarizes research conducted on the continuous pretreatment, hydrolysis, and fermentation of lignocellulosic biomass, and particularly towards the production of the biobased molecules: Succinic and lactic acid.
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Affiliation(s)
- Jan Christoph Peinemann
- Sustainable Chemistry (Resource Efficiency), Institute of Sustainable and Environmental Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, C13.203, Lüneburg 21335, Germany
| | - Daniel Pleissner
- Sustainable Chemistry (Resource Efficiency), Institute of Sustainable and Environmental Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, C13.203, Lüneburg 21335, Germany; Institute for Food and Environmental Research e.V., Papendorfer Weg 3, Bad Belzig 14806, Germany.
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16
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Lee CL, H'ng PS, Chin KL, Paridah MT, Rashid U, Go WZ. Characterization of bioadsorbent produced using incorporated treatment of chemical and carbonization procedures. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190667. [PMID: 31598301 PMCID: PMC6774958 DOI: 10.1098/rsos.190667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
The production of bioadsorbent from palm kernel shell (PKS) and coconut shell (CS) pretreated with 30% phosphoric acid (H3PO4) was optimized using the response surface methodology (RSM). Iodine adsorption for both bioadsorbents was optimized by central composite design. Two parameters including the H3PO4 pretreatment temperature and carbonization temperature were determined as significant factors to improve the iodine adsorption of the bioadsorbent. Statistical analysis results divulge that both factors had significant effect on the iodine adsorption for the bioadsorbent. From the RSM analysis, it was suggested that using 80 and 79°C as H3PO4 pretreatment temperature and 714 and 715°C as carbonization temperature would enhance the iodine adsorption of the CS and PKS bioadsobent, respectively. These results indicated that H3PO4 is a good pretreatment for preparing PKS and CS prior to carbonization process to produce bioadsorbent with well-developed microporous and mesoporous volume. The effort to produce alternative high grade and inexpensive adsorbent derived from lignocellulosic biomass, particularly in the nut shell form was implied in this research.
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Affiliation(s)
- Chuan Li Lee
- Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Paik San H'ng
- Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
- Faculty of Forestry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Kit Ling Chin
- Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Md Tahir Paridah
- Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
- Faculty of Forestry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Umer Rashid
- Institute of Advance Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - Wen Ze Go
- Faculty of Forestry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
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Matsakas L, Raghavendran V, Yakimenko O, Persson G, Olsson E, Rova U, Olsson L, Christakopoulos P. Lignin-first biomass fractionation using a hybrid organosolv - Steam explosion pretreatment technology improves the saccharification and fermentability of spruce biomass. BIORESOURCE TECHNOLOGY 2019; 273:521-528. [PMID: 30471644 DOI: 10.1016/j.biortech.2018.11.055] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/13/2018] [Accepted: 11/14/2018] [Indexed: 05/05/2023]
Abstract
For a transition to a sustainable society, fuels, chemicals, and materials should be produced from renewable resources. Lignocellulosic biomass constitutes an abundant and renewable feedstock; however, its successful application in a biorefinery requires efficient fractionation into its components; cellulose, hemicellulose and lignin. Here, we demonstrate that a newly established hybrid organosolv - steam explosion pretreatment can effectively fractionate spruce biomass to yield pretreated solids with high cellulose (72% w/w) and low lignin (delignification up to 79.4% w/w) content. The cellulose-rich pretreated solids present high saccharification yields (up to 61% w/w) making them ideal for subsequent bioconversion processes. Moreover, under high-gravity conditions (22% w/w) we obtained an ethanol titer of 61.7 g/L, the highest so far reported for spruce biomass. Finally, the obtained high-purity lignin is suitable for various advanced applications. In conclusion, hybrid organosolv pretreatment could offer a closed-loop biorefinery while simultaneously adding value to all biomass components.
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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
| | - Vijayendran Raghavendran
- Chalmers University of Technology, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Kemivägen 10, SE-412 96 Göteborg, Sweden
| | - 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
- Chalmers University of Technology, Department of Physics, Fysikgränd 3, Göteborg SE-412 96, Sweden
| | - Eva Olsson
- Chalmers University of Technology, Department of Physics, Fysikgränd 3, Göteborg SE-412 96, 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
- Chalmers University of Technology, Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Kemivägen 10, SE-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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18
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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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Analytical Enzymatic Saccharification of Lignocellulosic Biomass for Conversion to Biofuels and Bio-Based Chemicals. ENERGIES 2018. [DOI: 10.3390/en11112936] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lignocellulosic feedstocks are an important resource for biorefining of renewables to bio-based fuels, chemicals, and materials. Relevant feedstocks include energy crops, residues from agriculture and forestry, and agro-industrial and forest-industrial residues. The feedstocks differ with respect to their recalcitrance to bioconversion through pretreatment and enzymatic saccharification, which will produce sugars that can be further converted to advanced biofuels and other products through microbial fermentation processes. In analytical enzymatic saccharification, the susceptibility of lignocellulosic samples to pretreatment and enzymatic saccharification is assessed in analytical scale using high-throughput or semi-automated techniques. This type of analysis is particularly relevant for screening of large collections of natural or transgenic varieties of plants that are dedicated to production of biofuels or other bio-based chemicals. In combination with studies of plant physiology and cell wall chemistry, analytical enzymatic saccharification can provide information about the fundamental reasons behind lignocellulose recalcitrance as well as about the potential of collections of plants or different fractions of plants for industrial biorefining. This review is focused on techniques used by researchers for screening the susceptibility of plants to pretreatment and enzymatic saccharification, and advantages and disadvantages that are associated with different approaches.
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Donev E, Gandla ML, Jönsson LJ, Mellerowicz EJ. Engineering Non-cellulosic Polysaccharides of Wood for the Biorefinery. FRONTIERS IN PLANT SCIENCE 2018; 9:1537. [PMID: 30405672 PMCID: PMC6206411 DOI: 10.3389/fpls.2018.01537] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/28/2018] [Indexed: 05/10/2023]
Abstract
Non-cellulosic polysaccharides constitute approximately one third of usable woody biomass for human exploitation. In contrast to cellulose, these substances are composed of several different types of unit monosaccharides and their backbones are substituted by various groups. Their structural diversity and recent examples of their modification in transgenic plants and mutants suggest they can be targeted for improving wood-processing properties, thereby facilitating conversion of wood in a biorefinery setting. Critical knowledge on their structure-function relationship is slowly emerging, although our understanding of molecular interactions responsible for observed phenomena is still incomplete. This review: (1) provides an overview of structural features of major non-cellulosic polysaccharides of wood, (2) describes the fate of non-cellulosic polysaccharides during biorefinery processing, (3) shows how the non-cellulosic polysaccharides impact lignocellulose processing focused on yields of either sugars or polymers, and (4) discusses outlooks for the improvement of tree species for biorefinery by modifying the structure of non-cellulosic polysaccharides.
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Affiliation(s)
- Evgeniy Donev
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | | | - Ewa J. Mellerowicz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
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21
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Martín C, Wu G, Wang Z, Stagge S, Jönsson LJ. Formation of microbial inhibitors in steam-explosion pretreatment of softwood impregnated with sulfuric acid and sulfur dioxide. BIORESOURCE TECHNOLOGY 2018; 262:242-250. [PMID: 29709843 DOI: 10.1016/j.biortech.2018.04.074] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/17/2018] [Accepted: 04/18/2018] [Indexed: 05/08/2023]
Abstract
Wood chips of Norway spruce were pretreated by steam explosion at 195-215 °C after impregnation with either sulfuric acid (SA) or sulfur dioxide (SD). The effects of different pretreatment conditions on formation of microbial inhibitors were investigated, and the inhibitory effects on yeast of pretreatment liquids and of specific inhibitors that were found in the pretreatment liquids were elucidated. Whereas the concentrations of most inhibitors increased with increasing pretreatment temperatures, there were exceptions, such as formaldehyde and p-hydroxybenzaldehyde. The highest concentration of each inhibitor was typically found in SD-pretreated material, but formic acid was an exception. The toxic effects on yeast were studied using concentrations corresponding to loadings of 12 and 20% total solids (TS). Among individual inhibitors that were quantitated in pretreatment liquids, the concentrations of formaldehyde were by far most toxic. There was no or minimal yeast growth in the formaldehyde concentration range (5.8-7.7 mM) corresponding to 12% TS.
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Affiliation(s)
- Carlos Martín
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Guochao Wu
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Zhao Wang
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Stefan Stagge
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
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