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Paz A, Karnaouri A, Templis CC, Papayannakos N, Topakas E. Valorization of exhausted olive pomace for the production of omega-3 fatty acids by Crypthecodinium cohnii. WASTE MANAGEMENT (NEW YORK, N.Y.) 2020; 118:435-444. [PMID: 32971378 DOI: 10.1016/j.wasman.2020.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
Exhausted olive pomace (EOP) represents a potential candidate side stream to be utilized in biotechnological processes. EOP composition includes significant amounts of extractives and pectin, which are both usually discarded and are not utilized in the valorization process of the raw material. In this study, organosolv technology was optimized to remove the extractives and pectin using a Central Composite Rotatable Design. Optimal pretreatment conditions were predicted to be at 97.95 °C for 23.18 min, upon addition of 50% (v/v) EtOH in H2O, with 0.5% (w/v) of H2SO4 as catalyst. The composition analysis of liquid fraction revealed a high content of total sugars (17.58 g/L), galacturonic acid (7.05 g/L) and phenolic compounds (2.97 g/L). The liquid fraction was utilized as a carbon source by the heterotrophic marine microalgae Crypthecodinium cohnii, where it was shown to promote lipid accumulation up to 38.5% wt. of cell biomass, even without any additional detoxification step. This study is the first report that shows the use of galacturonic acid as carbon source for the growth of C. cohnii, while underpinning the use of EOP as a promising substrate for the development of zero-waste bioprocesses.
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Affiliation(s)
- Alicia Paz
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece; Industrial Biotechnology and Environmental Engineering Group "BiotecnIA", Chemical Engineering Department, University of Vigo (Campus Ourense), As Lagoas s/n, 32004 Ourense, Galicia, Spain
| | - Anthi Karnaouri
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece
| | - Chrysovalantis C Templis
- Chemical Process Engineering Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece
| | - Nikolaos Papayannakos
- Chemical Process Engineering Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece
| | - Evangelos Topakas
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece.
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2
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Kline LM, Voothuluru P, Lenaghan SC, Burris JN, Soliman M, Tetard L, Stewart CN, Rials TG, Labbé N. A Robust Method to Quantify Cell Wall Bound Phenolics in Plant Suspension Culture Cells Using Pyrolysis-Gas Chromatography/Mass Spectrometry. FRONTIERS IN PLANT SCIENCE 2020; 11:574016. [PMID: 33013999 PMCID: PMC7509179 DOI: 10.3389/fpls.2020.574016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/18/2020] [Indexed: 06/11/2023]
Abstract
The wide-scale production of renewable fuels from lignocellulosic feedstocks continues to be hampered by the natural recalcitrance of biomass. Therefore, there is a need to develop robust and reliable methods to characterize and quantify components that contribute to this recalcitrance. In this study, we utilized a method that incorporates pyrolysis with successive gas chromatography and mass spectrometry (Py-GC/MS) to assess lignification in cell suspension cultures. This method was compared with other standard techniques such as acid-catalyzed hydrolysis, acetyl bromide lignin determination, and nitrobenzene oxidation for quantification of cell wall bound phenolic compounds. We found that Py-GC/MS can be conducted with about 250 µg of tissue sample and provides biologically relevant data, which constitutes a substantial advantage when compared to the 50-300 mg of tissue needed for the other methods. We show that when combined with multivariate statistical analyses, Py-GC/MS can distinguish cell wall components of switchgrass (Panicum virgatum) suspension cultures before and after inducing lignification. The deposition of lignin precursors on uninduced cell walls included predominantly guaiacyl-based units, 71% ferulic acid, and 5.3% p-coumaric acid. Formation of the primary and partial secondary cell wall was supported by the respective ~15× and ~1.7× increases in syringyl-based and guaiacyl-based precursors, respectively, in the induced cells. Ferulic acid was decreased by half after induction. These results provide the proof-of-concept for quick and reliable cell wall compositional analyses using Py-GC/MS and could be targeted for either translational genomics or for fundamental studies focused on understanding the molecular and physiological mechanisms regulating plant cell wall production and biomass recalcitrance.
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Affiliation(s)
- Lindsey M. Kline
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
| | - Priya Voothuluru
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
| | - Scott C. Lenaghan
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
- Department of Food Science, University of Tennessee, Knoxville, TN, United States
- Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - Jason N. Burris
- Department of Food Science, University of Tennessee, Knoxville, TN, United States
- Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, United States
| | - Mikhael Soliman
- Nanoscience Technology Center, Department of Physics, University of Central Florida, Orlando, FL, United States
| | - Laurene Tetard
- Nanoscience Technology Center, Department of Physics, University of Central Florida, Orlando, FL, United States
| | - C. Neal Stewart
- Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, United States
| | - Timothy G. Rials
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
| | - Nicole Labbé
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
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van der Zwan T, Sigg A, Hu J, Chandra RP, Saddler JN. Enzyme-Mediated Lignocellulose Liquefaction Is Highly Substrate-Specific and Influenced by the Substrate Concentration or Rheological Regime. Front Bioeng Biotechnol 2020; 8:917. [PMID: 32850753 PMCID: PMC7423843 DOI: 10.3389/fbioe.2020.00917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 07/16/2020] [Indexed: 01/30/2023] Open
Abstract
The high viscosities/yield stresses of lignocellulose slurries makes their industrial processing a significant challenge. However, little is known regarding the degree to which liquefaction and its enzymatic requirements are specific to a substrate's physicochemical and rheological properties. In the work reported here, the substrate- and rheological regime-specificities of liquefaction of various substrates were assessed using real-time in-rheometer viscometry and offline oscillatory rheometry when hydrolyzed by combinations of cellobiohydrolase (Trichoderma reesei Cel7A), endoglucanase (Humicola insolens Cel45A), glycoside hydrolase (GH) family 10 xylanase, and GH family 11 xylanase. In contrast to previous work that has suggested that endoglucanase activity dominates enzymatic liquefaction, all of the enzymes were shown to have at least some liquefaction capacity depending on the substrate and reaction conditions. The contribution of individual enzymes was found to be influenced by the rheological regime; in the concentrated regime, the cellobiohydrolase outperformed the endoglucanase, achieving 2.4-fold higher yield stress reduction over the same timeframe, whereas the endoglucanase performed best in the semi-dilute regime. It was apparent that the significant differences in rheology and liquefaction mechanisms made it difficult to predict the liquefaction capacity of an enzyme or enzyme cocktail at different substrate concentrations.
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Affiliation(s)
- Timo van der Zwan
- Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, Vancouver, BC, Canada
| | - Alexander Sigg
- Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, Vancouver, BC, Canada
- Department of Chemistry, Technical University of Munich, Munich, Germany
| | - Jinguang Hu
- Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, Vancouver, BC, Canada
| | - Richard P. Chandra
- Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, Vancouver, BC, Canada
| | - Jack N. Saddler
- Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, Vancouver, BC, Canada
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Influence of Base-Catalyzed Organosolv Fractionation of Larch Wood Sawdust on Fraction Yields and Lignin Properties. Catalysts 2019. [DOI: 10.3390/catal9120996] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Lignocellulose-based biorefineries are considered to play a crucial role in reducing fossil-fuel dependency. As of now, the fractionation is still the most difficult step of the whole process. The objective of this study is to investigate the potential of a base-catalyzed organosolv process as a fractionation technique for European larch sawdust. A solvent system comprising methanol, water, sodium hydroxide as catalyst, and anthraquinone as co-catalyst is tested. The influence of three independent process variables, temperature (443–446 K), catalyst loading (20–30% w/w), and alcohol-to-water ratio (30–70% v/v), is studied. The process conditions were determined using a fractional factorial experiment. One star point (443 K, 30% v/v MeOH, 30% w/w NaOH) resulted in the most promising results, with a cellulose recovery of 89%, delignification efficiency of 91%, pure lignin yield of 82%, residual carbohydrate content of 2.98% w/w, and an ash content of 1.24% w/w. The isolated lignin fractions show promising glass transition temperatures (≥424 K) with high thermal stabilities and preferential O/C and H/C ratios. This, together with high contents of phenolic hydroxyl (≥1.83 mmol/g) and carboxyl groups (≥0.52 mmol/g), indicates a high valorization potential. Additionally, Bjorkman lignin was isolated, and two reference Kraft cooks and a comparison to three acid-catalyzed organosolv fractionations were conducted.
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5
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Detailed Componential Characterization of Extractable Species with Organic Solvents from Wheat Straw. Int J Anal Chem 2017; 2017:7305682. [PMID: 29209369 PMCID: PMC5676445 DOI: 10.1155/2017/7305682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/25/2017] [Accepted: 09/18/2017] [Indexed: 11/17/2022] Open
Abstract
Componential analysis of extractives is important for better understanding the structure and utilization of biomass. In this investigation, wheat straw (WS) was extracted with petroleum ether (PE) and carbon disulfide (CS2) sequentially, to afford extractable fractions EFPE and EFCS2, respectively. Detailed componential analyses of EFPE and EFCS2 were carried out with Fourier transform infrared (FTIR) spectroscopy, gas chromatography/mass spectrometry (GC/MS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), and electron probe microanalysis (EPMA). Total extractives were quantified 4.96% by weight compared to the initial WS sample. FTIR and GC/MS analyses results showed that PE was effective for the extraction of ketones and waxes derived compounds; meanwhile CS2 preferred ketones and other species with higher degrees of unsaturation. Steroids were enriched into EFPE and EFCS2 with considerable high relative contents, namely, 64.52% and 79.58%, respectively. XPS analysis showed that most of the C atoms in extractives were contained in the structures of C-C, C-COOR, and C-O. TEM-EDS and EPMA analyses were used to detect trace amount elements, such as Al, Si, P, S, Cl, and Ca atoms. Detailed characterization of extractable species from WS can provide more information on elucidation of extractives in biomass.
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Sakai K, Kojiya S, Kamijo J, Tanaka Y, Tanaka K, Maebayashi M, Oh JS, Ito M, Hori M, Shimizu M, Kato M. Oxygen-radical pretreatment promotes cellulose degradation by cellulolytic enzymes. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:290. [PMID: 29213329 PMCID: PMC5713004 DOI: 10.1186/s13068-017-0979-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 11/26/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The efficiency of cellulolytic enzymes is important in industrial biorefinery processes, including biofuel production. Chemical methods, such as alkali pretreatment, have been extensively studied and demonstrated as effective for breaking recalcitrant lignocellulose structures. However, these methods have a detrimental effect on the environment. In addition, utilization of these chemicals requires alkali- or acid-resistant equipment and a neutralization step. RESULTS Here, a radical generator based on non-thermal atmospheric pressure plasma technology was developed and tested to determine whether oxygen-radical pretreatment enhances cellulolytic activity. Our results showed that the viscosity of carboxymethyl cellulose (CMC) solutions was reduced in a time-dependent manner by oxygen-radical pretreatment using the radical generator. Compared with non-pretreated CMC, oxygen-radical pretreatment of CMC significantly increased the production of reducing sugars in culture supernatant containing various cellulases from Phanerochaete chrysosporium. The production of reducing sugar from oxygen-radical-pretreated CMC by commercially available cellobiohydrolases I and II was 1.7- and 1.6-fold higher, respectively, than those from non-pretreated and oxygen-gas-pretreated CMC. Moreover, the amount of reducing sugar from oxygen-radical-pretreated wheat straw was 1.8-fold larger than those from non-pretreated and oxygen-gas-pretreated wheat straw. CONCLUSIONS Oxygen-radical pretreatment of CMC and wheat straw enhanced the degradation of cellulose by reducing- and non-reducing-end cellulases in the supernatant of a culture of the white-rot fungus P. chrysosporium. These findings indicated that oxygen-radical pretreatment of plant biomass offers great promise for improvements in lignocellulose-deconstruction processes.
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Affiliation(s)
- Kiyota Sakai
- Faculty of Agriculture, Meijo University, Nagoya, Aichi 468-8502 Japan
| | - Saki Kojiya
- Faculty of Agriculture, Meijo University, Nagoya, Aichi 468-8502 Japan
| | - Junya Kamijo
- Faculty of Agriculture, Meijo University, Nagoya, Aichi 468-8502 Japan
| | - Yuta Tanaka
- Faculty of Science and Technology, Meijo University, Nagoya, Aichi 468-8502 Japan
| | - Kenta Tanaka
- Faculty of Agriculture, Meijo University, Nagoya, Aichi 468-8502 Japan
| | | | - Jun-Seok Oh
- Faculty of Science and Technology, Meijo University, Nagoya, Aichi 468-8502 Japan
| | - Masafumi Ito
- Faculty of Science and Technology, Meijo University, Nagoya, Aichi 468-8502 Japan
| | - Masaru Hori
- Institute of Innovation for Future Society, Nagoya University, Nagoya, Aichi 464-8603 Japan
| | - Motoyuki Shimizu
- Faculty of Agriculture, Meijo University, Nagoya, Aichi 468-8502 Japan
| | - Masashi Kato
- Faculty of Agriculture, Meijo University, Nagoya, Aichi 468-8502 Japan
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7
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Removal of Water-Soluble Extractives Improves the Enzymatic Digestibility of Steam-Pretreated Softwood Barks. Appl Biochem Biotechnol 2017; 184:599-615. [PMID: 28808883 PMCID: PMC5767193 DOI: 10.1007/s12010-017-2577-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/02/2017] [Indexed: 11/25/2022]
Abstract
Softwood bark contains a large amounts of extractives—i.e., soluble lipophilic (such as resin acids) and hydrophilic components (phenolic compounds, stilbenes). The effects of the partial removal of water-soluble extractives before acid-catalyzed steam pretreatment on enzymatic digestibility were assessed for two softwood barks—Norway spruce and Scots pine. A simple hot water extraction step removed more than half of the water-soluble extractives from the barks, which improved the enzymatic digestibility of both steam-pretreated materials. This effect was more pronounced for the spruce than the pine bark, as evidenced by the 30 and 11% glucose yield improvement, respectively, in the enzymatic digestibility. Furthermore, analysis of the chemical composition showed that the acid-insoluble lignin content of the pretreated materials decreased when water-soluble extractives were removed prior to steam pretreatment. This can be explained by a decreased formation of water-insoluble “pseudo-lignin” from water-soluble bark phenolics during the acid-catalyzed pretreatment, which otherwise results in distorted lignin analysis and may also contribute to the impaired enzymatic digestibility of the barks. Thus, this study advocates the removal of extractives as the first step in the processing of bark or bark-rich materials in a sugar platform biorefinery.
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8
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Pielhop T, Amgarten J, Studer MH, von Rohr PR. Pilot-scale steam explosion pretreatment with 2-naphthol to overcome high softwood recalcitrance. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:130. [PMID: 28529543 PMCID: PMC5437563 DOI: 10.1186/s13068-017-0816-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/02/2017] [Indexed: 05/11/2023]
Abstract
BACKGROUND Steam explosion pretreatment has been examined in many studies for enhancing the enzymatic digestibility of lignocellulosic biomass and is currently the most common pretreatment method in commercial biorefineries. It is however not effective for overcoming the extremely high recalcitrance of softwood to biochemical conversion. Recent fundamental research in small-scale liquid hot water pretreatment has shown, though, that the addition of a carbocation scavenger like 2-naphthol can prevent lignin repolymerization and thus enhance the enzymatic digestibility of softwood cellulose. This work studies the technical application potential of this approach in a larger steam explosion pilot plant for surmounting softwood recalcitrance. RESULTS The addition of 35.36 g 2-naphthol to the steam explosion pretreatment of 1.5 kg spruce wood chips allowed to considerably enhance the enzymatic cellulose digestibility. Different ways of adding the solid 2-naphthol to steam pretreatment were tested. Mixing with the biomass before pretreatment could enhance digestibility by up to 55% compared to control experiments. Impregnation of the biomass with 2-naphthol was yet more effective. Acetone and ethanol were tested to dissolve 2-naphthol and impregnate the biomass. The solvents were then removed again by evaporation before the pretreatment. The impregnation allowed to enhance digestibility by up to 179 and 192%, respectively. A comparison to prevalent acid-catalyzed steam explosion pretreatments for softwood revealed that the scavenger approach allows for obtaining exceptionally high yields in enzymatic hydrolysis. The biomass impregnation with 2-naphthol even renders a complete enzymatic cellulose conversion possible, which is remarkable for a softwood pretreatment not removing lignin. Steam pretreatment experiments without explosive decompression revealed that the enhancing effects of the explosion and the scavenger complement each other well. The explosion enhances the accessibility of the cellulose while the use of the scavenger reduces particularly the deactivation of enzymes. CONCLUSIONS This is the first study to show that a carbocation scavenger in steam pretreatment can enhance the enzymatic digestibility of lignocellulosic biomass. The approach opens up a novel possibility for overcoming the high softwood recalcitrance in a process that does not require an acid catalyst or the removal of lignin from the biomass.
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Affiliation(s)
- Thomas Pielhop
- Institute of Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland
| | - Janick Amgarten
- Institute of Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland
| | - Michael H. Studer
- School of Agricultural, Forest and Food Sciences, Bern University of Applied Sciences, Länggasse 85, 3052 Zollikofen, Switzerland
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Renders T, Schutyser W, Van den Bosch S, Koelewijn SF, Vangeel T, Courtin CM, Sels BF. Influence of Acidic (H3PO4) and Alkaline (NaOH) Additives on the Catalytic Reductive Fractionation of Lignocellulose. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02906] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tom Renders
- Center
for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan
200F, 3001 Leuven, Belgium
| | - Wouter Schutyser
- Center
for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan
200F, 3001 Leuven, Belgium
| | - Sander Van den Bosch
- Center
for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan
200F, 3001 Leuven, Belgium
| | - Steven-Friso Koelewijn
- Center
for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan
200F, 3001 Leuven, Belgium
| | - Thijs Vangeel
- Center
for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan
200F, 3001 Leuven, Belgium
| | - Christophe M. Courtin
- Center
for Food and Microbial Technology, KU Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - Bert F. Sels
- Center
for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan
200F, 3001 Leuven, Belgium
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10
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Shinya T, Iwata E, Nakahama K, Fukuda Y, Hayashi K, Nanto K, Rosa AC, Kawaoka A. Transcriptional Profiles of Hybrid Eucalyptus Genotypes with Contrasting Lignin Content Reveal That Monolignol Biosynthesis-related Genes Regulate Wood Composition. FRONTIERS IN PLANT SCIENCE 2016; 7:443. [PMID: 27148283 PMCID: PMC4829581 DOI: 10.3389/fpls.2016.00443] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/21/2016] [Indexed: 05/16/2023]
Abstract
Eucalyptus species constitutes the most widely planted hardwood trees in temperate and subtropical regions. In this study, we compared the transcript levels of genes involved in lignocellulose formation such as cellulose, hemicellulose and lignin biosynthesis in two selected 3-year old hybrid Eucalyptus (Eucalyptus urophylla × Eucalyptus grandis) genotypes (AM063 and AM380) that have different lignin content. AM063 and AM380 had 20.2 and 35.5% of Klason lignin content and 59.0 and 48.2%, α-cellulose contents, respectively. We investigated the correlation between wood properties and transcript levels of wood formation-related genes using RNA-seq with total RNAs extracted from developing xylem tissues at a breast height. Transcript levels of cell wall construction genes such as cellulose synthase (CesA) and sucrose synthase (SUSY) were almost the same in both genotypes. However, AM063 exhibited higher transcript levels of UDP-glucose pyrophosphorylase and xyloglucan endotransglucoxylase than those in AM380. Most monolignol biosynthesis-related isozyme genes showed higher transcript levels in AM380. These results indicate monolignol biosynthesis-related genes may regulate wood composition in Eucalyptus. Flavonoids contents were also observed at much higher levels in AM380 as a result of the elevated transcript levels of common phenylpropanoid pathway genes, phenylalanine ammonium lyase, cinnamate-4-hydroxylase (C4H) and 4-coumarate-CoA ligase (4CL). Secondary plant cell wall formation is regulated by many transcription factors. We analyzed genes encoding NAC, WRKY, AP2/ERF, and KNOX transcription factors and found higher transcript levels of these genes in AM380. We also observed increased transcription of some MYB and LIM domain transcription factors in AM380 compared to AM063. All these results show that genes related to monolignol biosynthesis may regulate the wood composition and help maintain the ratio of cellulose and lignin contents in Eucalyptus plants.
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Affiliation(s)
- Tomotaka Shinya
- Agri-Biotechnology Research Laboratory, Nippon Paper Industries Co., Ltd.Tokyo, Japan
| | - Eiji Iwata
- Agri-Biotechnology Research Laboratory, Nippon Paper Industries Co., Ltd.Tokyo, Japan
| | - Katsuhiko Nakahama
- Agri-Biotechnology Research Laboratory, Nippon Paper Industries Co., Ltd.Tokyo, Japan
| | - Yujiroh Fukuda
- Agri-Biotechnology Research Laboratory, Nippon Paper Industries Co., Ltd.Tokyo, Japan
| | - Kazunori Hayashi
- Forest Research Division, Amapa Frorestal e Celulose S.A.Santana, Brazil
| | - Kazuya Nanto
- Agri-Biotechnology Research Laboratory, Nippon Paper Industries Co., Ltd.Tokyo, Japan
| | - Antonio C. Rosa
- Forest Research Division, Amapa Frorestal e Celulose S.A.Santana, Brazil
| | - Akiyoshi Kawaoka
- Agri-Biotechnology Research Laboratory, Nippon Paper Industries Co., Ltd.Tokyo, Japan
- *Correspondence: Akiyoshi Kawaoka,
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11
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Karimi K, Taherzadeh MJ. A critical review of analytical methods in pretreatment of lignocelluloses: Composition, imaging, and crystallinity. BIORESOURCE TECHNOLOGY 2016; 200:1008-18. [PMID: 26614225 DOI: 10.1016/j.biortech.2015.11.022] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/07/2015] [Accepted: 11/09/2015] [Indexed: 05/02/2023]
Abstract
Lignocelluloses are widely investigated as renewable substrates to produce biofuels, e.g., ethanol, methane, hydrogen, and butanol, as well as chemicals such as citric acid, lactic acid, and xanthan gum. However, lignocelluloses have a recalcitrance structure to resist microbial and enzymatic attacks; therefore, many physical, thermal, chemical, and biological pretreatment methods have been developed to open up their structure. The efficiency of these pretreatments was studied using a variety of analytical methods that address their image, composition, crystallinity, degree of polymerization, enzyme adsorption/desorption, and accessibility. This paper presents a critical review of the first three categories of these methods as well as their constraints in various applications. The advantages, drawbacks, approaches, practical details, and some points that should be considered in the experimental methods to reach reliable and promising conclusions are also discussed.
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Affiliation(s)
- Keikhosro Karimi
- Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran; Industrial Biotechnology Group, Institute of Biotechnology and Bioengineering, Isfahan University of Technology, Isfahan 84156-83111, Iran
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12
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Fu L, McCallum SA, Miao J, Hart C, Tudryn GJ, Zhang F, Linhardt RJ. Rapid and accurate determination of the lignin content of lignocellulosic biomass by solid-state NMR. FUEL (LONDON, ENGLAND) 2015; 141:39-45. [PMID: 25404762 PMCID: PMC4231538 DOI: 10.1016/j.fuel.2014.10.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Biofuels and biomaterials, produced from lignocellulosic feedstock, require facile access to cellulose and hemicellulose to be competitive with petroleum processing and sugar-based fermentation. Physical-chemical barriers resulting from lignin complicates the hydrolysis biomass into fermentable sugars. Thus, the amount of lignin within a substrate is critical in determining biomass processing. The application of 13C cross-polarization, magic-angle spinning, and solid-state nuclear magnetic resonance for the direct quantification of lignin content in biomass is examined. Using a standard curve constructed from pristine lignin and cellulose, the lignin content of a biomass sample is accurately determined through direct measurement without chemical or enzymatic pre-treatment.
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Affiliation(s)
- Li Fu
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Scott A. McCallum
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Jianjun Miao
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Courtney Hart
- Ecovative Design, LLC, 70 Cohoes Ave, Green Island, New York 12183, USA
| | - Gregory J. Tudryn
- Ecovative Design, LLC, 70 Cohoes Ave, Green Island, New York 12183, USA
| | - Fuming Zhang
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Robert J. Linhardt
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
- Departments of Chemistry and Chemical Biology, Chemical and Biological Engineering, and Biology and Biomedical Engineering Rensselaer Polytechnic Institute, Troy, New York 12180, USA
- Corresponding author. Tel.: +1 518 276 3404; fax: +0-1 518 276 (R. Linhardt)
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Mafe OA, Davies SM, Hancock J, Du C. Development of an estimation model for the evaluation of the energy requirement of dilute acid pretreatments of biomass. BIOMASS & BIOENERGY 2015; 72:28-38. [PMID: 26109752 PMCID: PMC4461158 DOI: 10.1016/j.biombioe.2014.11.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 11/25/2014] [Accepted: 11/29/2014] [Indexed: 05/30/2023]
Abstract
This study aims to develop a mathematical model to evaluate the energy required by pretreatment processes used in the production of second generation ethanol. A dilute acid pretreatment process reported by National Renewable Energy Laboratory (NREL) was selected as an example for the model's development. The energy demand of the pretreatment process was evaluated by considering the change of internal energy of the substances, the reaction energy, the heat lost and the work done to/by the system based on a number of simplifying assumptions. Sensitivity analyses were performed on the solid loading rate, temperature, acid concentration and water evaporation rate. The results from the sensitivity analyses established that the solids loading rate had the most significant impact on the energy demand. The model was then verified with data from the NREL benchmark process. Application of this model on other dilute acid pretreatment processes reported in the literature illustrated that although similar sugar yields were reported by several studies, the energy required by the different pretreatments varied significantly.
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Affiliation(s)
- Oluwakemi A.T. Mafe
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, United Kingdom
| | - Scott M. Davies
- Briggs of Burton, Briggs House, Derby Street, Burton on Trent, Staffordshire DE14 2LH, United Kingdom
| | - John Hancock
- Briggs of Burton, Briggs House, Derby Street, Burton on Trent, Staffordshire DE14 2LH, United Kingdom
| | - Chenyu Du
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, United Kingdom
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Normark M, Winestrand S, Lestander TA, Jönsson LJ. Analysis, pretreatment and enzymatic saccharification of different fractions of Scots pine. BMC Biotechnol 2014; 14:20. [PMID: 24641769 PMCID: PMC3984014 DOI: 10.1186/1472-6750-14-20] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/12/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Forestry residues consisting of softwood are a major lignocellulosic resource for production of liquid biofuels. Scots pine, a commercially important forest tree, was fractionated into seven fractions of chips: juvenile heartwood, mature heartwood, juvenile sapwood, mature sapwood, bark, top parts, and knotwood. The different fractions were characterized analytically with regard to chemical composition and susceptibility to dilute-acid pretreatment and enzymatic saccharification. RESULTS All fractions were characterized by a high glucan content (38-43%) and a high content of other carbohydrates (11-14% mannan, 2-4% galactan) that generate easily convertible hexose sugars, and by a low content of inorganic material (0.2-0.9% ash). The lignin content was relatively uniform (27-32%) and the syringyl-guaiacyl ratio of the different fractions were within the range 0.021-0.025. The knotwood had a high content of extractives (9%) compared to the other fractions. The effects of pretreatment and enzymatic saccharification were relatively similar, but without pretreatment the bark fraction was considerably more susceptible to enzymatic saccharification. CONCLUSIONS Since sawn timber is a main product from softwood species such as Scots pine, it is an important issue whether different parts of the tree are equally suitable for bioconversion processes. The investigation shows that bioconversion of Scots pine is facilitated by that most of the different fractions exhibit relatively similar properties with regard to chemical composition and susceptibility to techniques used for bioconversion of woody biomass.
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Affiliation(s)
| | | | | | - Leif J Jönsson
- Department of Chemistry, Umeå University, Umeå SE-901 87, Sweden.
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Chen HZ, Liu ZH. Multilevel composition fractionation process for high-value utilization of wheat straw cellulose. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:137. [PMID: 25426164 PMCID: PMC4240850 DOI: 10.1186/s13068-014-0137-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 09/03/2014] [Indexed: 05/11/2023]
Abstract
BACKGROUND Biomass refining into multiple products has gained considerable momentum due to its potential benefits for economic and environmental sustainability. However, the recalcitrance of biomass is a major challenge in bio-based product production. Multilevel composition fractionation processes should be beneficial in overcoming biomass recalcitrance and achieving effective conversion of multiple compositions of biomass. The present study concerns the fractionation of wheat straw using steam explosion, coupled with ethanol extraction, and that this facilitates the establishment of sugars and lignin platform and enables the production of regenerated cellulose films. RESULTS The results showed that the hemicellulose fractionation yield was 73% under steam explosion at 1.6 MPa for 5.2 minutes, while the lignin fractionation yield was 90% by ethanol extraction at 160°C for 2 hours and with 60% ethanol (v/v). The cellulose yield reached up to 93% after steam explosion coupled with ethanol extraction. Therefore, cellulose sugar, hemicellulose sugar, and lignin platform were established effectively in the present study. Long fibers (retained by a 40-mesh screening) accounted for 90% of the total cellulose fibers, and the glucan conversion of short fibers was 90% at 9.0 hours with a cellulase loading of 25 filter paper units/g cellulose in enzymatic hydrolysis. Regenerated cellulose film was prepared from long fibers using [bmim]Cl, and the tensile strength and breaking elongation was 120 MPa and 4.8%, respectively. The cross-section of regenerated cellulose film prepared by [bmim]Cl displayed homogeneous structure, which indicated a dense architecture and a better mechanical performance. CONCLUSIONS Multilevel composition fractionation process using steam explosion followed by ethanol extraction was shown to be an effective process by which wheat straw could be fractionated into different polymeric fractions with high yields. High-value utilization of wheat straw cellulose was achieved by preparing regenerated cellulose film using [bmim]Cl.
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Affiliation(s)
- Hong-Zhang Chen
- />State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, No.1 Zhongguancun North Second Street, Haidian District Beijing, 100190 PR China
| | - Zhi-Hua Liu
- />State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, No.1 Zhongguancun North Second Street, Haidian District Beijing, 100190 PR China
- />University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District Beijing, 100049 PR China
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