Plant cell wall composition and enzymatic deconstruction

Thatiane Rodrigues Mota; Dyoni Matias de Oliveira; Rogério Marchiosi; Osvaldo Ferrarese-Filho; Wanderley Dantas dos Santos; Thatiane Rodrigues Mota; Dyoni Matias de Oliveira; Rogério Marchiosi; Osvaldo Ferrarese-Filho; Wanderley Dantas dos Santos

doi:10.3934/bioeng.2018.1.63

AIMS Bioengineering

2018, Volume 5, Issue 1: 63-77. doi: 10.3934/bioeng.2018.1.63

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Review Topical Sections

Plant cell wall composition and enzymatic deconstruction

Laboratory of Plant Biochemistry, Department of Biochemistry, State University of Maringá, PR, Brazil

Received: 20 December 2017 Accepted: 14 March 2018 Published: 30 March 2018

Cellulosic ethanol is one the most prominent technologies capable of replacing the use of fossil fuels in an observable horizon of technological development. The complexity of plant biomass, however, continues to challenge our ability to convert it into biofuels efficiently. Highly complex and cross-linked polysaccharides, hydrophobic and protein adsorbent polymers, and crystalline supramolecular structures comprise some of the structures that shield the plant cell contents (and the shield structures themselves) against predators. In response, a sophisticated enzymatic weaponry, with its associated chemical and physical mechanisms, is necessary to overcome this recalcitrance. Here we describe basic information about chemical composition of lignocellulosic biomass and the enzymatic arsenal for lignocellulose deconstruction into fermentable sugars.
- biomass,
- cellulose,
- enzymatic hydrolysis,
- hemicellulose,
- lignin,
- lignocellulose,
- saccharification
Citation: Thatiane Rodrigues Mota, Dyoni Matias de Oliveira, Rogério Marchiosi, Osvaldo Ferrarese-Filho, Wanderley Dantas dos Santos. Plant cell wall composition and enzymatic deconstruction[J]. AIMS Bioengineering, 2018, 5(1): 63-77. doi: 10.3934/bioeng.2018.1.63

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Abstract

Cellulosic ethanol is one the most prominent technologies capable of replacing the use of fossil fuels in an observable horizon of technological development. The complexity of plant biomass, however, continues to challenge our ability to convert it into biofuels efficiently. Highly complex and cross-linked polysaccharides, hydrophobic and protein adsorbent polymers, and crystalline supramolecular structures comprise some of the structures that shield the plant cell contents (and the shield structures themselves) against predators. In response, a sophisticated enzymatic weaponry, with its associated chemical and physical mechanisms, is necessary to overcome this recalcitrance. Here we describe basic information about chemical composition of lignocellulosic biomass and the enzymatic arsenal for lignocellulose deconstruction into fermentable sugars.

References

[1]	Santos WDD, Gómez ED, Buckeridge MS, (2011) Bioenergy and the Sustainable Revolution, In: Buckeridge MS, Goldman GH. Routes to Cellulosic Ethanol. Springer Science and Business Media, LCC, 1 Ed., New York, 15–26.
[2]	Jaiswal D, Souza APD, Larsen S, et al. (2017) Brazilian sugarcane ethanol as an expandable green alternative to crude oil use. Nat Clim Change 7: 788–792. doi: 10.1038/nclimate3410
[3]	Saini JK, Saini R, Tewari L (2015) Lignocellulosic agriculture wastes as biomass feedstocks for second-generation bioethanol production: Concepts and recent developments. Biotech 5: 337–353.
[4]	Buckeridge MS, Dos Santos WD, Mas T, et al. (2016) The cell wall architecture of sugarcane and its implications to cell wall recalcitrance, In: Lam E, Carrer H, Da Silva JA, et al. Compendium of Bioenergy Plants: Compendium of Bioenergy Plants, Boca Raton, FL: CRC Press, 31–50.
[5]	Poovaiah CR, Nageswara-Rao M, Soneji JR, et al. (2014) Altered lignin biosynthesis using biotechnology to improve lignocellulosic biofuel feedstocks. Plant Biotechnol J 12: 1163–1173. doi: 10.1111/pbi.12225
[6]	Torres AF, Visser RGF, Trindade LM (2015) Bioethanol from maize cell walls: Genes, molecular tools, and breeding prospects. GCB Bioenergy 7: 591–607. doi: 10.1111/gcbb.12164
[7]	Balat M (2011) Production of bioethanol from lignocellulosic materials via the biochemical pathway: A review. Energ Convers Manage 52: 858–875. doi: 10.1016/j.enconman.2010.08.013
[8]	Souza APD, Leite DCC, Pattathil S, et al. (2013) Composition and structure of sugarcane cell wall polysaccharides: Implications for second-generation bioethanol production. BioEnergy Res 6: 564–579. doi: 10.1007/s12155-012-9268-1
[9]	Gupta A, Verma JP (2015) Sustainable bio-ethanol production from agro-residues. Renew Sust Energ Rev 41: 550–567. doi: 10.1016/j.rser.2014.08.032
[10]	Sims REH, Mabee W, Saddler JN, et al. (2010) An overview of second generation biofuel technologies. Bioresource Technol 101: 1570–1580. doi: 10.1016/j.biortech.2009.11.046
[11]	Amorim HV, Lopes ML, Oliveira JVC, et al. (2011) Scientific challenges of bioethanol production in Brazil. Appl Microbiol Biotechnol 91: 1267–1275. doi: 10.1007/s00253-011-3437-6
[12]	Verardi A, Blasi A, Molino A, et al. (2016) Improving the enzymatic hydrolysis of Saccharum officinarum L. bagasse by optimizing mixing in a stirred tank reactor: Quantitative analysis of biomass conversion. Fuel Process Technol 149: 15–22.
[13]	Limayem A, Ricke SC (2012) Lignocellulosic biomass for bioethanol production: Current perspectives, potential issues and future prospects. Prog Energy Combust Sci 38: 449–467. doi: 10.1016/j.pecs.2012.03.002
[14]	Goldemberg J, Coelho ST, Guardabassi P (2008) The sustainability of ethanol production from sugarcane. Energ Policy 36: 2086–2097. doi: 10.1016/j.enpol.2008.02.028
[15]	Rocha GJM, Gonçalves AR, Oliveira BR, et al. (2013) Steam explosion pretreatment reproduction and alkaline deligniﬁcation reactions performed on a pilot scale with sugarcane bagasse for bioethanol production. Ind Crop Prod 35: 274–279.
[16]	Buckeridge MS, Santos WDD, Souza AP, (2010) Routes for cellulosic ethanol in Brazil, In: Cortez LAB. Sugarcane Bioethanol, R&D for productivity and sustainability, Blucher, 992.
[17]	Kou L, Song Y, Zhang X, et al. (2017) Comparison of four types of energy grasses as lignocellulosic feedstock for the production of bio-ethanol. Bioresource Technol 241:434–429.
[18]	Álvarez C, Manuel RF, Bruno D (2016) Enzymatic hydrolysis of biomass from wood. Microb Biotechnol 9: 149–156. doi: 10.1111/1751-7915.12346
[19]	Malinovsky FG, Fangel JU, Willats WGT (2014) The role of the cell wall in plant immunity. Front Plant Sci 5: 178.
[20]	Payne CM, Knott BC, Mayes HB, et al. (2015) Fungal cellulases. Chem Rev 115: 1308–1448. doi: 10.1021/cr500351c
[21]	Khare SK, Pandey A, Larroche C (2015) Current perspectives in enzymatic saccharification of lignocellulosic biomass. Biochem Eng J 102: 38–44. doi: 10.1016/j.bej.2015.02.033
[22]	Jørgensen H, Kristensen JB, Felby C (2007) Enzymatic conversion of lignocellulose into fermentable sugars: Challenges and opportunities. Biofuels Bioprod Biorefin 1: 119–134.
[23]	Le GH, Florian F, Jean-Marc D, et al. (2015) Cell wall metabolism in response to abiotic stress. Plants 4: 112–166. doi: 10.3390/plants4010112
[24]	Pauly M, Keegstra K (2008) Cell-wall carbohydrates and their modiﬁcation as are source for biofuels. Plant J 54: 559–568. doi: 10.1111/j.1365-313X.2008.03463.x
[25]	Höfte H, Voxeur A (2017) Plant cell walls. Curr Biol 27: R865–R870. doi: 10.1016/j.cub.2017.05.025
[26]	Carpita NC, Gibeaut DM (1993) Structural models of primary cell walls in flowering plants: Consistency of molecular structure with the physical properties of the walls during growth. Plant J 3: 1–30. doi: 10.1111/j.1365-313X.1993.tb00007.x
[27]	Chundawat SPS, Beckham GT, Himmel ME, et al. (2011) Deconstruction of lignocellulosic biomass to fuels and chemicals. Annu Rev Chem Biomol Eng 2: 121–145. doi: 10.1146/annurev-chembioeng-061010-114205
[28]	Meents MJ, Watanabe Y, Samuels AL (2018) The cell biology of secondary cell wall biosynthesis. Ann Bot.
[29]	Turner S, Kumar M (2018) Cellulose synthase complex organization and cellulose microfibril structure. Philos Trans 376: 20170048.
[30]	Himmel ME, Ding SY, Johnson DK, et al. (2007) Biomass recalcitrance: Engineering plants and enzymes for biofuels production. Science 315: 804–807. doi: 10.1126/science.1137016
[31]	Carpita NC, Mccann MC, (2000) The cell wall, In: Buchanan BB, Gruissem W, Jones RL, Biochemistry and molecular biology of plants. Rockville: IL: American Society of Plant Physiologists, 1367.
[32]	Abramson M, Shoseyov O, Shani Z (2010) Plant cell wall reconstruction toward improved lignocellulosic production and processability. Plant Sci 178: 61–72. doi: 10.1016/j.plantsci.2009.11.003
[33]	Van dWT, Dolstra O, Visser RG, et al. (2017) Stability of cell wall composition and saccharification efficiency in miscanthus across diverse environments. Front Plant Sci 7: 2004.
[34]	Pauly M, Keegstra K (2016) Biosynthesis of the plant cell wall matrix polysaccharide xyloglucan. Annu Rev Plant Biol 67: 235–259. doi: 10.1146/annurev-arplant-043015-112222
[35]	Oliveira DM, Finger-Teixeira A, Mota TR, et al. (2016). Ferulic acid: A key component in grass lignocellulose recalcitrance to hydrolysis. Plant Biotechnol J 13: 1224–1232.
[36]	Kozlova LV, Ageeva MV, Ibragimova NN, et al. (2014) Arrangement of mixed-linkage glucan and glucuronoarabinoxylan in the cell walls of growing maize roots. Ann Bot 114: 1135–1145. doi: 10.1093/aob/mcu125
[37]	Srivastava PK, Kapoor M (2017) Production, properties, and applications of endo-β-mannanases. Biotechnol Adv 35: 1–19. doi: 10.1016/j.biotechadv.2016.11.001
[38]	Biswal AK, Atmodjo MA, Li M, et al. (2018) Sugar release and growth of biofuel crops are improved by downregulation of pectin biosynthesis. Nat Biotechnol.
[39]	Voragen AGJ, Coenen GJ, Verhoef RP, et al. (2009) Pectin, a versatile polysaccharide present in plant cell walls. Struct Chem 20: 263–275. doi: 10.1007/s11224-009-9442-z
[40]	Mohnen D (2008) Pectin structure and biosynthesis. Curr Opin Plant Biol 11: 266–277. doi: 10.1016/j.pbi.2008.03.006
[41]	Nguyen TN, Son S, Jordan MC, et al. (2016) Lignin biosynthesis in wheat (Triticum aestivum L.): Its response to waterlogging and association with hormonal levels. BMC Plant Biol 16: 1–16.
[42]	Ragauskas AJ, Beckham GT, Biddy MJ, et al. (2014) Lignin valorization: Improving lignin processing in the biorefinery. Science 344: 1246843. doi: 10.1126/science.1246843
[43]	Santos WDD, Ferrarese MDLL (2008) Ferulic acid: An allelochemical troublemaker. Funct Plant Sci Biotechnol 2: 47–55.
[44]	dos Santos WD, Ferrarese ML, Nakamura CV, et al. (2008) Soybean (Glycine max) root lignification induced by ferulic acid the possible mode of action. J Chem Ecol 34: 1230–1241. doi: 10.1007/s10886-008-9522-3
[45]	Liu Q, Luo L, Zheng L (2018) Lignins: Biosynthesis and Biological Functions in Plants. Int J Mol Sci 19: 335.
[46]	Salvador VH, Lima RB, dos Santos WD, et al. (2013) Cinnamic acid increases lignin production and inhibits soybean root growth. PLoS One 8: e69105. doi: 10.1371/journal.pone.0069105
[47]	Oliveira DMD, Finger-Teixeira A, Freitas DLD, et al. (2017) Phenolic Compounds in Plants: Implications for Bioenergy, In: Buckeridge MS, de Souza AP, Advances of Basic Science for Second Generation Bioethanol from Sugarcane, Springer Int Publishing, 39–52.
[48]	Boerjan W, Ralph J, Baucher M (2003) Lignin biosynthesis. Annu Rev Plant Biol 166: 63–71.
[49]	Moreira-Vilar FC, Siqueira-Soares RC, Finger-Teixeira A, et al. (2014) The acetyl bromide method is faster, simpler and presents best recovery of lignin in different herbaceous tissues than klason and thioglycolic acid methods. PLoS One 9: e110000. doi: 10.1371/journal.pone.0110000
[50]	Santos WDD, Marchiosi R, Vilar FCW, et al. (2014) Polyvalent Lignin: Recent Approaches in Determination and Applications, In: Lu F, Lignin: Structural analysis, applications in biomaterials and ecological significance, New York: Nova Publishers, 1–26.
[51]	Fornalé S, Rencoret J, Garcíacalvo L, et al. (2017) Changes in cell wall polymers and degradability in maize mutants lacking 3′- and 5′-O-methyltransferases involved in lignin biosynthesis. Plant Cell Physiol 58: 240–255.
[52]	Lima RB, Salvador VH, dos Santos WD, et al. (2013) Enhanced lignin monomer production caused by cinnamic acid and its hydroxylated derivatives inhibits soybean root growth. PLoS One 8: e80542. doi: 10.1371/journal.pone.0080542
[53]	Saritha M, Arora A, Lata (2012) Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility. Indian J Microbiol 52: 122–130. doi: 10.1007/s12088-011-0199-x
[54]	Henrissat B, Bairoch A (1993) New families in the classification of glycosyl hydrolases based on amino acid sequence similarities. Biochem J 293: 781–788. doi: 10.1042/bj2930781
[55]	Lombard V, Ramulu HG, Drula E, et al. (2014) The carbohydrate-active enzymes database (CAZy). Nucleic Acids Res 42: D490–D495. doi: 10.1093/nar/gkt1178
[56]	Bourne Y, Henrissat B (2001) Glycoside hydrolases and glycosyltransferases families and functional modules. Curr Opin Struc Biol 11: 593–600. doi: 10.1016/S0959-440X(00)00253-0
[57]	Hashimoto H (2006) Recent structural studies of carbohydrate-binding modules. Cell Mol Life Sci 63: 2954–2967. doi: 10.1007/s00018-006-6195-3
[58]	Boraston AB, Bolam DN, Gilbert HJ, et al. (2004) Carbohydrate-binding modules: Fine-tuning polysaccharide recognition. Biochem J 382: 769–781. doi: 10.1042/BJ20040892
[59]	Davies G, Henrissat B (1995) Structures and mechanisms of glycosyl hydrolases. Structure 3: 853–859. doi: 10.1016/S0969-2126(01)00220-9
[60]	Terrapon N, Lombard V, Drula E, et al. (2017) The CAZy Database/the Carbohydrate-Active Enzyme (CAZy) Database: Principles and Usage Guidelines, In: Aoki-Kinoshita K (eds), A Practical Guide to Using Glycomics Databases. Springer, Tokyo, 117–131.
[61]	Segato F, Dias B, Berto GL, et al. (2017) Cloning, heterologous expression and biochemical characterization of a non-specific endoglucanase family 12 from Aspergillus terreus NIH2624. BBA 1865: 395–403.
[62]	Segato F, Damásio AR, de Lucas RC, et al. (2014) Genomics review of holocellulose deconstruction by aspergilli. Microbiol Mol Biol Rev 78: 588–613. doi: 10.1128/MMBR.00019-14
[63]	Olsen JP, Alasepp K, Kari J, et al. (2016) Mechanism of product inhibition for cellobiohydrolase Cel7A during hydrolysis of insoluble cellulose. Biotechnol Bioeng 113: 1178–1186.
[64]	Grange DC, Haan R, Zyl WH (2010) Engineering cellulolytic ability into bioprocessing organisms. Appl Microbiol Biotechnol 87: 1195–1208. doi: 10.1007/s00253-010-2660-x
[65]	Damásio ARL, Rubio MV, Gonçalves TA, et al. (2017) Xyloglucan breakdown by endo-xyloglucanase family 74 from Aspergillus fumigatus. Appl Microbiol Biotechnol 101: 2893–2903. doi: 10.1007/s00253-016-8014-6
[66]	Dodd D, Cann IKO (2009) Enzymatic deconstruction of xylan for biofuel production. GCB Bioenergy 1: 2–17. doi: 10.1111/j.1757-1707.2009.01004.x
[67]	Damásio ARDL, Pessedela BC, Segato F, et al. (2012) Improvement of fungal arabinofuranosidase thermal stability by reversible immobilization. Process Biochem 47: 2411–2417. doi: 10.1016/j.procbio.2012.09.024
[68]	Wilkens C, Andersen S, Dumon C, et al. (2017) GH62 arabinofuranosidases: Structure, function and applications. Biotechnol Adv 35: 792–804. doi: 10.1016/j.biotechadv.2017.06.005
[69]	Wu L, Jiang J, Kallemeijn W, et al. (2017) Activity-based probes for functional interrogation of retaining β-glucuronidases. Nat Chem Biol 13: 867–873 doi: 10.1038/nchembio.2395
[70]	Bornscheuer UT (2002) Microbial carboxyl esterases: Classification, properties and application in biocatalysis. FEMS Microbiol Rev 26: 73–81. doi: 10.1111/j.1574-6976.2002.tb00599.x
[71]	Krastanova I, Guarnaccia C, Zahariev S, et al. (2005) Heterologous expression, purification, crystallization, X-ray analysis and phasing of the acetyl xylan esterase from Bacillus pumilus. BBA 1748: 222–230.
[72]	Wong DWS (2006) Feruloyl esterase, a key enzyme in biomass degradation. Appl Biochem Biotechnol 133: 87–111. doi: 10.1385/ABAB:133:2:87
[73]	Dilokpimol A, Mäkelä MR, Aguilarpontes MV, et al. (2016) Diversity of fungal feruloyl esterases: Updated phylogenetic classification, properties, and industrial applications. Biotechnol Biofuels 9: 231. doi: 10.1186/s13068-016-0651-6
[74]	Faulds CB, Mandalari G, Curto RBL, et al. (2006) Synergy between xylanases from glycoside hydrolase family 10 and 11 and a feruloyl esterase in the release of phenolic acids from cereal arabinoxylan. Appl Microbiol Biotechnol 71: 622–629. doi: 10.1007/s00253-005-0184-6
[75]	Wong DWS, Chan VJ, Liao H, et al. (2013) Cloning of a novel feruloyl esterase gene from rumen microbial metagenome and enzyme characterization in synergism with endoxylanases. J Ind Microbiol Biotechnol 40: 287–295.
[76]	Pérezrodríguez N, Moreira CD, Torrado AA, et al. (2016) Feruloyl esterase production by Aspergillus terreus CECT 2808 and subsequent application to enzymatic hydrolysis. Enzyme Microb Tech 91: 52–58. doi: 10.1016/j.enzmictec.2016.05.011
[77]	Oliveira DM, Salvador VH, Mota TR, et al. (2016) Feruloyl esterase from Aspergillus clavatus improves xylan hydrolysis of sugarcane bagasse. AIMS Bioeng 4: 1–11. doi: 10.3934/bioeng.2017.1.1
[78]	Garg G, Singh A, Kaur A, et al. (2016) Microbial pectinases: An ecofriendly tool of nature for industries. Biotech 6: 47.
[79]	Kant S, Vohra A, Gupta R (2013) Purification and physicochemical properties of polygalacturonase from Aspergillus niger MTCC 3323. Protein Expres Purif 87: 11–16.
[80]	Chen Q, Jin Y, Zhang G, et al. (2012) Improving production of bioethanol from duckweed (Landoltia punctata) by pectinase pretreatment. Energies 5: 3019–3032. doi: 10.3390/en5083019
[81]	Kataria R, Ghosh S (2011) Saccharification of Kans grass using enzyme mixture from Trichoderma reesei for bioethanol production. Bioresource Technol 102: 9970–9975. doi: 10.1016/j.biortech.2011.08.023
[82]	Oberoi HS, Vadlani PV, Nanjundaswamy A, et al. (2011) Enhanced ethanol production from Kinnow mandarin (Citrus reticulata) waste via a statistically optimized simultaneous saccharification and fermentation process. Bioresource Technol 102: 1593–1601.
[83]	Shanmugam VK, Gopalakrishnan D (2016) Screening and partial purification for the production of ligninase enzyme from the fungal isolate Trichosporon asahii. Braz Arch Biol Technol 59: e160220.
[84]	Vrsanska M, Voberkova S, Langer V, et al. (2016) Induction of laccase, lignin peroxidase and manganese peroxidase activities in white-rot fungi using copper complexes. Molecules 21: E1553. doi: 10.3390/molecules21111553
[85]	Pan L, Zhao H, Yu Q (2017) miR397/Laccase gene mediated network improves tolerance to fenoxaprop-P-ethyl in Beckmannia syzigachne and Oryza sativa. Front Plant Sci 23: 879.
[86]	Kameshwar AKS, Qin W (2016) Recent developments in using advanced sequencing technologies for the genomic studies of lignin and cellulose degrading microorganisms. Int J Biol Sci 12: 156–171. doi: 10.7150/ijbs.13537
[87]	Rastogi M, Shrivastava S (2017) Recent advances in second generation bioethanol production: An insight to pretreatment, saccharification and fermentation processes. Renew Sust Energ Rev 80: 330–340. doi: 10.1016/j.rser.2017.05.225
[88]	Huang R, Su R, Qi W, et al. (2011) Bioconversion of lignocellulose into bioethanol process intensification and mechanism research. BioEnerg Res 4: 225–245. doi: 10.1007/s12155-011-9125-7
[89]	Lygin AV, Upton J, Dohleman FG, et al. (2011) Composition of cell wall phenolics and polysaccharides of the potential bioenergy crop-Miscanthus. Global Change Biol Bioenergy 3: 333–345. doi: 10.1111/j.1757-1707.2011.01091.x
[90]	Wei Y, Li X, Yu L, et al. (2015) Mesophilic anaerobic co-digestion of cattle manure and corn stover with biological and chemical pretreatment. Bioresource Technol 198: 431–436. doi: 10.1016/j.biortech.2015.09.035
[91]	Balat M, Balat H (2009) Recent trends in global production and utilization of bio-ethanol fuel. Appl Energ 86: 2273–2282. doi: 10.1016/j.apenergy.2009.03.015
[92]	Cianchetta S, Maggio BD, Burzi PL, et al. (2014) Evaluation of selected white-rot fungal isolates for improving the sugar yield from wheat straw. Appl Biochem Biotechnol 173: 609–623.
[93]	Behera S, Arora R, Nandhagopal N, et al. (2014) Importance of chemical pretreatment for bioconversion of lignocellulosic biomass. Renew Sust Energ Rev 36: 91–106. doi: 10.1016/j.rser.2014.04.047
[94]	Safari A, Karimi K, Shafiei M (2017) Dilute alkali pretreatment of softwood pine: A biorefinery approach. Bioresource Technol 234: 67–76. doi: 10.1016/j.biortech.2017.03.030
[95]	Rabemanolontsoa H, Saka S (2016) Various pretreatments of lignocellulosics. Bioresource Technol 199: 83–91. doi: 10.1016/j.biortech.2015.08.029
[96]	Zhu Z, Simister R, Bird S, et al. (2015) Microwave assisted acid and alkali pretreatment of Miscanthus biomass for biorefineries. AIMS Bioeng 2: 446–468.
[97]	Tang C, Shan J, Chen Y, et al. (2017) Organic amine catalytic organosolv pretreatment of corn stover for enzymatic saccharification and high-quality lignin. Bioresource Technol 232: 222–228. doi: 10.1016/j.biortech.2017.02.041
[98]	Silva ASD, Inoue H, Endo T, et al. (2010) Milling pretreatment of sugarcane bagasse and straw for enzymatic hydrolysis and ethanol fermentation. Bioresource Technol 101: 7402–7409. doi: 10.1016/j.biortech.2010.05.008
[99]	Chemat S, Lagha A, AitAmar H, et al. (2004) Comparison of conventional and ultrasound-assisted extraction of carvone and limonene from caraway seeds. Flavour Frag J 19: 188–195. doi: 10.1002/ffj.1339
[100]	Sipponen MH, Rahikainen J, Leskinen T, et al. (2017) Structural changes of lignin in biorefinery pretreatments. Nord Pulp Pap Res J 32: 547–568.
[101]	Fang H, Zhao C, Song XY, et al. (2013) Enhanced cellulolytic enzyme production by the synergism between Trichoderma reesei RUT-30 and Aspergillus niger NL02 and by the addition of surfactants. Biotechnol Bioprocess Eng 18: 390–398. doi: 10.1007/s12257-012-0562-8

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