Thermomechanical biorefining of Pinus radiata biomass to produce biochemicals using reactive extrusion

Abstract

Currently, ca. 30 million m³ of Pinus radiata are harvested annually in New Zealand to produce timber, pulp and paper, with by-products such as bark and sawdust generated during processing. The most common use for sawdust is as a solid fuel for process heat. However, it is a feedstock that can be processed into platform biochemicals. Although conversion processes focusing on biochemical production from wood are scarce, they are becoming more commercially established. Here, reactive extrusion was explored as a continuous, fast method to depolymerise sawdust into soluble biochemicals with residence times of less than two minutes. This is substantially shorter than other biotechnology routes or conventional batch processing and highlights the potential for integration of reactive extrusion into biorefinery operations. While conventional wood extrusion focused on the solid fraction, this work extensively investigated the liquid biochemical profile. The effects of temperature, moisture content, screw speed, and screw design on the biochemical yield from sawdust were studied. The results indicated that kneading elements in the screw design were key to achieving good processing of the sawdust. A high moisture content of 50% (by weight) was instrumental in the isolation of biochemicals. Moreover, the screw speed had little to no effect on the biochemical composition obtained from the reactive extrusion process. Finally, a maximum of 6.5–7.5% of biochemicals were recovered from sawdust in the liquid phase when processed between 325 °C and 375 °C. The biochemical analyses of the liquor showed a high amount of acetic acid (up to 7913 mg/L) and methanol (up to 2277 mg/L). Furthermore, the furanic content increased with an increase in temperature between 275 °C and 375 °C, while an inverse trend was observed for aromatic phenols. The analyses also revealed that lignin and hemicellulose were depolymerised to produce oligomeric and monomeric breakdown products, while cellulose was untouched. This study successfully demonstrated the successful use of a twin-screw reactive extruder to continuously produce a biochemical-rich liquor from sawdust.

Keywords

Reactive extrusion / Biochemicals / Biorefinery / Green manufacturing / Lignocellulosic biomass

References

[1] Allais F. Total syntheses and production pathways of levoglucosenone, a highly valuable chiral chemical platform for the chemical industry. Curr Opin Green Sustain Chem, 2023, 40 100744

[2] ASTM (2017) Standard test method for determination of moisture in plastics by loss in weight. In ASTM D6890–17.

[3] ASTM (2020) Standard test method for direct moisture content measurement of wood and wood-based materials. In ASTM D4442–20.

[4] Baccile N, Falco C, Titirici M-M. Characterization of biomass and its derived char using 13C-solid state nuclear magnetic resonance. Green Chem, 2014, 16(12): 4839-4869

[5] Barakat A, Mayer-Laigle C, Solhy A, Arancon RAD, de Vries H, Luque R. Mechanical pretreatments of lignocellulosic biomass: towards facile and environmentally sound technologies for biofuels production. RSC Adv, 2014, 4(89): 48109-48127

[6] BCC-Research. (2024). Biorefinery Products and Applications: Global Markets. BCC-Publishing. https://www.bccresearch.com/market-research/energy-and-resources/biorefinery-products-markets-report.html

[7] Berntsson T, Sandén BA, Olsson L, Åsblad A (2012) What is a biorefinery?

[8] Borrega M, Nieminen K, Sixta H. Degradation kinetics of the main carbohydrates in birch wood during hot water extraction in a batch reactor at elevated temperatures. Bioresour Technol, 2011, 102(22): 10724-10732

[9] Braghiroli FL, Passarini L. Valorization of biomass residues from forest operations and wood manufacturing presents a wide range of sustainable and innovative possibilities. Curr Forestry Rep, 2020, 6(2): 172-183

[10] Calcio Gaudino E, Grillo G, Manzoli M, Tabasso S, Maccagnan S, Cravotto G. Mechanochemical applications of reactive extrusion from organic synthesis to catalytic and active materials. Molecules, 2022

[11] Casau M, Dias MF, Matias JCO, Nunes LJR. Residual biomass: a comprehensive review on the importance, uses and potential in a circular bioeconomy approach. Resources, 2022

[12] Collard F-X, Blin J. A review on pyrolysis of biomass constituents: mechanisms and composition of the products obtained from the conversion of cellulose, hemicelluloses and lignin. Renew Sustain Energy Rev, 2014, 38: 594-608

[13] Cooke-Willis M, Davy B, Theobald B, Robertson M, Gaugler M, Hall P, Song B. Heterodox torrefaction of the forest residue with a twin-screw extrusion reactor. Energy Fuels, 2024, 38(16): 15375-15384

[14] Duque A, Manzanares P, Ballesteros M. Extrusion as a pretreatment for lignocellulosic biomass: fundamentals and applications. Renewable Energy, 2017, 114: 1427-1441

[15] Elhassan M, Kooh MRR, Chou Chau Y-F, Abdullah R. Techno-economic and life cycle analysis of hydrothermal liquefaction: a case study on Shorea sawdust. Biomass Convers Biorefin, 2025, 15(11): 17591-17614

[16] Eseyin AE, Steele PH. An overview of the applications of furfural and its derivatives. Int J Adv Chem, 2015

[17] Foston M. Advances in solid-state NMR of cellulose. Curr Opin Biotechnol, 2014, 27: 176-184

[18] Giummarella N, Lawoko M. Structural insights on recalcitrance during hydrothermal hemicellulose extraction from wood. ACS Sustain Chem Eng, 2017, 5(6): 5156-5165

[19] Godavarti S, Karwe MV. Determination of specific mechanical energy distribution on a twin-screw extruder. J Agric Eng Res, 1997, 67(4): 277-287

[20] Gu B-J, Dhumal GS, Wolcott MP, Ganjyal GM. Disruption of lignocellulosic biomass along the length of the screws with different screw elements in a twin-screw extruder. Bioresour Technol, 2019, 275: 266-271

[21] Guiao KS, Gupta A, Tzoganakis C, Mekonnen TH. Reactive extrusion as a sustainable alternative for the processing and valorization of biomass components. J Clean Prod, 2022, 355 131840

[22] He Y, Zhang S, Liu D, Xie X, Li B. Effect of biomass particle size on the torrefaction characteristics in a fixed-bed reactor. Energies, 2023

[23] Hietala M, Niinimäki J, Oksman K. The use of twin-screw extrusion in processing of wood: the effect of processing parameters and pretreatment [Article]. BioResources, 2011, 6(4): 4615-4625

[24] Hill SJ, Grigsby WJ, Hall PW. Chemical and cellulose crystallite changes in Pinus radiata during torrefaction. Biomass Bioenerg, 2013, 56: 92-98

[25] Hiltunen E, Pakkanen TT, Alvila L. Phenolic compounds in silver birch (Betula pendula Roth) wood. Holzforschung, 2006, 60(5): 519-527

[26] Hopmann C, Adamy M, Cohnen A (2017) Introduction to reactive extrusion. In reactive extrusion pp. 1–10. https://doi.org/10.1002/9783527801541.ch1

[27] IEA-Bioenergy. (2022b). IEA bioenergy task 42, global biorefinery status report (Global biorefinery status report, Issue. https://www.ieabioenergy.com/blog/publications/global-biorefinery-status-report/

[28] Jiang B, Jiao H, Guo X, Chen G, Guo J, Wu W, Jin Y, Cao G, Liang Z. Lignin-based materials for additive manufacturing: chemistry, processing, structures, properties, and applications. Adv Sci, 2023, 10(9): 2206055

[29] Joshi M, Manjare S. Chemical approaches for the biomass valorisation: a comprehensive review of pretreatment strategies. Environ Sci Pollut Res Int, 2024, 31(3648928-48954

[30] Karimipour-Fard P, Chio C, Brunone A, Marway H, Thompson M, Abdehagh N, Qin W, Yang TC. Lignocellulosic biomass pretreatment: industrial oriented high-solid twin-screw extrusion method to improve biogas production from forestry biomass resources. Bioresour Technol, 2024, 393 130000

[31] Karunanithy C, Muthukumarappan K. Influence of extruder and feedstock variables on torque requirement during pretreatment of different types of biomass: a response surface analysis. Biosyst Eng, 2011, 109(1): 37-51

[32] Karunanithy C, Muthukumarappan K. Gu T. Thermo-mechanical pretreatment of feedstocks. Green biomass pretreatment for biofuels production, 2013, Berlin, Springer3165

[33] Kim H, Ralph J. Solution-state 2D NMR of ball-milled plant cell wall gels in DMSO-d6/pyridine-d5. Organic Biomol Chem, 2010, 8(3): 576-591

[34] Kläusli T. AVA biochem: commercialising renewable platform chemical 5-HMF. Green Process Synth, 2014, 3(3): 235-236

[35] Konan D, Koffi E, Ndao A, Peterson EC, Rodrigue D, Adjallé K. An overview of extrusion as a pretreatment method of lignocellulosic biomass. Energies, 2022

[36] Kostyniuk A, Likozar B. Catalytic wet torrefaction of biomass waste into bio-ethanol, levulinic acid, and high quality solid fuel. Chem Eng J, 2024, 485 149779

[37] Koyande AK, Show P-L, Guo R, Tang B, Ogino C, Chang J-S. Bio-processing of algal bio-refinery: a review on current advances and future perspectives. Bioengineered, 2019, 10(1): 574-592

[38] Lamb WF, Wiedmann T, Pongratz J, Andrew R, Crippa M, Olivier JGJ, Wiedenhofer D, Mattioli G, Khourdajie AA, House J, Pachauri S, Figueroa M, Saheb Y, Slade R, Hubacek K, Sun L, Ribeiro SK, Khennas S, de la Rue du Can Chapungu SL, Davis SJ, Bashmakov I, Dai H, Dhakal S, Tan X, Geng Y, Gu B, Minx J. A review of trends and drivers of greenhouse gas emissions by sector from 1990 to 2018. Environ Res Lett, 2021, 16(7 073005

[39] Lease J, Kawano T, Andou Y. Effect of cellulose materials on the mechanochemical-assisted reaction system with oleic acid. RSC Adv, 2023, 13(39): 27558-27567

[40] Lee S-H, Teramoto Y, Endo T. Enzymatic saccharification of woody biomass micro/nanofibrillated by continuous extrusion process i - effect of additives with cellulose affinity. Bioresour Technol, 2009, 100(1): 275-279

[41] Liao Y, Koelewijn S-F, Van den Bossche G, Van Aelst J, Van den Bosch S, Renders T, Navare K, Nicolaï T, Van Aelst K, Maesen M, Matsushima H, Thevelein JM, Van Acker K, Lagrain B, Verboekend D, Sels BF. A sustainable wood biorefinery for low–carbon footprint chemicals production. Science, 2020, 367(6484): 1385-1390

[42] Liitiä T, Maunu SL, Hortling B, Tamminen T, Pekkala O, Varhimo A. Cellulose crystallinity and ordering of hemicelluloses in pine and birch pulps as revealed by solid-state NMR spectroscopic methods. Cellulose, 2003, 10(4): 307-316

[43] Liu R, Chen Y, Cao J. Characterization and properties of organo-montmorillonite modified lignocellulosic fibers and their interaction mechanisms. RSC Adv, 2015, 5(94): 76708-76717

[44] Mascal M, Nikitin EB. Towards the efficient, total glycan utilization of biomass. Chemsuschem, 2009, 2(5): 423-426

[45] Mathew S, Zakaria ZA. Pyroligneous acid: the smoky acidic liquid from plant biomass. Appl Microbiol Biotechnol, 2015, 99(2): 611-622

[46] Melkior T, Jacob S, Gerbaud G, Hediger S, Le Pape L, Bonnefois L, Bardet M. NMR analysis of the transformation of wood constituents by torrefaction. Fuel, 2012, 92(1): 271-280

[47] Miguel P, Pablo R, Regis Teixeira M. Effect of partial pre-extraction of hemicelluloses on the properties of pinus radiata chemimechanical pulps. BioResources, 2015, 10(4): 7442-7454

[48] Moad G. Chemical modification of starch by reactive extrusion. Prog Polym Sci, 2011, 36(2): 218-237

[49] Muschin T, Yoshida T. Structural analysis of galactomannans by NMR spectroscopy. Carbohydr Polym, 2012, 87(3): 1893-1898

[50] Nair LG, Agrawal K, Verma P. Organosolv pretreatment: an in-depth purview of mechanics of the system. Bioresour Bioprocess, 2023, 10(1): 50

[51] Namhaed K, Kiatkittipong W, Triquet T, Cognet P. Dehydration of pentose to furfural catalyzed by formic acid – kinetics and application to real biomass hydrolysates. J Environ Chem Eng, 2024, 12(5 113431

[52] N'Diaye S, Rigal L, Larocque P, Vidal PF. Extraction of hemicelluloses from poplar, Populus tremuloides, using an extruder-type twin-screw reactor: a feasibility study. Bioresour Technol, 1996, 57(161-67

[53] Olatunde A, Mohammed A, Ibrahim MA, Tajuddeen N, Shuaibu MN. Vanillin: a food additive with multiple biological activities. Eur J Med Chem Reports, 2022, 5 100055

[54] Pang S. Advances in thermochemical conversion of woody biomass to energy, fuels and chemicals. Biotechnol Adv, 2019, 37(4): 589-597

[55] Patel R, Rajaraman TS, Rana PH, Ambegaonkar NJ, Patel S. A review on techno-economic analysis of lignocellulosic biorefinery producing biofuels and high-value products. Results Chem, 2025, 13 102052

[56] Petridis L, Smith JC. Molecular-level driving forces in lignocellulosic biomass deconstruction for bioenergy. Nat Rev Chem, 2018, 2(11): 382-389

[57] Pettersen RC. Wood sugar analysis by anion chromatography. J Wood Chem Technol, 1991, 11(4): 495-501

[58] Prasad BR, Padhi RK, Ghosh G. A review on key pretreatment approaches for lignocellulosic biomass to produce biofuel and value-added products. Int J Environ Sci Technol, 2023, 20(6): 6929-6944

[59] Ranganathan S, Poovaiah CR, Vaidya AA, Dale RA, Tanjay QL, Wijeyekoon SLJ. Biohydrogen production from hemicellulose rich softwood hydrolysate. Chem Eng J, 2025, 506 160031

[60] Research-and-Markets. (2024). Biorefinery market by technology (industrial biotechnology, physico-chemical, thermochemical), product (energy, material), type (first generation (corn, vegetable oils, sugarcane), second generation, third generation) and region - global forecast to 2029. https://www.researchandmarkets.com/report/bio-refinery

[61] Santos TM, Rigual V, Domínguez JC, Alonso MV, Oliet M, Rodriguez F. Fractionation of Pinus radiata by ethanol-based organosolv process. Biomass Convers Biorefin, 2024, 14(1): 451-464

[62] Sermyagina E, Mendoza Martinez C, Lahti J, Nikku M, Mänttäri M, Kallioinen-Mänttäri M, Vakkilainen E. Characterization of pellets produced from extracted sawdust: effect of cooling conditions and binder addition on composition, mechanical and thermochemical properties. Biomass Bioenergy, 2022, 164 106562

[63] Shankar Tumuluru J, Sokhansanj S, Hess JR, Wright CT, Boardman RD. Review: a review on biomass torrefaction process and product properties for energy applications. Ind Biotechnol, 2011, 7(5): 384-401

[64] Singh B, Korstad J, Guldhe A, Kothari R. Editorial: emerging feedstocks & clean technologies for lignocellulosic biofuel [Editorial]. Front Energy Res, 2022

[65] Solarte-Toro JC, González-Aguirre JA, Poveda Giraldo JA, Cardona Alzate CA. Thermochemical processing of woody biomass: a review focused on energy-driven applications and catalytic upgrading. Renew Sustain Energy Rev, 2021, 136 110376

[66] Song B, Cooke-Willis M, Theobald B, Hall P. Producing a high heating value and weather resistant solid fuel via briquetting of blended wood residues and thermoplastics. Fuel, 2021, 283 119263

[67] Srivastava RK, Sarangi PK, Shadangi KP, Sasmal S, Gupta VK, Govarthanan M, Sahoo UK, Subudhi S. Biorefineries development from agricultural byproducts: value addition and circular bioeconomy. Sustain Chem Pharm, 2023, 32 100970

[68] Stafford W, De Lange W, Nahman A, Chunilall V, Lekha P, Andrew J, Johakimu J, Sithole B, Trotter D. Forestry biorefineries. Renew Energy, 2020, 154: 461-475

[69] Suckling ID, Jack MW, Lloyd JA, Murton KD, Newman RH, Stuthridge TR, Torr KM, Vaidya AA. A mild thermomechanical process for the enzymatic conversion of radiata pine into fermentable sugars and lignin. Biotechnol Biofuels, 2017, 10(1): 61

[70] Sulis DB, Lavoine N, Sederoff H, Jiang X, Marques BM, Lan K, Cofre-Vega C, Barrangou R, Wang JP. Advances in lignocellulosic feedstocks for bioenergy and bioproducts. Nat Commun, 2025, 16(11244

[71] Sun Z, Fridrich B, de Santi A, Elangovan S, Barta K. Bright side of lignin depolymerization: toward new platform chemicals. Chem Rev, 2018, 118(2614-678

[72] TAPPI. (1991). TAPPI useful method UM 250 acid-soluble lignin in wood and pulp. In.

[73] TAPPI. (2002). Standard method, T 222 Acid-insoluble lignin in wood and pulp om-88. In.

[74] Teleman A, Lundqvist J, Tjerneld F, Stålbrand H, Dahlman O. Characterization of acetylated 4-O-methylglucuronoxylan isolated from aspen employing 1H and 13C NMR spectroscopy. Carbohydr Res, 2000, 329(4): 807-815

[75] Titirici M-M, Antonietti M, Baccile N. Hydrothermal carbon from biomass: a comparison of the local structure from poly- to monosaccharides and pentoses/hexoses. Green Chem, 2008, 10(11): 1204-1212

[76] Venkata Mohan S, Nikhil GN, Chiranjeevi P, Nagendranatha Reddy C, Rohit MV, Kumar AN, Sarkar O. Waste biorefinery models towards sustainable circular bioeconomy: critical review and future perspectives. Bioresour Technol, 2016, 215: 2-12

[77] Wijeyekoon SLJ, Vaidya AA. Woody biomass as a potential feedstock for fermentative gaseous biofuel production. World J Microbiol Biotechnol, 2021, 37(8134

[78] Wiranarongkorn K, Im-orb K, Patcharavorachot Y, Maréchal F, Arpornwichanop A. Comparative techno-economic and energy analyses of integrated biorefinery processes of furfural and 5-hydroxymethylfurfural from biomass residue. Renew Sustain Energy Rev, 2023, 175 113146

[79] Zhao Y, Zhao X, Iida I, Guo J. Studies on pre-treatment by compression for wood impregnation part II: the impregnation of wood compressed at different moisture content conditions. J Wood Sci, 2019, 65(128

Funding

Ministry of Business, Innovation and Employment(Strategic Science Investment Fund (SSIF))

RIGHTS & PERMISSIONS

The Author(s)