Waste and Biomass Valorization

, Volume 9, Issue 10, pp 1795–1804 | Cite as

The Effect of the Addition of Acetic Acid to Aqueous Ionic Liquid Mixture Using Microwave-assisted Pretreatment in the Saccharification of Napier Grass

  • Akarin Boonsombuti
  • Rinrat Wanapirom
  • Apanee LuengnaruemitchaiEmail author
  • Sujitra Wongkasemjit
Original Paper


Napier grass, Pennisetum purpureum cv. Pakchong 1, was pretreated in an ionic liquid mixture through microwave irradiation. To improve the fermentable sugar yield, an acid catalyzed aqueous ionic liquid pretreatment was applied to maximize the total sugar conversion of pretreated Napier grass. Additionally, to optimize the fermentable sugar yield, experiments were carried out employing response surface methodology (RSM). The study showed that a maximum fermentable sugar concentration of 15.72 g/L could be predicted from the model when Napier grass was pretreated by 1-ethyl-3-methylimidazolium acetate ([EMIM] [OAc]) 50% (v/v) aqueous mixture combined with 1.287% (v/v) acetic acid at a microwave pretreatment temperature and time of 147 °C and 76 min, respectively. The experiments confirmed that the maximum sugar concentration obtained from acidic aqueous ionic liquid pretreatment were 14.38 g/L under the optimal conditions. The results from the Fourier transmission infrared spectroscopic showed that an acid catalyzed aqueous ionic liquid pretreatment removed large fractions of lignin.


Ionic liquid Lignocellulosic biomass Napier grass Pretreatment RSM 



The authors would like to express their sincere gratitude to Prof. Dr. Tharapong Vitidsant for the Napier grass samples and National Research University Project, Office of Higher Education Commission (WCU-037-EN-57) for financial support. The authors also gratefully acknowledge the financial support provided by the Methee-Vijai-Chula Grant, Grant for International Research Integration: Chula-Research Scholar, Ratchadaphiseksompote Endowment Fund, Chulalongkorn University.


  1. 1.
    Kumar, P., Barrett, D.M., Delwiche, M.J., Stroeve, P.: Methods for pretreatment of lignocellulosic biomass for efficient hydrolysis and biofuel production. Ind. Eng. Chem. Res. 48(8), 3713–3729 (2009)CrossRefGoogle Scholar
  2. 2.
    Holm, J., Lassi, L.: Ionic liquids in the pretreatment of lignocellulosic biomass. In: Kokorin, A. (ed.) Ionic Liquids: Applications and Perspectives, pp. 545–560. InTech (2011). doi: 10.5772/14774
  3. 3.
    Brodeur, G., Yau, E., Badal, K., Collier, J., Ramachandran, K.B., Ramakrishnan, S.: Chemical and physicochemical pretreatment of lignocellulosic biomass: a review. Enzyme Res. 2011, 787532 (2011). doi: 10.4061/2011/787532 CrossRefGoogle Scholar
  4. 4.
    Chen, Y., Stevens, M.A., Zhu, Y.M., Holmes, J., Xu, H.: Understanding of alkaline pretreatment parameters for corn stover enzymatic saccharification. Biotechnol. Biofuels 6 (2013). doi: 10.1186/1754-6834-6-8
  5. 5.
    Simmons, B.A., Singh, S., Holmes, B.M., Blanch, H.W.: Ionic liquid pretreatment. Chem. Eng. Prog. 106(3), 50–55 (2010)Google Scholar
  6. 6.
    Castro, M.C., Rodriguez, H., Arce, A., Soto, A.: Mixtures of ethanol and the ionic liquid 1-ethyl-3-methylimidazolium acetate for the fractionated solubility of biopolymers of lignocellulosic biomass. Ind. Eng. Chem. Res. 53(29), 11850–11861 (2014). doi: 10.1021/ie501956x CrossRefGoogle Scholar
  7. 7.
    Castro, M.C., Arce, A., Soto, A., Rodriguez, H.: Thermophysical characterization of the mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate with 1-propanol or 2-propanol. J. Chem. Eng. Data. 61(7), 2299–2310 (2016). doi: 10.1021/acs.jced.5b01023 CrossRefGoogle Scholar
  8. 8.
    Clough, M.T., Geyer, K., Hunt, P.A., Mertes, J., Welton, T.: Thermal decomposition of carboxylate ionic liquids: trends and mechanisms. Phys. Chem. Chem. Phys. 15(47), 20480–20495 (2013). doi: 10.1039/c3cp53648c CrossRefGoogle Scholar
  9. 9.
    B, S.: Ionic liquid pretreatment. Accessed 24 June 2014 2014
  10. 10.
    Dadi, A.P., Schall, C.A., Varanasi, S.: Mitigation of cellulose recalcitrance to enzymatic hydrolysis by ionic liquid pretreatment. Appl. Biochem. Biotechnol. 137, 407–421 (2007). doi: 10.1007/s12010-007-9068-9 Google Scholar
  11. 11.
    Lee, S.H., Doherty, T.V., Linhardt, R.J., Dordick, J.S.: Ionic liquid-mediated selective extraction of lignin from wood leading to enhanced enzymatic cellulose hydrolysis. Biotechnol. Bioeng. 102(5), 1368–1376 (2009). doi: 10.1002/bit.22179 CrossRefGoogle Scholar
  12. 12.
    Cox, B., Ekerdt, J.: Catalytic transformation of biomass in ionic liquids. In: Fang, Z., Smith, J.R.L., Qi, X. (eds.) Production of Biofuels and Chemicals with Ionic Liquids, vol. 1. Biofuels and Biorefineries, pp. 195–222. Springer, Netherlands (2014)CrossRefGoogle Scholar
  13. 13.
    Ha, S.H., Ngoc, L.M., An, G.M., Koo, Y.M.: Microwave-assisted pretreatment of cellulose in ionic liquid for accelerated enzymatic hydrolysis. Bioresour. Technol. 102(2), 1214–1219 (2011). doi: 10.1016/j.biortech.2010.07.108 CrossRefGoogle Scholar
  14. 14.
    Qing, Q., Hu, R., He, Y.C., Zhang, Y., Wang, L.Q.: Investigation of a novel acid-catalyzed ionic liquid pretreatment method to improve biomass enzymatic hydrolysis conversion. Appl. Microbiol. Biotechnol. 98(11), 5275–5286 (2014). doi: 10.1007/s00253-014-5664-0 CrossRefGoogle Scholar
  15. 15.
    Zhang, Z.Y., O’Hara, I.M., Doherty, W.U.S.: Pretreatment of sugarcane bagasse by acid-catalysed process in aqueous ionic liquid solutions. Bioresour. Technol. 120, 149–156 (2012). doi: 10.1016/j.biortech.2012.06.035 CrossRefGoogle Scholar
  16. 16.
    Department of Alternative Energy Development and Efficiency, M.o.E.: Napier grass. (2015)
  17. 17.
    Yasuda, M., Ishii, Y., Ohta, K.: Napier grass (Pennisetum purpureum Schumach) as raw material for bioethanol production: pretreatment, saccharification, and fermentation. Biotechnol. Bioprocess Eng. 19(6), 943–950 (2014). doi: 10.1007/s12257-014-0465-y CrossRefGoogle Scholar
  18. 18.
    Phitsuwan, P., Sakka, K., Ratanakhanokchai, K.: Structural changes and enzymatic response of Napier grass (Pennisetum purpureum) stem induced by alkaline pretreatment. Bioresour. Technol. 218, 247–256 (2016). doi: 10.1016/j.biortech.2016.06.089 CrossRefGoogle Scholar
  19. 19.
    Takata, E., Tsutsumi, K., Tsutsumi, Y., Tabata, K.: Production of monosaccharides from napier grass by hydrothermal process with phosphoric acid. Bioresour. Technol. 143, 53–58 (2013). doi: 10.1016/j.biortech.2013.05.112 CrossRefGoogle Scholar
  20. 20.
    Li, Q., He, Y.C., Xian, M., Jun, G., Xu, X., Yang, J.M., Li, L.Z.: Improving enzymatic hydrolysis of wheat straw using ionic liquid 1-ethyl-3-methyl imidazolium diethyl phosphate pretreatment. Bioresour. Technol. 100(14), 3570–3575 (2009). doi: 10.1016/j.biortech.2009.02.040 CrossRefGoogle Scholar
  21. 21.
    Li, C.L., Knierim, B., Manisseri, C., Arora, R., Scheller, H.V., Auer, M., Vogel, K.P., Simmons, B.A., Singh, S.: Comparison of dilute acid and ionic liquid pretreatment of switchgrass: biomass recalcitrance, delignification and enzymatic saccharification. Bioresour. Technol. 101(13), 4900–4906 (2010). doi: 10.1016/j.biortech.2009.10.066 CrossRefGoogle Scholar
  22. 22.
    Segal, L., Creely, J.J., Martin, A.E., Conrad, C.M.: An empirical method for estimating the degree of crystallinity of native cellulose using the X-ray diffractometer. Text. Res. J. 29(10), 786–794 (1959). doi: 10.1177/004051755902901003 CrossRefGoogle Scholar
  23. 23.
    Sasikumar, E., Viruthagiri, T.: Optimization of process conditions using response surface methodology (RSM) for ethanol production from pretreated sugarcane bagasse: kinetics and modeling. Bioenerg. Res. 1(3–4), 239–247 (2008). doi: 10.1007/s12155-008-9018-6 CrossRefGoogle Scholar
  24. 24.
    Weerachanchai, P., Leong, S.S., Chang, M.W., Ching, C.B., Lee, J.M.: Improvement of biomass properties by pretreatment with ionic liquids for bioconversion process. Bioresour. Technol. 111, 453–459 (2012). doi: 10.1016/j.biortech.2012.02.023 CrossRefGoogle Scholar
  25. 25.
    Kimon, K.S., Alan, E.L., Sinclair, D.W.O.: Enhanced saccharification kinetics of sugarcane bagasse pretreated in 1-butyl-3-methylimidazolium chloride at high temperature and without complete dissolution. Bioresour. Technol. 102(19), 9325–9329 (2011). doi: 10.1016/j.biortech.2011.07.072 CrossRefGoogle Scholar
  26. 26.
    Gong, G.F., Liu, D.Y., Huang, Y.D.: Microwave-assisted organic acid pretreatment for enzymatic hydrolysis of rice straw. Biosyst. Eng. 107(2), 67–73 (2010). doi: 10.1016/j.biosystemseng.2010.05.012 CrossRefGoogle Scholar
  27. 27.
    Tran, D.T., Yet-Pole, I., Lin, C.W.: Developing co-culture system of dominant cellulolytic Bacillus sp THLA0409 and dominant ethanolic Klebsiella oxytoca THLC0409 for enhancing ethanol production from lignocellulosic materials. J. Taiwan Inst. Chem. Eng. 44(5), 762–769 (2013). doi: 10.1016/j.jtice.2013.01.028 CrossRefGoogle Scholar
  28. 28.
    Anderson, W.F., Dien, B.S., Brandon, S.K., Peterson, J.D.: Assessment of bermudagrass and bunch grasses as feedstock for conversion to ethanol. Appl. Biochem. Biotechnol. 145(1–3), 13–21 (2008). doi: 10.1007/s12010-007-8041-y CrossRefGoogle Scholar
  29. 29.
    Klemm, D., Heublein, B., Fink, H.P., Bohn, A.: Cellulose: fascinating biopolymer and sustainable raw material. Angew Chem-Int Edit. 44(22), 3358–3393 (2005). doi: 10.1002/anie.200460587 CrossRefGoogle Scholar
  30. 30.
    Wongwatanapaiboon, J., Kangvansaichol, K., Burapatana, V., Inochanon, R., Winayanuwattikun, P., Yongvanich, T., Chulalaksananukul, W.: The potential of cellulosic ethanol production from grasses in thailand. J. Biomed. Biotechnol. 2012(12), 1–10 (2012)CrossRefGoogle Scholar
  31. 31.
    Samayam, I.P., Schall, C.A.: Saccharification of ionic liquid pretreated biomass with commercial enzyme mixtures. Bioresour. Technol. 101(10), 3561–3566 (2010)CrossRefGoogle Scholar
  32. 32.
    Li, C., Knierim, B., Manisseri, C., Arora, R., Scheller, H.V., Auer, M., Vogel, K.P., Simmons, B.A., Singh, S.: Comparison of dilute acid and ionic liquid pretreatment of switchgrass: biomass recalcitrance, delignification and enzymatic saccharification. Bioresour. Technol. 101(13), 4900–4906 (2010). doi: 10.1016/j.biortech.2009.10.066 CrossRefGoogle Scholar
  33. 33.
    Boonsombuti, A., Luengnaruemitchai, A., Wongkasemjit, S.: Enhancement of enzymatic hydrolysis of corncob by microwave-assisted alkali pretreatment and its effect in morphology. Cellulose 20(4), 1957–1966 (2013). doi: 10.1007/s10570-013-9958-7 CrossRefGoogle Scholar
  34. 34.
    Zhang, J., Wang, Y., Zhang, L., Zhang, R., Liu, G., Cheng, G.: Understanding changes in cellulose crystalline structure of lignocellulosic biomass during ionic liquid pretreatment by XRD. Bioresour. Technol. 151, 402–405 (2014). doi: 10.1016/j.biortech.2013.10.009 CrossRefGoogle Scholar
  35. 35.
    Nelson, M.L., O’Connor, R.T.: Relation of certain infrared bands to cellulose crystallinity and crystal latticed type. Part I. Spectra of lattice types I, II, III and of amorphous cellulose. J. Appl. Polym. Sci. 8(3), 1311–1324 (1964). doi: 10.1002/app.1964.070080322 CrossRefGoogle Scholar
  36. 36.
    Hurtubise, F.G., Krassig, H.: Classification of fine structural characteristics in cellulose by infared spectroscopy. Use of potassium bromide pellet technique. Anal. Chem. 32(2), 177–181 (1960). doi: 10.1021/ac60158a010 CrossRefGoogle Scholar
  37. 37.
    Oh, S.Y., Yoo, D.I., Shin, Y., Kim, H.C., Kim, H.Y., Chung, Y.S., Park, W.H., Youk, J.H.: Crystalline structure analysis of cellulose treated with sodium hydroxide and carbon dioxide by means of X-ray diffraction and FTIR spectroscopy. Carbohydr. Res. 340(15), 2376–2391 (2005). doi: 10.1016/j.carres.2005.08.007 CrossRefGoogle Scholar
  38. 38.
    Duan, X., Zhang, C., Ju, X., Li, Q., Chen, S., Wang, J., Liu, Z.: Effect of lignocellulosic composition and structure on the bioethanol production from different poplar lines. Bioresour. Technol. 140, 363–367 (2013). doi: 10.1016/j.biortech.2013.04.101 CrossRefGoogle Scholar
  39. 39.
    Sun, N., Rahman, M., Qin, Y., Maxim, M.L., Rodriguez, H., Rogers, R.D.: Complete dissolution and partial delignification of wood in the ionic liquid 1-ethyl-3-methylimidazolium acetate. Green Chem. 11(5), 646–655 (2009). doi: 10.1039/b822702k CrossRefGoogle Scholar
  40. 40.
    Hosseinaei, O., Wang, S.Q., Rials, T.G., Xing, C., Zhang, Y.: Effects of decreasing carbohydrate content on properties of wood strands. Cellulose 18(3), 841–850 (2011). doi: 10.1007/s10570-011-9519-x CrossRefGoogle Scholar
  41. 41.
    Jidapa Manaso, A.L., Sujitra Wongkasemjit: Optimization of two-stage pretreatment combined with microwave radiation using response surface methodology. Int. J. Chem. Mol. Nucl. Mater. Metall. Eng. 7, 191–196 (2013)Google Scholar
  42. 42.
    Qiu, Z., Aita, G.M., Walker, M.S.: Effect of ionic liquid pretreatment on the chemical composition, structure and enzymatic hydrolysis of energy cane bagasse. Bioresour. Technol. 117, 251–256 (2012). doi: 10.1016/j.biortech.2012.04.070 CrossRefGoogle Scholar
  43. 43.
    Mood, S.H., Golfeshan, A.H., Tabatabaei, M., Abbasalizadeh, S., Ardjmand, M.: Comparison of different ionic liquids pretreatment for barley straw enzymatic saccharification. 3 Biotech 3(5), 399–406 (2013). doi: 10.1007/s13205-013-0157-x CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2017

Authors and Affiliations

  • Akarin Boonsombuti
    • 1
  • Rinrat Wanapirom
    • 2
  • Apanee Luengnaruemitchai
    • 2
    Email author
  • Sujitra Wongkasemjit
    • 2
  1. 1.Department of General Science, Faculty of ScienceSrinakharinwirot UniversityBangkokThailand
  2. 2.The Petroleum and Petrochemical CollegeChulalongkorn UniversityBangkokThailand

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