Document Type : Research Article

Author

Department of Chemical Engineering, Faculty of Engineering, University of Isfahan, P. O. Box: 81746-73441, Isfahan, Iran

Abstract

Glycyrrhiza glabra residue (GGR) was efficiently subjected to concentrated phosphoric acid (PA) pretreatment with/without surfactant assistance, and promising results were obtained following separate enzymatic hydrolysis and fermentation (SHF) of the biomass. Pretreatment was carried out using 85 % PA either at 50 or 85 °C with 12.5 % solid loading for 30 min. In parallel experiments, the intact GGR was impregnated in 2 % (w/w) surfactant (Polyethylene glycol) aqueous solution prior to the PA pretreatment. Consequently, the pretreated materials were subjected to enzymatic hydrolysis (50 °C, 72 h) using 25 FPU/g cellulase, and the most digestible biomass was nominated for conversion to bioethanol. Substantial improvement in digestibility of GGR (~92 % hydrolysis yield) was observed following surfactant-assisted PA pretreatment, whereas digestibility yield from the untreated biomass was only 16.1 %. Consequently, the ethanol production form GGR was significantly enhanced by 19.7-fold through separate hydrolysis and fermentation of biomass. Different analytical approaches including water retention value, Simons’ staining, and crystallinity together with FESEM imaging revealed that the improved surface hydrophilicity, increased substrate accessibility to enzyme, and decreased crystallinity could be the major effects of PA pretreatment, leading to higher susceptibility of GGR to enzymatic hydrolysis and subsequent ethanol production.

Keywords

Main Subjects

1.     Yang, B. and Wyman, C.E., "Pretreatment: The key to unlocking low-cost cellulosic ethanol", Biofuels, Bioproducts and Biorefining, Vol. 2, No. 1, (2008), 26-40. (doi: https://doi.org/10.1002/bbb.49).
2.     Taherzadeh, M.J. and Karimi, K., "Pretreatment of lignocellulosic wastes to improve ethanol and biogas production: A review", International Journal of Molecular Sciences, Vol. 9, No. 9, (2008), 1621-1651. (doi:https://doi.org/10.3390/ijms9091621).
3.     Rocha-Meneses, L., Raud, M., Orupõld, K. and Kikas, T., "Potential of bioethanol production waste for methane recovery", Energy, Vol. 173, (2019), 133-139. (doi:https://doi.org/10.1016/j.energy.2019.02.073).
4.     Rajendran, K., Drielak, E., Varma, V.S., Muthusamy, S. and Kumar, G., "Updates on the pretreatment of lignocellulosic feedstocks for bioenergy production-A review", Biomass Conversion and Biorefinery, Vol. 8, No. 2, (2018), 471-483. (doi:https://doi.org/10.1007/s13399-017-0269-3).
5.     Pradhan, P., Mahajani, S.M. and Arora, A., "Production and utilization of fuel pellets from biomass: A review", Fuel Processing Technology, Vol. 181, (2018), 215-232. (doi:https://doi.org/10.1016/j.fuproc. 2018.09.021).
6.     Zabed, H., Sahu, J.N., Boyce, A.N. and Faruq, G., "Fuel ethanol production from lignocellulosic biomass: An overview on feedstocks and technological approaches", Renewable and Sustainable Energy Reviews, Vol. 66, (2016), 751-774. (doi:http://dx.doi.org/10.1016/j.rser. 2016.08.038).
7.     Shafiei, M., Kumar, R. and Karimi, K., Pretreatment of lignocellulosic biomass, In: Lignocellulose-based bioproducts, Springer, (2015).
8.     Kuo. C.-H. and Lee, C.-K., "Enhancement of enzymatic saccharification of cellulose by cellulose dissolution pretreatments", Carbohydrate Polymers, Vol. 77, No. 1, (2009), 41-46. (doi:https://doi.org/10.1016/ j.carbpol.2008.12.003).
9.     Sathitsuksanoh, N., Zhu, Z. and Zhang, Y.-H.P., "Cellulose solvent-based pretreatment for corn stover and avicel: Concentrated phosphoric acid versus ionic liquid [BMIM]Cl", Cellulose, Vol. 19, No. 4, (2012), 1161-1172. (doi:https://doi.org/10.1007/s10570-012-9719-z).
10.   Goshadrou, A., Karimi, K. and Taherzadeh, M.J., "Bioethanol production from sweet sorghum bagasse by Mucor hiemalis", Industrial Crops and Products, Vol. 34, No. 1, (2011), 1219-1225. (doi:https://doi.org/10.1016/j.indcrop.2011.04.018).
11.   Zhang, Y., Cui, J., Lynd, L. and Kuang, L., "A transition from cellulose swelling to cellulose dissolution by o-phosphoric acid: Evidence from enzymatic hydrolysis and supramolecular structure", Biomacromolecules, Vol. 7, No. 2, (2006), 644-648. (doi:https://doi.org/10.1021/bm050799c).
12.   Shafiei, M., Karimi, K. and Taherzadeh, M.J., "Pretreatment of spruce and oak by N-methylmorpholine-N-oxide (NMMO) for efficient conversion of their cellulose to ethanol", Bioresource Technology, Vol. 101, No. 13, (2010), 4914-4918. (doi:https://doi.org/10.1016/ j.biortech.2009.08.100).
13.   Vancov, T., Alston, A.S., Brown, T. and McIntosh, S., "Use of ionic liquids in converting lignocellulosic material to biofuels", Renewable Energy, Vol. 45, (2012), 1-6. (doi:https://doi.org/10.1016/j.renene. 2012.02.033).
14.   Zhang, J., Zhang, B., Zhang, J., Lin, L., Liu, S. and Ouyang, P., "Effect of phosphoric acid pretreatment on enzymatic hydrolysis of microcrystalline cellulose", Biotechnology Advances, Vol. 28, No. 5, (2010), 613-619. (doi:https://doi.org/10.1016/j.biotechadv.2010.05.010).
15.   Goshadrou ,A., "Bioethanol production from cogongrass by sequential recycling of black liquor and wastewater in a mild-alkali pretreatment", Fuel,Vol. 258, (2019), 116141. (doi:https://doi.org/10.1016/ j.fuel.2019.116141).
16.   Goshadrou, A. and Lefsrud, M., "Synergistic surfactant-assisted [EMIM]OAc pretreatment of lignocellulosic waste for enhanced cellulose accessibility to cellulase", Carbohydrate Polymers, Vol. 166, (2017), 104-113. (doi:https://doi.org/10.1016/j.carbpol.2017.02.076).
17.   Nasirpour, N. and Mousavi, S.M., "RSM based optimization of PEG assisted ionic liquid pretreatment of sugarcane bagasse for enhanced bioethanol production: Effect of process parameters", Biomass and Bioenergy,Vol. 116, (2018), 89-98. (doi:https://doi.org/10.1016/ j.biombioe.2018.06.008).
18.   Nasirpour, N., Mousavi, S.M. and Shojaosadati, S.A., "A novel surfactant-assisted ionic liquid pretreatment of sugarcane bagasse for enhanced enzymatic hydrolysis", Bioresource Technology, Vol. 169, (2014), 33-37. (doi:https://doi.org/10.1016/j.biortech.2014.06.023).
19.   Alvira, P., Tomas-Pejo, E., Ballesteros, M. and Negro, M.J., "Pretreatment technologies for an efficient bioethanol production process based on enzymatic hydrolysis: A review", Bioresource Technology, Vol. 101, No. 13, (2010), 4851-4861. (doi:https://doi.org/10.1016/j.biortech.2009.11.093).
20.   Converse, A.O., Matsuno, R., Tanaka, M. and Taniguchi, M., "A model of enzyme adsorption and hydrolysis of microcrystalline cellulose with slow deactivation of the adsorbed enzyme" Biotechnology and Bioengineering, Vol. 32, No. 1, (1988), 38-45. (doi:https://doi.org/10.1002/bit.260320107).
21.   Esteghlalian, A.R., Bilodeau, M., Mansfield, S.D. and Saddler, J.N., "Do enzymatic hydrolyzability and Simons' stain reflect the changes in the accessibility of lignocellulosic substrates to cellulase enzymes ?", Biotechnology Progress, Vol. 17, No. 6, (2001), 1049-1054. (doi:https://doi.org/10.1021/bp0101177).
22.   Grethlein, H.E., "The effect of pore size distribution on the rate of enzymatic hydrolysis of cellulosic substrates", Nature Biotechnology, Vol. 3, No. 2, (1985), 155-160. (doi:https://doi.org/10.1038/nbt0285-155).
23.   Rollin, J.A., Zhu, Z.G., Sathitsuksanoh, N. and Zhang, Y.H.P., "Increasing cellulose accessibility is more important than removing lignin: A comparison of cellulose solvent-based lignocellulose fractionation and soaking in aqueous ammonia", Biotechnology and Bioengineering, Vol. 108, No. 1, (2011), 22-30. (doi:https://doi.org/10.1002/bit.22919).
24.   Kooravand, S., Goshadrou, A. and Hatamipour, M.S., "Enhanced ethanol production from Glycyrrhiza glabra residue by fungus Mucor hiemalis", Industrial Crops and Products, Vol. 108, (2017), 767-774. (doi:https://doi.org/10.1016/j.indcrop.2017.07.030).
25.   Zhang, Y.H.P., Ding, S.Y., Mielenz, J.R., Cui, J.B., Elander, R.T., Laser, M., Himmel, M.E., McMillan, J.R. and Lynd, L.R., "Fractionating recalcitrant lignocellulose at modest reaction conditions", Biotechnology and Bioengineering, Vol. 97, No. 2, (2017), 214-223. (doi:https://doi.org/10.1002/bit.21386).
26.   Chandra, R., Ewanick, S., Hsieh, C. and Saddler, J.N., "The characterization of pretreated lignocellulosic substrates prior to enzymatic hydrolysis, Part 1: A modified Simons' staining technique", Biotechnology Progress, Vol. 24, No. 5, (2008), 1178-1185. (doi:https://doi.org/10.1002/btpr.33).
27.   Goshadrou, A., Karimi, K. and Lefsrud, M., "Characterization of ionic liquid pretreated aspen wood using semi-quantitative methods for ethanol production", Carbohydrate Polymers, Vol. 96, No. 2, (2103), 440-449. (doi:http://dx.doi.org/10.1016/j.carbpol.2013.04.017).
28.   Water retention value of chemical pulps (SCAN-C 62:00), Scandinavian Pulp, Paper, and Board Testing Committee, (2000).
29.   Weiss, N.D., Felby, C. and Thygesen, L.G., "Water retention value predicts biomass recalcitrance for pretreated lignocellulosic materials across feedstocks and pretreatment methods", Cellulose, Vol. 25, No. 6, (2018), 3423-3434. (doi:https://doi.org/10.1007/s10570-018-1798-z).
30.   Luo, X. and Zhu, J.Y., "Effects of drying-induced fiber hornification on enzymatic saccharification of lignocelluloses", Enzyme and Microbial Technology, Vol. 48, No. 1, (2011), 92-99. (doi:https://doi.org/10.1016/ j.enzmictec.2010.09.014).
31.   Chang, K.L., Chen, X.M., Han, Y.J., Wang, X.Q., Potprommanee, L., Ning, X.A., Liu, J.Y., Sun, J., Peng, Y.P., Sun, S.Y. and Lin, Y.C., "Synergistic effects of surfactant-assisted ionic liquid pretreatment rice straw", Bioresource Technology, Vol. 214, (2016), 371-375. (doi:https://doi.org/10.1016/j.biortech.2016.04.113).
32.   Segal, L., Creely, J.J., Martin, A.E. and Conrad, C.M., "An empirical method for estimating the degree of crystallinity of native cellulose using the X-ray diffractometer", Textile Research Journal, Vol. 29, No. 10, (1959), 786-794. (doi:https://doi.org/10.1177/ 004051755902901003).
33.   Goshadrou, A., Karimi, K. and Taherzadeh, M.J., "Ethanol and biogas production from birch by NMMO pretreatment", Biomass and Bioenergy, Vol. 49, (2103), 95-101. (doi:http://dx.doi.org/10.1016/ j.biombioe.2012.12.013).
34.   Zhang, J., Zhang, J., Lin, L., Chen, T., Zhang, J., Liu, S., Li, Z. and Ouyang, P., "Dissolution of microcrystalline cellulose in phosphoric acid-molecular changes and kinetics", Molecules, Vol. 14, No. 12, (2009), 5027-5041. (doi:https://doi.org/10.3390/molecules14125027).
35.   Eken-Saraçoğlu, N., Mutlu, S.F., Dilmaç, G. and Çavuşoğlu, H., "A comparative kinetic study of acidic hemicellulose hydrolysis in corn cob and sunflower seed hull", Bioresource Technology, Vol. 65, (1988), 29-33. (doi:https://doi.org/10.1016/S0960-8524(98)00032-7).
36.   Li, H., Pu, Y., Kumar, R., Ragauskas, A.J. and Wyman, C.E., "Investigation of lignin deposition on cellulose during hydrothermal pretreatment, its effect on cellulose hydrolysis, and underlying mechanisms", Biotechnology and Bioengineering, Vol. 111, No. 3, (2104), 485-492. (doi:https://doi.org/10.1002/bit.25108).
37.   Igarashi, K., Uchihashi, T., Koivula, A., Wada, M., Kimura, S., Okamoto, T., Penttila, M., Ando, T. and Samejima, M., "Traffic jams reduce hydrolytic efficiency of cellulase on cellulose surface", Science, Vol. 333, No. 6047, (2011), 1279-1282. (doi:http://dx.doi.org/10.1126/ science.1208386).
38.   Eriksson, T., Börjesson, J. and Tjerneld, F., "Mechanism of surfactant effect in enzymatic hydrolysis of lignocellulose", Enzyme and Microbial Technology, Vol. 31, No. 3, (2002), 353-364. (doi:https://doi.org/10.1016/S0141-0229(02)00134-5).