The present work explores the potential of wet air oxidation (WAO) for pretreatment of mixed lignocellulosic biomass to enhance enzymatic convertibility. Rice husk and wheat straw mixture (1:1 mass ratio) was used as a model mixed lignocellulosic biomass. Post-WAO treatment, cellulose recovery in the solid fraction was in the range of 86% to 99%, accompanied by a significant increase in enzymatic hydrolysis of cellulose present in the solid fraction. The highest enzymatic conversion efficiency, 63% (by weight), was achieved for the mixed biomass pretreated at 195 °C, 5 bar, 10 minutes compared to only 19% in the untreated biomass. The pretreatment under the aforesaid condition also facilitated 52% lignin removal and 67% hemicellulose solubilization. A statistical design of experiments on WAO process conditions was conducted to understand the effect of process parameters on pretreatment, and the predicted_x000D_ responses were found to be in close agreement with the experimental data. Enzymatic hydrolysis experiments with WAO liquid fraction as diluent showed favorable results with sugar enhancement up to 10.4 g L-1.

Wet Air Oxidation Pretreatment Enzymatic Hydrolysis Recycled Liquid Fraction Lignocellulosic Biomass

Ravikumar R, Ranganathan BV, Chathoth KN, Gobikrishnan S, Korean J. Chem. Eng., 30(5), 1051 (2013)
Balat M, Balat H, Oz C, Prog. Energy Combust. Sci., 34, 551 (2008)
Gunatilake H, H India: Study on Cross-Sectoral Implications of Biofuel Production and Use. Final Report of TA 7250-IND (2011)
Bhojvaid PP, Biofuels: Towards a greener and secure energy future. TERI Press (2006)
Licht FO, World Ethanol Market: The Outlook to 2015, Tunbridge Wells, Agra Europe Special Report, UK (2006)
Sukumaran RK, Surender VJ, Sindhu R, Binod P, Janu KU, Sajna KV, Rajasree KP, Pandey A, Bioresour. Technol., 101(13), 4826 (2010)
Berlin A, Balakshin M, Gilkes N, Kadla J, Maximenko V, Kubo S, Saddler J, J. Biotechnol., 125, 198 (2006)
Menon V, Rao M, Prog. Energy. Combust. Sci., 38, 522 (2012)
Kumar P, Barrett DM, Delwiche MJ, Stroeve P, Ind. Eng. Chem. Res., 48(8), 3713 (2009)
Han M, Kim Y, Kim Y, Chung B, Choi GW, Korean J. Chem. Eng., 28(1), 119 (2011)
Bjerre AB, Olesen AB, Fernqvist T, Ploger A, Schmidt AS, Biotechnol. Bioeng., 49(5), 568 (1996)
Ravikumar R, Ranganathan BV, Chathoth KN, Gobikrishnan S, Korean J. Chem. Eng., 30(5), 1051 (2013)
Schmidt AS, Thomsen AB, Bioresour. Technol., 64, 139 (1995)
Mishra VS, Mahajani VV, Joshi JB, Ind. Eng. Chem. Res., 34(1), 2 (1995)
Banerjee S, Sen R, Pandey RA, Chakrabarti T, Satpute D, Giri BS, Mudliar S, Biomass Bioenerg., 33(12), 1680 (2009)
Ayeni AO, Banerjee S, Omoleye JA, Hymore FK, Giri BS, Deshmukh SC, Pandey RA, Mudliar SN, Biomass Bioenerg., 48, 130 (2013)
Alvira P, Tomas-Pejo E, Ballesteros M, Negro MJ, Bioresour. Technol., 101(13), 4851 (2010)
Simmons TJ, Lee SH, Miao J, Miyauchi M, Park TJ, Bale SS, Linhardt RJ, Wood Sci Technol., 45, 719 (2011)
Sluiter A, Hames B, Ruiz R, Scarlata C, Wooley R, Sluiter J, Golden, CO: National Renewable Energy Laboratory, NREL/TP-510-42618 (2008)
Miller GL, Anal. Chem., 31, 426 (1959)
Banerjee S, Sen R, Mudliar S, Pandey RA, Chakrabarti T, Satpute D, Biotechnol. Prog., 27(3), 691 (2011)
Kwak KO, Jung SJ, Chung SY, Kang CM, Huh YI, Bae SO, Biochem. Eng J., 31, 1 (2006)
Klinke HB, Ahring BK, Schmidt AS, Thomsen AB, Bioresour. Technol., 82(1), 15 (2002)
Palonen H, Thomsen AB, Tenkanen M, Schmidt AS, Viikari U, Appl. Biochem. Biotechnol., 117(1), 1 (2004)
Martin C, Marcet M, Thomsen AB, Bioresources, 3, 670 (2008)
Fayyaz-ur-Rehman M, Tariq MI, Aslam M, Khadija G, Iram A, Open Enzym Inhib J., 2, 8 (2009)
Kristensen JB, Felby C, Jørgensen H, Appl. Biochem. Biotechnol., 156(1-3), 127 (2009)