Optimization of Microwave-Assisted Pretreatment of Rice Straw with FeCl3 in Combination with H3PO4 for Improving Enzymatic Hydrolysis

  • Bikash Kumar
  • Pradeep Verma


Pretreatment is a key step to alter the recalcitrance structure of lignocellulosic biomass for enhancing enzymatic hydrolysis. Rice straw is an agricultural residue which is one of the potential substrate for ethanol production. In the present work, optimization of microwave-assisted pretreatment of rice straw in FeCl3 solution with H3PO4 was performed. The effect of concentration of FeCl3 and H3PO4 along with pretreatment time was evaluated. The optimal pretreatment condition was found as follows: 250mM FeCl3, 3%H3PO4, 155°C, and 20 minutes. The pretreated pulp was subjected to enzymatic hydrolysis using commercial cellulase for assessing effectiveness of pretreatment system. The maximum saccharification per pulp and per biomass was observed as 98.9% and 66.4%, respectively, under enzyme load of 3 FPU/g of substrate after incubation for 48 h.


Microwave Enzymatic hydrolysis Lignocellulosic biomass Delignification 



The authors acknowledge the financial support provided by Department of Biotechnology, Government of India through project sanction wide no: BT/PR7333/PBD/26/373/2012.


  1. 1.
    Wan C, Li Y (2011) Effectiveness of microbial pretreatment by Ceriporiopsis subvermispora on different biomass feedstocks. Bioresour Technol 102(16):7507–7512CrossRefGoogle Scholar
  2. 2.
    USDA (2017) World Rice Production 2016/2017. Date of Access: 26 June 2017Google Scholar
  3. 3.
    Sawangkeaw R, Ngamprasertsith S (2017) Rice straw as feedstock for biorefineries. In: Timayev A, Kadyrov G (eds) Rice and rice straw: production, cultivation and uses. Nova Science Publishers, New York, pp 141–191Google Scholar
  4. 4.
    Binder JB, Raines RT (2010) Fermentable sugars by chemical hydrolysis of biomass. Proc Natl Acad Sci 107(10):4516–4521CrossRefGoogle Scholar
  5. 5.
    Hideno A, Inoue H, Tsukahara K et al (2009) Wet disk milling pretreatment without sulfuric acid for enzymatic hydrolysis of rice straw. Bioresour Technol 100(10):2706–2711CrossRefGoogle Scholar
  6. 6.
    Bak JS, Ko JK, Han YH et al (2009) Improved enzymatic hydrolysis yield of rice straw using electron beam irradiation pretreatment. Bioresour Technol 100(3):1285–1290CrossRefGoogle Scholar
  7. 7.
    Zhong C, Lau MW, Balan V et al (2009) Optimization of enzymatic hydrolysis and ethanol fermentation from AFEX-treated rice straw. Appl Microbiol Biotechnol 84(4):667–676CrossRefGoogle Scholar
  8. 8.
    Zhang Q, Cai W (2008) Enzymatic hydrolysis of alkali-pretreated rice straw by Trichoderma reesei ZM4-F3. Biomass Bioenergy 32(12):1130–1135CrossRefGoogle Scholar
  9. 9.
    Sumphanwanich J, Leepipatpiboon N, Srinorakutara T (2008) Evaluation of dilute-acid pretreated bagasse, corn cob and rice straw for ethanol fermentation bySaccharomyces cerevisiae. Ann Microbiol 58(2):219–225CrossRefGoogle Scholar
  10. 10.
    Zhao X, Cheng K, Liu D (2009) Organosolv pretreatment of lignocellulosic biomass for enzymatic hydrolysis. Appl Microbiol Biotechnol 82(5):815–827CrossRefGoogle Scholar
  11. 11.
    Chaturvedi V, Verma P (2013) An overview of key pretreatment processes employed for bioconversion of lignocellulosic biomass into biofuels and value added products. 3 Biotech 3(5):415–431CrossRefGoogle Scholar
  12. 12.
    Harmsen P, Huijgen W, López L et al (2010) Literature review of physical and chemical pretreatment processes for lignocellulosic biomass, Food & Biobased Research. Wageningen UR, Food & Biobased Research, Wageningen , pp 1–49Google Scholar
  13. 13.
    Hu Z, Wen Z (2008) Enhancing enzymatic digestibility of switchgrass by microwave-assisted alkali pretreatment. Biochem Eng J 38(3):369–378CrossRefGoogle Scholar
  14. 14.
    Kim HM, Choi YS, Lee DS et al (2017) Production of bio-sugar and bioethanol from coffee residue (CR) by acid-chlorite pretreatment. Bioresour Technol 236:194–201CrossRefGoogle Scholar
  15. 15.
    Verma P, Chaturvedi V (2017) A comparative assessment of autoclave and microwave-assisted peroxometal complex in delignification of wood biomass for enhanced sugar production. In: Pandey KK, Ramakantha V, Chauhan SS et al (eds) Wood is good: current trends and future prospects in wood utilization. Springer, Singapore, pp 383–390CrossRefGoogle Scholar
  16. 16.
    Sindhu R, Binod P, Mathew AK et al (2016) A novel microwave assisted surfactant pretreatment of chili post -harvest residue for the production of bioethanol and biopolymer. Ann Agri Crop Sci 2(1):30–35Google Scholar
  17. 17.
    Verma P, Watanabe T, Honda Y et al (2011) Microwave-assisted pretreatment of woody biomass with ammonium molybdate activated by H2O2. Bioresour Technol 102(4):3941–3945CrossRefGoogle Scholar
  18. 18.
    Liu L, Sun J, Li M et al (2009) Enhanced enzymatic hydrolysis and structural features of corn stover by FeCl3 pretreatment. Bioresour Technol 100(23):5853–5858CrossRefGoogle Scholar
  19. 19.
    Brown L, Torget R (1996) Enzymatic saccharification of lignocellulosic biomass. Chemical analysis and testing task laboratory analytical procedure(LAP)-009, NREL, USA, pp 1–18Google Scholar
  20. 20.
    Miller GL (1959) Use of dinitrosalicylic acid reagent for determination of reducing sugar. Anal Chem 31(3):426–428CrossRefGoogle Scholar
  21. 21.
    Lü J, Zhou P (2011) Optimization of microwave-assisted FeCl3 pretreatment conditions of rice straw and utilization of Trichoderma viride and Bacillus pumilus for production of reducing sugars. Bioresour Technol 102(13):6966–6971CrossRefGoogle Scholar
  22. 22.
    Martín C, De Moraes Rocha GJ, Dos Santos JRA et al (2012) Enzyme loading dependence of cellulose hydrolysis of sugarcane bagasse. Quim Nova 35(10):1927–1930CrossRefGoogle Scholar

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© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Bikash Kumar
    • 1
  • Pradeep Verma
    • 1
  1. 1.Bioprocess and Bioenergy Laboratory, Department of MicrobiologyCentral University of RajasthanAjmerIndia

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