Milagres, Adriane M. F.

Monte, J. R.

Mussatto, Solange I.

Universidade do Minho: RepositoriUM

Modifications on sugarcane bagasse fibers after SPORL pretreatment at different temperatures

 MODIFICATIONS ON SUGARCANE BAGASSE FIBERS AFTER  SPORL PRETREATMENT AT DIFFERENT TEMPERATURES  Joseana R. Monte 1; Adriane M. F. Milagres 1; Solange I. Mussatto 2,*  1 Engineering School of Lorena, University of São Paulo, Lorena/SP, Brazil. 2 Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal. * E-mail address: solange@deb.uminho.pt  Key words: Sugarcane bagasse; SPORL; fibers    Introduction. Sugarcane bagasse is a lignocellulosic feedstock of interest for cellulosic ethanol production because of its high productivity, low inputs, and positive environmental effects. Processes and platforms that can efficiently and economically convert lignocellulosic biomass to ethanol are still deficient. In this study, the SPORL (sulfite pretreatment to overcome recalcitrance of lignocelluloses) process was proposed for sugarcane bagasse pretreatment. This process is reported to cause changes on biomass fiber surface, such as reduction of the polymerization degree, removal of the hemicellulose and lignin sulfonation, making the biomass more susceptible for further enzymatic saccharification (1). The objective of this study was to evaluate the modifications occurred in the sugarcane bagasse fibers after SPORL pretreatment at different temperatures.  Methods. Different samples of sugarcane bagasse were pretreated with a solution of Na2SO3 5% (g reagent/g biomass), pH 2.1 (adjusted with H2SO4), at 130, 150 and 160 °C, for 2 h. Subsequently, the pretreated material was refined in an industrial blender, washed and dried at room temperature. The percentage of cellulose, hemicellulose and lignin was determined as described by Ferraz et al. (2). The samples were also characterized regarding the contents of sulfonic groups (SG), water retention (WRV), SEM, FITR and XRD.  Results.   Table 1. Chemical characterization of sugarcane bagasse samples pretreated with acid sulfite at different temperatures. Samples T (°C) Y (%) C H L VC in natura 100.0 43.7 27.3 24.4 130 73.2 31.5 15.6 18.5 150 78.1 39.4 12.6 18.4 160 70.7 40.3 6.4 15.2 H89 in natura 100.0 43.6 29.5 18.2 130 85.4 33.5 21.4 17.0 150 65.7 33.4 11.7 12.0 160 65.0 37.5 8.0 12.4 H146 in natura 100.0 41.9 32.4 19.0 130 78.0 31.3 20.9 17.0 150 82.2 33.2 20.5 17.0 160 64.9 38.2 7.4 13.6 H166 in natura 100.0 44.0 32.1 20.0 130 87.1 33.8 23.3 20.5 150 70.8 39.5 9.4 14.9 160 71.3 38.3 9.4 15.2 T: temperature; Y: pretreatment yield; C: cellulose (g/100g biomass); H: hemicellulose (g/100g biomass); L: lignin (g/100g biomass). The SPORL process was able to remove over 70% of hemicellulose and 20% of lignin present in all the sugarcane bagasse samples (Table 1). Among the tested samples, H146 showed the best correlation between the variables. The temperature increase caused an increase in the sulfonation degree of the residual lignin, while the water retention (WRV) was decreased (Fig 1). The crystallinity of the H146 sample was increased (Fig 2) with the hemicellulose removal increase.                Fig.1. Analysis of sulfonic groups and water retention of sugarcane bagasse H146 pretreated with acid sulfite at different temperatures.              Fig.2. X-Ray of sugarcane bagasse H146 pretreated with acid sulfite at different temperatures. Black: in natura; green: 130 °C, blue: 150 °C and cyan: 160 °C.  Conclusions. This study demonstrated that the temperature increase leads to a greater removal of hemicellulose, main change on sugarcane fiber able to directly influence the other variables.  Acknowledgements. This work was supported by CNPq (240604/2012-1) and CAPES.  References   1. Zhu JY, Pan XJ, Wang GS, Gleisner R. (2009). Bioresource Technol. 100:2411-2418. 2. Ferraz A, Baeza J, Rodriguez J, Freer J. (2000). Bioresource Technol.74:201-212. 050100150200250300130 150 160GS (mmol/g of lignin)WRV (%)Temperature (°C)H14605010015020025030035040010 15 20 25 30Intensity (cps)2θH146

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Modifications on sugarcane bagasse fibers after SPORL pretreatment at different temperatures

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Universidade do Minho: RepositoriUM

Universidade do Minho: RepositoriUM