Lignocellulosic Biomass: Analysis Of Pearl Millet Biomass

Lignocellulosic biomass consists of cellulose, hemicellulose, lignin, proteins, acids, salts and minerals. Chemical composition is also one of the important factors for biofuel production. Moisture content of raw pearl millet biomass was (8 %) and ash content (6.27 %) was obviously higher than that the literature report of 3.8 % (Dhabhai et al., 2012). The proximate analysis of pearl millet biomass revealed that moisture (8±0.32%), ash (6.27±0.08%), total solids (92±0.14%), water extractives (6.43±0.12), ethanol extractives (5.72±0.34), cellulose (41.6±0.16%), hemicellulose (22.32 ± 0.65), glucan (28.47±2.88%), galactan (17.24±0.46), arabinan (3.78±0.04), xylan (5.12±0.46), acid insoluble lignin (16.32±0.49) and acid soluble lignin (5.49±0.08%) …show more content…
The optimized parameters were found to be 16 % ortho- phosphoric acid concentration, 12.5 % total solids loading, 121°C and 3 h. The highest total sugar yield of 0.418g/g of pearl millet biomass, 70.06 % of lignin reduction and 70.67 % of cellulose content increase was obtained for the optimized conditions. The biomass difference between raw and pretreated biomass loss was to solubilization of polymeric components to small dispersed fibers in the hydrolysate. The predicted responses were 0.416 g/g of pearl millet biomass of sugar recovery, 70.68 % cellulose content increase and 70.87 % of lignin removal. A maximum lignin reduction of (70.87 %) and increase of cellulose content (70.68 %) was evident from the optimized pretreatment conditions. The predicted value and experimental values were nearly similar to each other. In the present study, sugar recovery was high in acid pretreated hydrolysate which might be due to degradation of cellulosic fractions (Zhang et al., 2006). The lignin fragments were then dissolved in the liquid phase and resulted in digestibility of the solid fraction. In case of dilute acid pretreated pearl millet biomass recorded 0.120 g / g of biomass sugar recovery which was reported by Krishania (et al., 2010), (0.393 to …show more content…
The sugar yield of 0.234 g/g of pearl millet biomass, 47.70 % of lignin reduction and 49.37 % of cellulose increase was obtained for the optimized conditions. The experimental results are near to predicted value consequently it confirmed the results. Lime pretreated pearl millet biomass recorded a 47.70 % of lignin loss which was higher than those of pretreatments carried out by Xu et al. (2010). In alkaline condition, lignin molecules are converted into negative charge. Calcium ions have positive charge that can be cross linked with lignin molecules ultimately which tend to lignin-calcium complex. This type of complex prevents the breakdown of lignin which might be due to ionization of functional groups like carboxyl, methoxy and hydroxyl groups. In lime pretreatment, lignin loss was very low when compared to other treatment. Sugar recovery was increased with increasing reaction time and lime concentration. After that pretreatment, the surface of the biomass became crispy and soft in nature which indicated the removal of lignin and separation of hemicellulose. The pH of the pretreated slurry was found to be

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