(482f) Organosolv Pretreatment of Hybrid Pennisetum for the Production of Lignin and Enzymatically Digestible Cellulose

Four different types of solvents were evaluated for organosolv pretreatment with hybrid pennisetum. Under lower temperature (100 degrees C, 50mM H2SO4 as catalyst), the yields of delignification with acetone, ethanol, GVL and tetrahydrofurfuryl alcohol were 32.8%, 37.6%, 43.2% and 50.2%, respectively, and which results were consistent with the predicts of Hansen solubility parameters. Moreover, a parametric study using tetrahydrofurfuryl alcohol and focusing on acid catalyst dose, temperature, reaction time and solid-liquid ratio were performed to determine their influence on delignification, xylan hydrolysis, and enzymatic cellulose digestibility. Major process parameters were found to be temperature and acid dose. Optimisation of the process towards delignification resulted in a maximum lignin removal rate was 98.1% under 120 degrees C, 50mM H2SO4 as catalyst, solid-liquid ratio 1:12 and reaction time 2 h, and the cellulose retention rate was 86.1%. The digestibility of cellulose rich residues after pretreatment was approximately 99.0%, which was 2.6 times as much as that of the untreated raw material. The composition and structure of the raw materials, the pretreated residues and recovered lignin were analyzed by SEM, XRD, FT-IR, TGA and HSQC. The results indicated that the pretreatment of organosolvs could enhance the enzymatic hydrolysis of lignocellulosic by effectively removing lignin and hemicellulose, then destroying smooth surface structure of raw materials. And the characterization results of recovered lignin indicate that the lignin molecules have undergone significant bond breakage during pretreatment.

KEYWORDS:

Organosolv pretreatment; Enzymatic hydrolysis; Recovered lignin