Dilute Acid Pretreatment of Paulownia for Bioethanol Production

Dilute sulfuric acid pretreatment of paulownia before cellulose enzymatic hydrolysis was investigated.The biomass with a 10 % solid loading rate was pretreated at 121 ℃ by dilute sulfuric acid with different concentrations(0.5 %,1.0 %,1.5 % and 2.0 %) for 30,60 and 90 min.The concentrations of the total reducing sugars,monosaccharides and inhibitors(e.g.furfural and HMF(5-hydroxymethylfurfural)) in the pre-hydrolyzate were analyzed to obtain the optimum acid hydrolysis condition that did not affecting the flowing enzymatic hydrolysis.The total reducing sugar yield was about 82 % of the theoretical maximum value,and the conversion efficiencies for glucan and xylan were 39.5 % and 48.7 %,respectively,when the biomass was pretreated by 1.5 % sulfuric acid for 60 min.