Effect of Pretreatment of Alkali Combined with Acid on Ethanol Conversion Rate of Cellulose from Rice Straw

Acetic acid,hydrogen peroxide,acetic acid-hydrogen peroxide(PPA),and sodium hydroxide-PAA were used for pretreatment of rice straw at normal pressure and temperature.Cellulase and yeast were added for ethanol production by asynchronous fermentation.The experimental results showed that the solid yield after pretreatment of alkali combined with acid was much lower than that after pretreatment with either acetic acid or hydrogen peroxide.The solid yield demonstrated a negative correlation trend with the hydrolytic glucose concentration.The sodium hydroxide-PAA pretreatment could effectively remove the lignin and enhance the hydrolysis rate of cellulose as well as the ethanol conversion rate.It was found that the process of pretreating rice straw with 5% sodium hydroxide-PAA at 90 ℃ for 1.5 h could be replaced by soaking rice straw in 10% sodium hydroxide-PAA at room temperature for 48 h.