Alkaline post-incubation improves the saccharification of poplar after hydrogen peroxide-acetic acid pretreatment

BackgroundHydrogen peroxide-acetic acid (HPAA) is widely used in pretreatment of lignocellulose because it has a good capability in selective delignification. However, high concentration (more than 60%) of HPAA increases the cost of pretreatment and the risk of explosion. In this work, alkaline post-incubation was employed to decrease the HPAA loading and improve the saccharification of poplar.ResultsPretreatment with 100% HPAA removed 91.0% lignin and retained 89.9% glucan in poplar. After poplar was pretreated by 100% HPAA at 60 degrees C for 2 h, the glucan conversion in enzymatic hydrolysis by cellulase increased to 90.1%. Alkaline incubation reduced the total lignin, surface lignin, and acetyl group of HPAA-pretreated poplar. More than 92% acetyl groups of HPAA-pretreated poplar were removed by alkaline incubation with 1.0% NaOH at 50 degrees C for 1 h. After incubation of 60% HPAA-pretreated poplar with 1.0% NaOH, the glucan conversion enhanced to 95.0%. About 40% HPAA loading in pretreatment was reduced by alkaline incubation without the decrease of glucose yield.ConclusionsAlkaline post-incubation had strong ability on the deacetylation and delignification of HPAA-pretreated poplar, exhibiting a strong promotion on the enzymatic hydrolysis yield. This report represented alkaline incubation reduced the HPAA loading, improved pretreatment safety, exhibiting excellent potential application in saccharification of poplar.