Addition of Peracetic Acid to Dilute Acid Pretreatment of Biomass Enhances Enzymatic Digestibility

Pretreatment of biomass with dilute acid requires high temperatures of higher than 160°C to remove xylan. However, it does not remove lignin, the main cause for recalcitrance in lignocellulosic biomass. Hyeong Rae Lee of Seoul National University in South Korea now reports that the addition of peracetic acid, a strong oxidant, to mild dilute acid pretreatment reduces the temperature requirement.

Pretreatment of yellow poplar with peracetic acid (300 mM) and dilute sulfuric acid (100 mM) at 120°C for 5 min removed 85.7% of the xylan and 90.4% of the lignin, leaving a solid consisting of 75.6% glucan, 6.0% xylan and 4.7% lignin. The solid was then converted to glucose, with an 84.0% yield. This amount of glucose was 2.5 times higher than with dilute acid-pretreated solid and 13.8 times higher than with untreated yellow poplar.

The addition of peracetic acid, which is easily generated from acetic acid and hydrogen peroxide, significantly increases the effect of dilute acid pretreatment of lignocellulosic biomass.