Depolymerization of lignocellulosic biomass during peracetic acid delignification

Some kinds of thinned logs in Korea have been simply used as fuel wood and wood chips due to the limitation in their physical properties. However, there is no significant chemical composition difference between thinned log and mature log with more than 30cm in diameter. Therefore, lignocellulosic biomass in thinned log can also be utilized to produce a cellulosic fiber for basic material industries or bioethanol as an alternative energy source for the limited crude oil. For the pulping or fermentation of the sugars to ethanol, pretreatments as delignification process are required. The objective of the study was to evaluate the influence of the degree of polymerization (DP) of the thinned logs, Mongolian oak (Quercus mongolica) and larch (Larix kaempferi), during peracetic acid delignification. For optimization of the delignification precondition, the chips from thinned logs were pretreated under various peracetic acid conditions. DP of the pretreated cellulosic fibers were evaluated using size-exclusion chromatography with SEC-MALLS. From the DP results, the rates of cellulose chain scission were evaluated as delignification. The hydrolysis and delignification were delayed at the initial period of the pretreatment reaction due to chemical accessibility of peracetic acid on wood chips. After the initial period, the result was clearly showed the kinetic of cellulose hydrolysis that the cellulose hydrolysis was directly proportional to the rate of delignification, and the hydrolysis was accelerated after completing delignification. Acknowledgement: This study was carried out with the support of Forest Science & Technology Projects (Project No. S111314L010130) provided by Korea Forest Service.