15-14: Bio-modification of functional groups in organosolv lignin by white rot fungus, Fomitopsis insularis

Lignin is a major component of lignocellulosic biomass. It consisted of abundant phenyl propanoids in nature. In bioethanol production, lignin is produced as a co-product and has been considered as a low valued by-product. However, lignin has a great potential for commercial usage in value added applications. Especially, organosolv lignin derived from ethanol-water delignification, which is relatively pure and sulfur free, and has a low molecular weight with less condensation than other conventional lignin preparations. These properties allow microorganisms to easily access and modify organosolv lignin.

The objectives of this study were to examine functional group modification of organosolv lignin by Fomitopsis insularis.

So far, it has been found that UV absorbance of organosolv lignin treated for 10 days by F. insularis tended to decrease. This is thought to be due to high activities of lignolytic enzymes secreted from F. insularis. The decrease in the absorbance of lignin after incubation with fungus has been considered as an indication of the extent of lignin biodegradation. In the next phase of the project, the changes of chemical functional groups in organosolv lignin by F. insularis will be analyzed using FT-IR and ¹³C-NMR to identify chemical structures and carbon types of the lignin. The changes in ether bond and phenolic hydroxyl groups also will be analyzed by the nitrobenzene oxidation method and aminolysis reaction, respectively. Consequently, this study is expected to help to understand the changes of structural properties of organosolv lignin by white rot fungus.