Post-print version submitted to Waste and Biomass Valorization Suggested Citation M.Varman and S. Saka. "A Comparative Study of Oil Palm and Japanese Beech on Their Fractionation and Characterization as Treated by Supercritical Water" Waste and Biomass Valorization

13 Supercritical water treatment (380ºC/100MPa/8s) was applied to extractives-14 free oil palm trunk and sapwood portion of Japanese beech and their fractionated 15 products were comparatively characterized, for water-soluble portion and water-16 insoluble portion composed of methanol-soluble portion and methanol-insoluble 17 residue. As a result, the water-soluble portion was determined to be composed of 18 carbohydrate-derived products such as organic acids, sugar decomposed products and 19 lignin-derived products, etc. for both species. The oil palm, however, shows higher 20 yield of organic acids and lignin-derived products compared to Japanese beech. The 21 methanol-soluble portion was, on the other hand, mainly composed of lignin-derived 22 products, and in oil palm, these lignin-derived products consisted of both syringyl and 23 guaiacyl-type similar to Japanese beech. The methanol-insoluble residue, was also 24 mainly composed of lignin to be 99.2% in its content in the oil palm, compared to 25 *Manuscript Japanese beech 93.7%. Moreover, the phenolic hydroxyl content determined by 1 aminolysis method was higher in oil palm (36.5 PhOH/100C 9) compared to Japanese 2 beech (16.9 PhOH/100C 9). Furthermore, an alkaline nitrobenzene oxidation analysis 3 indicated that, the methanol-insoluble residue of the oil palm was less in oxidation 4 products whereas in Japanese beech nitrobenzene oxidation products completely 5 diminished. These lines of evidence suggest that methanol-insoluble residue is 6 composed of lignin with more condensed-type of linkages with high phenolic 7 hydroxyl groups. In addition, the water-soluble portion could be utilized for organic 8 acid production, whereas the methanol-soluble portion and its insoluble residue for 9 phenolic chemical production.