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Licensed Unlicensed Requires Authentication Published by De Gruyter February 9, 2011

Two-step hydrolysis of nipa (Nypa fruticans) frond as treated by semi-flow hot-compressed water

Natthanon Phaiboonsilpa, Pramila Tamunaidu and Shiro Saka
From the journal

Abstract

Two-step hydrolysis of nipa (Nypa fruticans) frond, one of the monocotyledonous angiosperms, was studied in a semi-flow hot-compressed water treatment at 230°C/10 MPa/15 min (first stage) and 270°C/10 MPa/30 min (second stage). In the first stage, hemicelluloses such as O-acetyl-4-O-methylglucuronoarabinoxylan and pectin and para-crystalline cellulose were selectively hydrolyzed, as well as lignin, which was partially decomposed. In the second stage, hydrolysis of crystalline cellulose and some additional decomposition of lignin were observed. In addition, inorganic constituents and free sugars, composed mainly of glucose, fructose, and sucrose, were recovered in cold water (20°C/10 MPa/30 min) prior to these 2 stages. In total, 97.3% of oven-dried nipa frond sample could be solubilized into cold and hot-compressed water. The degradation products in the water-soluble portion were primarily recovered as various saccharides (hydrolyzed moieties of the polyoses), which were later dehydrated, fragmented and isomerized partly. The residual (2.7%) is composed mainly of lignin associated with 0.4% of Si. A decomposition pathway is proposed for O-acetyl-4-O-methylglucuronoarabinoxylan as the major hemicellulose based on its various hydrolyzed products.


Corresponding author. Department of Socio-Environmental Energy Science, Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan

Received: 2010-9-1
Accepted: 2010-12-28
Published Online: 2011-02-09
Published Online: 2011-02-9
Published in Print: 2011-08-01

©2011 by Walter de Gruyter Berlin Boston

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