alexa Enzymatic grafting of hexyloxyphenol onto chitosan to alter surface and rheological properties.
Chemical Engineering

Chemical Engineering

Journal of Chemical Engineering & Process Technology

Author(s): Chen T, Kumar G, Harris MT, Smith PJ, Payne GF

Abstract Share this page

Abstract An enzymatic method to graft hexyloxyphenol onto the biopolymer chitosan was studied. The method employs tyrosinase to convert the phenol into a reactive o-quinone, which undergoes subsequent nonenzymatic reaction with chitosan. Reactions were conducted under heterogeneous conditions using chitosan films and also under homogeneous conditions using aqueous methanolic mixtures capable of dissolving both hexyloxyphenol and chitosan. Tyrosinase was shown to catalyze the oxidation of hexyloxyphenol in such aqueous methanolic solutions. Chemical evidence for covalent grafting onto chitosan was provided by three independent spectroscopic approaches. Specifically, enzymatic modification resulted in (1) the appearance of broad absorbance in the 350-nm region of the UV/vis spectra for chitosan films; (2) changes in the NH bending and stretching regions of chitosan's IR spectra; and (3) a base-soluble material with (1)H-NMR signals characteristic of both chitosan and the alkyl groups of hexyloxyphenol. Hexyloxyphenol modification resulted in dramatic changes in chitosan's functional properties. On the basis of contact angle measurements, heterogeneous modification of a chitosan film yielded a hydrophobic surface. Homogeneously modified chitosan offered rheological properties characteristic of associating water-soluble polymers. Copyright 2000 John Wiley & Sons, Inc.
This article was published in Biotechnol Bioeng and referenced in Journal of Chemical Engineering & Process Technology

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords