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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Cotton Structure and Quality Research » Research » Publications at this Location » Publication #309604
Title: Chromosphores in cellulosics, XI: isoloation and identification of residual chromophores from bacterial cellulose

Author
item ROSENAU, THOMAS - University Of Natural Resources & Applied Life Sciences - Austria
item POTTHAST, ANTJE - University Of Natural Resources & Applied Life Sciences - Austria
item KRAINZ, KARIN - University Of Natural Resources & Applied Life Sciences - Austria
item HETTEGGER, HUBERT - University Of Natural Resources & Applied Life Sciences - Austria
item HENNIGES, UTE - University Of Natural Resources & Applied Life Sciences - Austria
item YONEDA, YUKO - University Of Natural Resources & Applied Life Sciences - Austria
item ROHRER, CHRISTIAN - Lohmann & Rauschler Gmbh & Co Kg
item FRENCH, ALFRED - Retired ARS Employee

Submitted to: Cellulose
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2014
Publication Date: 8/20/2014
Citation: Rosenau, T., Potthast, A., Krainz, K., Hettegger, H., Henniges, U., Yoneda, Y., Rohrer, C., French, A.D. 2014. Chromosphores in cellulosics, XI: isoloation and identification of residual chromophores from bacterial cellulose. Cellulose. 21:2271-2283.

Interpretive Summary: One of the problems with cotton textiles and other items made from cellulose such as paper is that they turn yellow with age and deteriorate with age. Of course, it is likely that the color change is associated with the loss of strength, so it has been of interest to study the molecules that cause the color to appear. These molecules, or chromophores, are thought to result from oxidation with the cellulose, generally, and not from any other material. Another type of cellulose is made by bacteria, and it was of interest to learn whether aged bacterial cellulose would have the same compounds in it that give color to other forms of cellulose. The answer was yes, that BC does make the benzoquinone molecule and related compounds, just like cellulose from other sources. In addition, it was found that if the bacterial cellulose was not sufficiently purified of the protein associated with its biosynthesis, then that protein and the carbohydrate can react to form other colored compounds as the cellulose ages.

Technical Abstract: In the present work, bacterial cellulose (BC) was analyzed for its chromophore content with the chromophore release and identification (CRI) method. In aged BC, seven chromophores were unambiguously identified, despite their very low (ppb) presence. The compounds contain 2-hydroxy-[1,4]benzoquinone, 2-hydroxyacetophenone and 5,8-dihydroxy-naphthoquinone moieties. These three classes of key chromophores had also been found in other celluloses such as bleached pulp, fiber and derivatives. The detection of chromophores in lignin-free BC confirms that the chromophores are formed from oxidized and degraded carbohydrate material rather than lignin fragments. Samples that were insufficiently purified before the aging step also yielded three N-heterocyclic compounds. They originated from tryptophan moieties in residual adhering protein and protein degradation products. N-Heteropentacycles 9 and 10 showed strong adsorption onto cellulosic surfaces, and that adsorption aided oxidation of cyclohexadiene derivative 9 into the corresponding aromatic and intensely yellow system 10, consistent with the strain-induced bond localization theory. In purified fresh BC, no chromophores were detectable by the CRI method. The present contribution is the first report on defined chromophoric structures isolated from BC.