par David, Christiane 
;Daro, Arlette ;Szalai, E.;Atarhouch, Touriya ;Mergeay, Maximilien
Référence European Polymer Journal, 32, 6, page (669-679)
Publication Publié, 1996-06
;Daro, Arlette ;Szalai, E.;Atarhouch, Touriya ;Mergeay, Maximilien Référence European Polymer Journal, 32, 6, page (669-679)
Publication Publié, 1996-06
Article révisé par les pairs
| Résumé : | The formation of polymeric pigments using bacteria was investigated to produce new polymers. Polymeric pigments are formed from mutant strains of Alcaligenes eutrophus which are not able to open the aromatic ring (tyu-) but transform tyrosine into p-hydroxyphenylacetic acid. This compound is then hydroxylated into homogentisic acid which undergoes oxidative coupling into polymeric pigments. Another carbon source is required to allow bacterial growth. The rate of disappearance of the initial product (either tyrosine or p-hydroxyphenylacetic acid) and the rate of formation and disappearance of intermediates were studied by ultraviolet (UV) absorption spectroscopy and high-performance liquid chromatography (HPLC). Pigment formation was monitored by gel permeation chromatography (GPC). The pigment was isolated and characterized by UV and infrared (IR) absorption spectroscopy, nuclear magnetic resonance (NMR) and elemental analysis. It was shown to have a complex structure involving aromatic and aliphatic saturated and unsaturated structures. Nitrogen is incorporated by condensation with amino acids and other nitrogen-containing molecules excreted by the bacteria. For comparative purposes, chemical oxidative coupling of homogentisic acid in the absence of bacteria was performed at pH 8.5 and 11.5 in the presence of oxygen. A badly defined but different mixed aliphatic-aromatic structure was isolated. The role of the bacteria in the different steps of transformation of the initial product is discussed. Copyright © 1996 Elsevier Science Ltd. |
