KAGAKU KOGAKU RONBUNSHU, Vol.22, No.4, 891-897, 1996
Enzymatic conversion of anthraquinone pigment originated from madder and product extraction in batch reaction
Enzymatic hydrolyses of anthraquinone glycosides (Alizarin-2-o-primeveroside (Al-P) and Lucidin-3-o-primeveroside (Lu-P)) from madder plant were examined for the formation and separation of the useful pigment, alizarin. Among enzymes tested in this study, almond-derived beta-glucosidase showed the highest hydrolytic activity and reaction selectivity for Al-P. Hydrolyses of anthraquinone glycosides were carried out in a batch operation by using the beta-glucosidase immobilized by covalent linkage to fine powders of TiO2, and it was found that the formed alizarin exerted an inhibitory effect on the enzyme reaction. Separation and recovery of alizarin in a hexane phase were performed by combining solvent extraction with enzyme reaction, reducing the inhibitory effect on the reaction caused by alizarin. Taking into account the partition equilibrium between the aqueous and hexane phases, time profiles of the formation and extraction processes of alizarin were successfully expressed in a batch operation by a Michaelis-Menten equation considering the product inhibition.
Keywords:RUBIA-TINCTORUM L;HYDROXYANTHRAQUINONES