1996 Volume 22 Issue 4 Pages 891-897
Enzymatic hydrolyses of anthraquinone glycosides (Alizarin-2-ο-primeveroside (Al-P) and Lucidin-3-ο-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 β-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 β-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.
