ENZYMATIC CONVERSION OF ANTHRAQUINONE PIG MENT ORIGINATED FROM MADDERAND PRODUCT EXTRACTION IN BATCH REACTION

Enzymatic hydrolyses of anthraquinone glycosides (Alizarin-2-o-primeve roside (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-gluc osidase showed the highest hydrolytic activity and reaction selectivit y for Al-P. Hydrolyses of anthraquinone glycosides were carried out in a batch operation by using the beta-glucosidase immobilized by covale nt linkage to fine powders of TiO2, and it was found that the formed a lizarin exerted an inhibitory effect on the enzyme reaction. Separatio n and recovery of alizarin in a hexane phase were performed by combini ng solvent extraction with enzyme reaction, reducing the inhibitory ef fect on the reaction caused by alizarin. Taking into account the parti tion equilibrium between the aqueous and hexane phases, time profiles of the formation and extraction processes of alizarin were successfull y expressed in a batch operation by a Michaelis-Menten equation consid ering the product inhibition.