Modelling of the biotransformation from geraniol to nerol by freely suspended and immobilised grape (Vitis vinifera) cells

Abstract

Abstract Plant cell suspensions of Gamay grape cells ( Vitis vinifera L. cv. Gamay Freaux) were immobilized in calcium alginate beads. Both freely suspended and immobilised cells were able to biotransform geraniol into nerol in a biphasic system based upon the culture medium and Miglyol 812 N. A model was developed to describe the reaction kinetics. The model assumes that geraniol is transformed into nerol and this into geraniol. In addition both geraniol and nerol can be metabolised to other compounds. Michaelis-Menten kinetics was proposed to describe every interconversion. Once first estimates were assigned to the defined parameters (maximum specific rates of monotherpene production and degradation and saturation constants) the numeric integration of the whole set of differential equations was feasible. The resultant parameter values were useful to predict the behaviour of the immobilised system. Immobilisation did not affect, in a significant manner, the rate of interconversion. The model also gave a satisfactory representation of the reaction kinetics when Monastrell grape cell suspensions ( Vitis vinifera L. cv. Monastrell) were used instead of the Gamay ones.