MODELING OF THE BIOSYNTHESIS OF LIGNIN AS A PROCESS OF ENZYMATIC DEHYDROPOLYMERIZATION MONOLIGNOLS

Abstract

The results of theoretical modeling of lignin biosynthesis in the system of peroxidase-hydrogen peroxide-monolignol are presented. The process under study is presented as a sequence of enzymatic and chemical reactions occurring in an open system. The growth of the lignin molecule is due to successive stages of the formation of phenoxyl radicals of different generation numbers and acts of recombination of these radicals. The mathematical model of the process in the form of a system of 14 differential equations is proposed for the first time. For the numerical solution of the system, the eighth order Runge-Kutta-Fehlberg method with an automatic integration step was applied. The results of numerical integration are presented, which indicate a significant dependence of the process dynamics on the initial conditions. Various modes of the process, including oscillatory modes, are found. Features of the system dynamics are due to the choice of the initial concentration of monolignol, hydrogen peroxide and the enzyme, as well as the nonlinearity of differential equations and the presence of feedbacks. The results of numerical experiments within the framework of the first proposed mathematical concept on dehydropolymerization of monolignols allow us to give a theoretical justification of the phenomena that are currently treated as the processes of dynamic self-organization in the biosynthesis of this polymer.