New biotechnological methods for producing therapeutic compounds (Usnic, Stictic and Norstictic Acids) by cell immobilization of the lichen Cladonia substellata Vainio

Abstract

The aim of this paper is related to the modifications of the most usual method for producing USN and others bioactive compounds by the lichen Cladonia substellata to rationalize ecologically the provision of those at large scale. Different cell immobilization systems were assayed, using NaOAc as biosynthetic precursor at different concentrations. The introduced new systems to the most usual, consisting of the static incubation of immobilizates, were bioreactors in rotary movement and in continuous flow of precursor. They clearly enhance the production of USN. In addition, the kind of immobilization system can vary the content of produced metabolites. The occurrence of reduced USN and the occurrence of both NTI and STI acids in the cell washes were correlated. In this way, the modification of immobilization technique leads to highest production of these metabolites, and to a better use of the precursor, but it does not show any significant influence on the production of accessory and/or degraded compounds of the chemical species. On the basis of our results, USN and other compounds from C. substellata were produced in substantial amounts by kaolinite-immobilized continuous flow system and, in a general way, at a concentration of 10.0 mM, using NaOAc as precursor.