PRODUCTION OF RIBITOL BY ALGINATE-IMMOBILIZED CELLS OF THE LICHEN CLADONIA-VERTICILLARIS

Cells of the lichen Cladonia verticillaris have been immobilized in ca lcium alginate and incubated for 15 days in light on different concent rations of sodium bicarbonate in order to produce lichen polyols. Suga rs and polyols secreted to the medium were extracted and analyzed by H PLC. Production and secretion of both ribitol and glucose were very hi gh by entrapped cells incubated on 10 mM sodium bicarbonate but the re placement of calcium by sodium in the alginate matrix produced the dis organization of the immobilized system in a period no longer than 5 da ys. However, incubation of the entrapped cells on 1 mM sodium bicarbon ate preserved the structure of the innert matrix altough only ribitol was produced and secreted to the medium. Entrapment in sodium alginate maintained cell vitality although chloroplast disorganization of the phycobiont became evident. Moreover, contact between myco- and phycobi ont has also been altered during immobilization since algal ribitol wa s not converted into mannitol by the fungal partner.