Cell growth and pigment production in suspension cultures of a mycobiont isolated from the lichen Cladonia cristaiella

Abstract

This is the first study on the factors that affect cell growth and the production of secondary metabolites of a lichen mycobiont in liquid culture. An ascospore-derived strain of Cladonia cristatella mycobiont accumulated and excreted red pigments into a liquid medium. Growth of the mycobiont was increased by using liquid Lilly–Barnett medium containing 16% (w/v) sucrose as a carbon source, 0.2% (w/v) L-glutamine as a nitrogen source, and 0.2% (w/v) polypeptone, adjusting pH to 5.0 before autoclaving, and incubating cultures at 20 °C. Pigment production by the mycobiont was increased by using liquid Lilly–Barnett medium containing 4% (w/v) sucrose as a carbon source, 0.2% (w/v) L-asparagine as a nitrogen source, and 0.2% (w/v) malt extract, adjusting pH to 5.0 before autoclaving and incubating cultures at 20 °C. All acetone extracts under any cultural conditions yielded similar HPLC chromatograms. We proved no relationship between cell growth and secondary metabolism based on the nutritional factors in the cultured C. cristatella mycobiont. Key words: lichen, suspension culture, Cladonia cristatella mycobiont, red pigment, production, and growth factor.