Formation of self-organized periodic patterns around yeasts secreting a precursor of a red pigment.

Formation of self-organized regular patterns (Liesegang patterns) due to reaction-diffusion process in the gel medium and related to vital activity of yeasts is presented. Two different yeast strains (Candida pulcherrima and non-Candida pulcherrima) possess a common characteristic feature to secrete a precursor which in the presence of iron(III) ions forms an insoluble red pigment. During yeast cultivation onto solid agar media, periodic spontaneous distinctly spaced red-colored patterns around the yeasts can are formed if the concentration of elemental iron in the growth media is in the range 4-12mg/L. By changing the composition yeast growth media (YEPD or minimal), growth time and temperature, the mode of yeast inoculation, a variety of red-pigmented patterns around live and proliferating yeasts can be obtained.