Potato dextrose agar pda

Fruits samples were processed for the isolation of fungal causal agents. Causal fungi were isolated from lesions using a single conidial isolation on 1.0% water agar containing 0.5 mg/l streptomycin under a stereo microscope according to the method described by Choi et al. [29 ]. The isolated plates were incubated at 25 °C in darkness for 24–48 h, and the germinated conidia were then transferred onto potato dextrose agar (PDA; Conda, Madrid, Spain) containing 0.5 mg/L streptomycin. Pure fungal isolates were deposited in the culture collection of the Sustainable Development of Biological Resources, Faculty of Science, Chiang Mai University (SDBR-CMU), Chiang Mai Province, Thailand.

The black fungus Exophiala mesophila strain IRTA-M2-F10 (culture collection at the Institute of Agrifood Research and Technology, Spain) isolated previously from biodeteriorated glued ceramics was selected the source of fungal melanin because of its tolerance to heavy metals and easy cultivation under laboratory conditions (Medina-Armijo et al., 2024 (link)). Active cultures of this fungus were routinely maintained on potato dextrose agar (PDA; Condalab, Spain) incubated at 25°C in the darkness. Ten agar pre-grown fungal colonies of 5 to 7 mm in diameter (after about three weeks of incubation) were transferred into 250 mL of liquid medium that contained macronutrients (4.5 g KH₂PO₄, 0.5 g K₂HPO₄, 2.0 g NH₄Cl, and 0.1 mg MgSO₄ 7H₂O per liter), 2 mL of a stock solution of micronutrients (120 mg FeCl₃, 50 mg H₃BO₃, 10 mg CuSO₄ 5H₂O, 10 mg KI, 45 mg MnSO₄ · H₂O, 20 mg Na₂MoO₄ H₂O, 75 mg ZnSO₄ H₂O, 50 mg CoCl₂ 6H₂O, 20 mg AlK(SO₄)₂ 12H₂O, 13.25 g CaCl₂ H₂O, and 10 g NaCl, per liter), and yeast extract (4 g L⁻¹) as the carbon and energy source. The incubation of this liquid culture was performed under dark conditions at 25°C on a horizontal shaker (80 rpm) and was maintained for three weeks. Fungal biomass was then harvested by centrifugation (18 g for 20 min) and used immediately for melanin extraction.

The pure mycelia of four trimitic hyphal species (Ganoderma fornicatum CMU-NK0524; GF, Ganoderma williamsianum CMU-NK0540; GW, Lentinus sajor-caju CMU-NK0427; LS, and Trametes coccinea CMU-AM005; TC) along with one monomitic hyphal species (Schizophyllum commune CMU-S01; SC) were derived from the culture collection of the Research Center of Microbial Diversity and Sustainable Utilization (RCMU), and the Sustainable Development of Biological Resources Laboratory (SDBR-CMU), Faculty of Science, Chiang Mai University, Thailand. These species have been previously studied and have been reported to show potential for producing MBCs with several great properties, unique characteristics, and beautiful colors without the use of added pigments [11 (link),16 (link)]. All fungal species were grown for 7 days at 30 °C on potato dextrose agar (PDA; Conda, Madrid, Spain).