Optimization of Nutritional Requirements for the Mycelial Growth of Trametes cubensis and Lentinus velutinus

Trametes cubensis and Lentinus velutinus are wood-rotting macrofungi belonging to the order Polyporales under the family Polyporaceae. These mushrooms are medicinally important and are important decomposers because of the presence of wood-degrading enzymes. This study evaluated the nutrient requirements for the optimum mycelial growth of the two mushroom species in a semi-solid medium. Results revealed that the tested nutrients significantly affected the mycelial growth rate and density of T. cubensis and L. velutinus. T. cubensis exhibited the widest mycelial diameter and very thick mycelial density when cultivated on a medium with 10:1, 5:1 and 2:1 ratios of fructose and malt extract as the primary carbon and nitrogen sources, respectively. The addition of mineral salts, including MgSO4, K2HPO4, NaCl, FeSO4, KH2PO4 and CuSO4, recorded fast mycelial growth, but only MgSO4 produced the very thick mycelial density of T. cubensis. Acetic acid, the five tested vitamins, and the four phytohormones showed favorable mycelial growth of T. cubensis. On the other hand, the 10:1 glucose-to-yeast extract ratio was the best carbon and nitrogen source for L. velutinus. Lactic acid, vitamins such as ascorbate, thiamine, folate, and pyridoxine, and the phytohormone 6-benzylaminopurine promoted the efficient mycelial growth L. velutinus. Taking the data together, both mushrooms require unique culture medium composition for their luxuriant growth, which is necessary for the sustainable production and utilization of these mushrooms in various applications.