Cultural and Physiological Studies of Ganoderma neo-japonicum and G. zonatum

[[abstract]]Ganoderma neo-japonicum is found in Mainland China, Japan and Taiwan and grows saprotrophically on dead hardwoods or bamboos. G. zonatum is distributed only in the States of Georgia and Florida of the United States and its substrate is known only on palms. Pure cultures of G. neo-japonicum and G. zonatum were used for cultural and physiological studies. The mycelial growth characteristics of G. neo-japonicum and G. zonatum were observed as the white color on the mycelial mat’s surface, brown color on the reverse side, clamped generative hyphae and the appearance of swelling cells in culture. The positive reaction for extracellular oxidases which included laccase and peroxidase, but negative for tyrosinase, indicated both G. neo-japonicum and G. zonatum belong to white rotting fungi, and showed that they can utilize lignin, cellulose and hemicellulose of wood. The results of physiological tests were shown as follows: 1.Optimum temperature for the mycelial growth of G. neo-japonicum was at 24~28℃ on both MEA and PDA, while G. zonatum was at 32℃ both on MEA and PDA. 2.Optimum pH was 4.6 for the mycelial growth of G. zonatum. 3.Glucose concentration at 40~80 g/L was the optimal condition for the mycelial growth of G. neo-japonicum and G. zonatum. Increasing glucose concentration neither increased nor decreased the mycelia growth rate of G. neo-japonicum, but decreased the mycelial growth rate of G. zonatum. 4.Starch was the best carbon source for both mycelial growth of G. neo-japonicum and G. zonatum. 5.Optimal nitrogen concentration of ammonium nitrate (NH4NO3) was at 0.02 N for the mycelial growth of G. neo-japonicum, and 0.04 N for G. zonatum. The mycelial growth of G. zonatum was in proportion to the concentration of L-Asparagine (organic nitrogen form), but was not for G. neo-japonicum.