Mycelial pellet formation by Rhizopus oryzae ATCC 20344

Factors in a cultivation medium affecting fungal growth morphology and fuma ric acid production by Rhizopus ouyzae ATCC 20344 were investigated. These factors included the initial pH value and trace metals such as zinc, magnes ium, iron, and manganese in the cultivation medium. It was found that a sig nificant change in the growth morphology of X. ouyzae ATCC 20344 occurs whe n the initial pH value is varied. A lower initial pH value in the cultivati on medium was inhibitory to fungal growth, and fast growth in the cultivati on medium at a higher initial pH value promoted the formation of large pell ets or filamentous forms. Trace metals in the cultivation media also had si gnificant effects on pellet formation and fumaric acid fermentation.