Fumaric acid is a dicarboxylic acid used extensively in resins, food acidulants, and other applications including oil field fluids, esters etc. Some strains of Rhizopus oryzae, which is a filamentous fungus, can produce fumaric acid from sugars under aerobic conditions but the fumarate yield is relatively low due to the co-production of ethanol and other fermentation byproducts. In this work, metabolic engineering technique is applied to optimize the fermentation for enhanced fumaric acid production. More fumaric acid can be produced from sugars when the alcohol dehydrogenase and pyruvate decarboxylase genes are inactivated. Fumaric acid production can also be increased by overexpressing the enzymes, such as fumarase and pyruvate carboxylase, in the fumaric acid production pathway. These genes were obtained from Rhizopus oryzae genome by using PCR, and then cloned into the fungal cells by biolistic transformation. The effects of transformation on the mutants and fumaric acid fermentation kinetics were studied and will be reported in this paper.