An enhanced, xylose-utilizing strain of Rhizopus arrhizus was successfully developed via modification using media with increasing concentrations of xylose. Xylose, a relatively cheap monosugar that can be easily obtained from corncobs, rice straw, and vinasse, was the sole carbon source used for both the seed culture phase and the fermentation process. After modification, this newly improved strain showed tremendous industrial potential for fumaric acid production using xylose. The fumaric acid production increased to 28.48 g/L (parental strain was 13.23 g/L) at 8% initial xylose, a carbon:nitrogen ratio of 200, and a residence time of 7 days. The volumetric productivity was 169.52 mg/L (78.75 mg/L) per hour.