Production of Fumaric Acid by Rhizopus oryzae in Simultaneous Saccharification and Fermentation using Xylo-Oligosaccharides Manufacturing Waste Residue

Production of fumaric acid from xylo-oligosaccharides manufacturing waste residue (XOR) by Rhizopus oryzae CICC 40351 was investigated in a simultaneous saccharification and fermentation (SSF) process. The fermentation conditions for SSF were optimized by an orthogonal design method to maximize the fumaric acid concentration. The highest fumaric acid concentration (12.54 g/L) was reached with a substrate loading of 5% (w/v) XOR in the SSF process at 38 °C. The fumaric acid concentration of the SSF process was 1.8 times greater than that of the separate hydrolysis and fermentation (SHF) process under the same conditions. In addition, the SSF process yielded 0.34 g/g of glucose, whereas the SHF process yielded only 0.20 g/g of glucose. The results indicated that the SSF process notably improved the production of fumaric acid from lignocellulose by R. oryzae.