Enhancing rice bran oil yield through solid state fermentation pretreatment with fungi

Abstract

Indonesia produces a huge amount of rice bran on an annual basis, but not yet converted into valuable products, such as rice bran oil (RBO). RBO is generally produced by solid-liquid extraction through the contact between rice bran and solvents. However, this method produces a low yield of RBO, ranging from 8-19%. This study was conducted to increase the yield of oil from the bran through solid-state fermentation with fungi, Aspergillus niger and Saccharomyces cerevisiae. The highest bran oil yield extracted from the fermented substrate by Aspergillus niger for five days was 14.20%, while the one fermented by Saccharomyces cerevisiae was 24.15% at the incubation time of four days, respectively. The quality of rice bran oil treated with Aspergillus niger is close to that of a commercial product. Although quantitatively, the oil obtained from bran fermented by Saccharomyces cerevisiae is much higher, a further refining process is required to produce a clear edible oil. Compared to those of conventional extraction methods, the pretreatment of rice bran by solid-state fermentation increases the oil yield up to three times compared to the control.