Ellagic Acid Production from Biodegradation of Creosote Bush Ellagitannins by Aspergillus niger in Solid State Culture

The ability of Aspergillus niger GH1 in converting creosote bush ellagitannins into ellagic acid (EA) was evaluated in solid state culture. Creosote bush leaves were used to extract the ellagitannins fraction, which was impregnated in polyurethane foam used as support of solid state culture. Ellagitannins content, EA accumulation, and the related enzymatic activities were evaluated. A. niger GH1 was able to completely degrade creosote bush ellagitannins with an EA yield of 23.1% at 36 h of culture. The ability to degrade creosote bush ellagitannins exhibited by A. niger GH1 was clearly associated to an ellagitannin-hydrolysing enzyme with a maximum activity of 43 U/l, while that ability was not associated to tannase activity that was detected in the culture extract. This study demonstrated the great ability of A. niger GH1 to hydrolyze ellagitannins and the potential of solid state culture to produce the antioxidant EA by degradation of creosote bush ellagitannins.