| Summary: | Fermentation in solid state culture (SSC) has been the focus of increasing interest because of its potential for industrial applications. In previous studies SSC of pomegranate wastes by <i>Aspergillus niger</i> has been extensively developed and optimized for the recovery of ellagic acid (EA), a high value bioactive. In this study we comparatively investigated the SSC of powdered pomegranate husks by <i>A. niger</i> and <i>Saccharomyces cerevisiae</i> and evaluated the recovery yields of EA by an ultrasound and microwave-assisted 7:3 water/ethanol extraction. Surprisingly enough, the yields obtained by <i>S. cerevisiae</i> fermentation (4% <i>w</i>/<i>w</i>) were found 5-fold higher than those of the <i>A. niger</i> fermented material, with a 10-fold increase with respect to the unfermented material. The EA origin was traced by HPLC analysis that showed a significant decrease in the levels of punicalagin isomers and granatin B and formation of punicalin following fermentation. Other extraction conditions that could warrant a complete solubilization of EA were evaluated. Using a 1:100 solid to solvent ratio and DMSO as the solvent, EA was obtained in 4% yields from <i>S. cerevisiae</i> fermented husks at a high purity degree. Hydrolytic treatment of <i>S. cerevisiae</i> fermented pomegranate husks afforded a material freed of the polysaccharides components that gave recovery yields of EA up to 12% <i>w</i>/<i>w</i>.
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