Fungal Biodegradation of Tannins from Creosote Bush (Larrea tridentata) and Tar Bush (Fluorensia cernua) for Gallic and Ellagic Acid Production

Abstract

In the present work, the production of two potent antioxidants, gallic and ellagic acids, has been studied using solid-state fermentation (SSF) of tannin-rich aqueous plant extracts impregnated in polyurethane foam. Extracts from creosote and tar bush were ino-culated with Aspergillus niger PSH spores and impregnated in the polyurethane support.The kinetics of the fermentation was monitored every 24 h. The maximum biodegradation of hydrolysable and condensed tannins was, respectively, 16 and 42 % in creosote bush, and 40 and 83 % in tar bush. The maximal productions of gallic and ellagic acid (152 and177 %, respectively) were reached with aqueous extracts of creosote bush. Tar bush extracts inoculated with A. niger PSH spores produced only gallic acid (92 %), while ellagic acid was not recovered after the fermentation process. Results demonstrated the potential use of these plants as a source for the production of antioxidants