title: Enzymatic hydrolysis of olive wastewater for hydroxytyrosol enrichment.
abstract: Aspergillus niger broth culture on wheat bran was assessed for olive wastewater (OW) hydrolysis in order to release hydroxytyrosol (HT). The enzyme profiles of this culture broth gave essentially (IU/L): 3000 β-glucosidase and 100 esterase. Hydrolysis activity of A. niger enzyme preparation was evaluated by using three substrates: raw OW, phenolic fraction extracted from OW by ethyl acetate and its corresponding exhausted fraction. Large amounts of free simple phenolics were released from exhausted fraction and raw OW after enzymatic treatment. HPLC analyses show that HT was the main phenolic compound. One step of ethyl acetate extraction of hydrolysed OW allowed the recovery of 0.8 g of HT per litre of OW. The antioxidant activity of extracts from OW and exhausted fraction, measured by DPPH method, was drastically enhanced after hydrolysis treatment. This study demonstrates that hydrolysed OW is a potential source of bioactive phenolic compounds with promising applications in food and pharmaceutical industries.
authors.affiliation: Laboratoire des Bioprocédés Environnementaux, Pôle d'Excellence Régional (PER, AUF), Centre de Biotechnologie de Sfax, Université de Sfax, B.P. 1117, 3018 Sfax, Tunisia. sonia.khoufi@cbs.rnrt.tn
authors.forename: Sonia
authors.initials: S
authors.lastname: Khoufi
authors.forename: Manel
authors.initials: M
authors.lastname: Hamza
authors.forename: Sami
authors.initials: S
authors.lastname: Sayadi
mesh_terms: D000085:Acetates; D001234:Aspergillus niger / Q000378:metabolism*; D002681:China; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006868:Hydrolysis; D031658:Olea / Q000737:chemistry*; D010636:Phenols / Q000032:analysis; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000378:metabolism; D012987:Soil; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000085:Acetates; D010636:Phenols; D012987:Soil; C005975:3,4-dihydroxyphenylethanol; C007650:ethyl acetate; D010626:Phenylethyl Alcohol