Biotechnological treatment of oil mill waste-water to produce high value-added mycelial products.

Several trials with Pleurotus pulmonarius mushroom were carried out in liquid state cultures, in synthetic media containing commercial glycose and olive mill wastewater (OMW) with phenolics concentration adjusted to 10% and 30% v/v. Results demonstrated that at the end of fermentation period the phenolic content reduction was very high (93-95%), as well as substrate decoloration, with values ranging from 70% to 85% (medium containing 10 and 30% v/v phenolic compounds respectively), indicating the great capability of Pleurotus strains for OMW detoxification. Moreover, the highest phenolic concentration (30% v/v) affected positively biomass and intra-cellular polysaccharide (IP) production, reaching 30.61 g/L and 4.30 g/L, respectively. On the other hand, although lower values of biomass and IP in absolute values were synthesized in the medium with 10% v/v phenolic compounds (22.66 and 3.92 g/L respectively), the amount of IP in relative values was as high as 20 w/w. The maximum anti-oxidant activity (expressed as total phenolic compounds) of 0.4 g/L was also determined in P. pulmonarius biomass produced in the medium with 10% v/v phenolics. In conclusion, the examined mushroom species could be used with great success as a mean of biological treatment of OMWs with simultaneous production of high nutritional value products (biomass, polysaccharides, phenolic compounds).