Remediation of olive mill wastewater (OMW) is an important issue associated with olive-oil manufacturing, a widespread activity in the Mediterranean area. This high organic loading effluent contains water, organic acids, high-molecular-weight polyphenols such as tannins, antocyanins and catechins, which are considered to be responsible for its brownish black colour and toxic properties. The composition of OMWs is highly variable with respect to each individual component, depending on the process conditions and on the agricultural specificities. In this work, the ability of a “white-rot” fungus, Bjerkandera paranensis, to use undiluted OMW from a two phase process mill (COD = 11.1 gl-1; Phenol Content = 3.9 gl-1; ColourAbs395nm = 7.8) as a substrate was studied. The biodegradation potential of B. paranensis was assessed monitoring several physico-chemical parameters. A chronic ecotoxicity test (Vibrio fisheri growth inhibition test) was carried out to follow the detoxification ability of this fungus. In work, the results demonstrate that OMW was a suitable medium for cultivation of B. paranensis, with corresponding changes in the physico-chemical properties of the OMW. The results showed that B. paranensis removed 93% phenols and 54% COD from the culture medium within 21 days of treatment. In addition, the IC50s values obtained for the different treated samples showed a significant decrease in the effluent chronic toxicity to V. fischeri when the OMW pH was adjusted to 6.0 prior to the treatment (71.8 %), highlighting the OMW detoxification capacity of B. paranensi
