2.3. Estimation of OMW’s physicochemical parameters and phytotoxicity
Samples’ pH was measured by a Scott Geräte TR156 pH-meter. Color was determined by measuring samples absorbance at 525 nm, whereas total phenolics were estimated by the Folin–Ciocalteu method against a syringic agenerase calibration curve and soluble COD (Chemical Oxygen Demand) was analyzed as previously described by Clesceri et al. (1998). Phytotoxicity was estimated by measuring the seed germination index (GI) of cress (Lepidium sativum): 25 cress seeds were placed onto a filter paper, moistened by the biotreated OMW (or by water for the control), incubated for 3 days in the dark, and then their germination percentage was calculated ( Ntougias et al., 2012).
2.4. Determination of enzyme activities
2.5. Experimental design
For evaluating the potential of various wood-rot fungi in detoxifying OMW, 49 strains were grown for 5 weeks in a vascular parenchyma medium consisting of 50 ml 25% (v/v) OMW sampled during the first year. Fungal biomass, total phenolics, COD, decolorization, phytotoxicity (as expressed by cress seeds germination index), laccase, and Mn-dependent and -independent peroxidase activities were determined at the end of the incubation period.