Detoxification of Olive Mill Wastewater and Bioconversion of Olive Crop Residues into High Value Added Biomass by the Choice Edible Mushroom Hericium erinaceus
Environmentally acceptable disposal of olive cultivation residues (e.g. olive prunings; olive pruning residues (OLPR) and olive mill wastes is of paramount importance since they are generated in huge quantities within a short time. Moreover, olive mill wastewater (OMW) or sludge like effluents "alperujo" two phase olive mill waste (TPOMW) are highly biotoxic. Hericium erinaceus is a white rot fungus which produces choice edible mushrooms on substrates rich in lignocellulosics, and its suitability for the treatment of olive by products was examined for the first time. Fungal growth resulted in a notable reduction of OMW's pollution parameters (i.e. 65 decolorization, 47 total phenolic reduction, and 52 phytotoxicity decrease) and correlated with laccase and manganese peroxidase activities. Solid state fermentation of various mixtures of OLPR, TPOMW, and beech sawdust (control) by H. erinaceus qualified OLPR in subsequent cultivation experiments, where it exhibited high mushroom yields and biological efficiency (31 Analyses of proximate composition and bioactive compound content revealed that mushrooms deriving from OLPR substrates showed significantly higher crude fat, total glucan, b glucan, total phenolics, and ferric reducing antioxidant potential values than the control. H. erinaceus demonstrated the potential to detoxify OMW and bioconvert OLPR into high quality biomass, and hence, this fungus could be successfully exploited for the treatment of such by products.
Applied Biochemistry and Biotechnology