Characterization of phenolic compounds of OMW: toxicity and degrability by yeasts

The olive oil extraction, performed by the 3-phases process, results on a large amount of an effluent, usually known as Olive Mill Wastewater (OMW). It is mainly produced in the Mediterranean area, with the exception of Spain that is one of the major producers but mostly use the 2-phases process. OMW represents a major environmental problem due to its high organic content, being characterized by a strong acidic smell and an intensive brown to dark color due to the presence of biodegradable, recalcitrant and biostatic compounds. OMW phytotoxicity can be attributed to the phenolic compounds (Lanciotti et al, 2005). Owing to their instability, OMW phenols tend to polymerise during storage into condensed high-molecular-weight polymers that are difficult to degrade (Crognale et al, 2006). Thus, uncontrolled OMW disposal can create severe risks to water and soil quality. OMW is currently concentrated by evaporation in open pools, but this method is not satisfactory because a black foul-smelling sludge, difficult to remove, is produced. Instead of disposal solutions an approach of using this waste as a resource to be valorized is of greater interest. In fact, OMW contains sugars, lipids, mineral elements and phenolic compounds (10 % of the organic matter) that could be either directly recovered by chemical extraction and subsequent purification, or utilized as a basis for fermentative processes.

Characterization of phenolic compounds of OMW: toxicity and degrability by yeasts Conference Paper