Olive mill wastewater biological assessment: Optimization and identificationof compounds degrading yeasts

Abstract

The present work aims to evaluate the capacity of a yeast strain to degrade the olive mill wastewater(OMWW) and to obtain a stabilized product that can be disposed without any environmental impacton the water–soil–plant system. The pollutant load, expressed by the chemical oxygen demand(COD) and the phenolic compounds (PC), are 187.63 and 4.30 g/L, respectively. The evaluationof the yeast strain capacity to develop on liquid and solid culture media based on the OMWWat different dilutions of 25%, 50%, 75%, raw matter, allowed us to optimize the abatement of thepollutant load, particularly, PC. The results show a significant reduction of 98% for the COD and97% for the PC, after 1 month of treatment at a dilution of 25%. The PC extracts were characterizedby high-performanceliquid chromatography, the main identified PC are hydroxytyrosol, tyrosol,caffeic acid, p-coumaric acid and oleuropein. Most of which had disappeared after the treatment. Theselected yeast strain was identified by 26S rDNA sequencing and shows that belongs to the speciesof Rhodotorulamucilaginosa.