New strategies for bioremediation of olive oil mill wastewaters using non-conventional microorganisms

Two approaches were developed in order to select microorganisms suitable to be used in olive mill wastewaters bioremediation. By the first approach, three hundred yeasts were isolated from five industrial mills and identified by molecular analysis. The different strains were selected according to their capacity to grow in OMW (olive mill wastewaters) as the sole carbon source and to reduce phenolics, chemical oxygen demand (COD) and antimicrobial compounds. One Geotrichum candidum isolate was used to set up a whole-cell immobilization system in calcium alginate gel and the COD and phenolic reduction obtained using the immobilized cells showed respectively a 2.2- and 2-fold increase compared to the removal obtained using free cells. By the second approach, a new protocol was developed to isolate and select aerobic microorganisms from different industrial samples and environmental niches (soils, OMWs) and able to detoxify olive mill wastewaters.