Olive mill wastewater remediation by means of Pleurotus ostreatus

Results of a research program on raw olive-mill wastewater (OMW) bioremediation are presented. Bioremediation experiments have been carried out both in an airlift bioreactor and in aerated flasks, using Pleurotus ostreatus. The process was investigated under controlled non-sterile operating conditions, representative of industrial operation. Growth of P. ostreatus as well as polyphenols conversion were assessed. OMW bioconversion was characterized in terms of total organic carbon, polyphenols concentration, phenol oxidase activity, extent of decolourization and pH as a function of time. Results demonstrate that: P. ostreatus effectively grows on raw OMW; polyphenols abatement is controlled by the availability of nutrients and can be as large as 95%; bioconversion of non-sterilized OMW does not result into appreciable decolourization of the liquid medium. The use of an internal loop airlift bioreactor as a candidate for the full-scale implementation of an OMW aerobic bioremediation process is demonstrated.