A perspective for OMW valorization through integration of lipase production fermentation and anaerobic digestion

Abstract

The olive mill wastewaters (OMW) are a major problem in the mediterranian basin countries, the world’s leading producers of olive oil. The present work aims the OMW valorization by producing high-value compounds while degrading this effluent. The OMW is submitted to a lipase-producing aerobic fermentation that contributes for a partial OMW degradation, followed by an anaerobic methanogenic degradation process. The results obtained showed that the aerobic treatment, with production of lipase, had a positive effect on the anaerobic degradation of the OMW. Methane yields were higher in the vials supplemented with treated OMW, relatively to the ones with raw OMW. Best results were achieved for the concentration of 5 g COD-treated OMW L-1, where 78% of the COD added was recovered as methane. The lipase produced on the aerobic step, when not removed, exhibited loss of activity (60-95%) throughout the anaerobic process.