Artichoke peroxidase to partial removal of phenols from olive mill waste water.

A very large amount of phenol-polluted waters is formed from the production of olive oil (olive mill waste water, OMWW) and their disposal represents a serious problem. The aim of this study was to investigate the use of peroxidase (POD) from artichoke (Cynara cardunculus L. subsp. scolymus (L.) Hayek) leaves to remove phenols present in OMWW. The POD catalyzes the polymerization and precipitation of aqueous phenols. This application could be useful, because in the Mediterranean region a large amount of OMWW as well as a lot of artichoke scraps resulting from artichoke processing industry, are produced. So, it is possible to consider this biomass (leaves and external bud bracts) as a useful and cheap source of peroxidase. The enzyme extraction was performed by homogenization and separation of pigments using an aqueous two phase polymer system (polyethylene glycol/(NH4)2SO4), that allowed the accumulation of POD in the salt phase. The optimal reaction conditions were evaluated. The phenolic concentration was assayed by Folin-Ciocalteu method. Preliminary results showed that the optimal conditions for enzyme activity were in a broad range of both pH (from 4 to 7) and temperature (from 5 to 50°C). In optimal enzymatic conditions, a reduction of more than 60% of initial phenolic concentration was observed.