Crosslinked enzyme aggregates (CLEAs) of laccases from Pleurotus citrinopileatus induced in olive oil mill wastewater (OOMW)

Abstract

The enzymatic factory of ligninolytic fungi has proven to be a powerful tool in applications regarding the degradation of various types of pollutants. The degradative potential of fungi is mainly due to the production of different types of oxidases, of which laccases is one of the most prominent enzymatic activities. In the present work, crude laccases from the supernatant of Pleurotus citrinopileatus cultures grown in olive oil mill wastewater (OOMW) were immobilized in crosslinked enzyme aggregates (CLEAs), aiming at the development of biocatalysts suitable for the enzymatic treatment of OOMW. The preparation of laccase CLEAs was optimized, resulting in a maximum of 72% residual activity. The resulting CLEAs were shown to be more stable in the presence of solvents and at elevated temperatures compared to the soluble laccase preparation. The removal of the phenolic component of OOMW catalyzed by laccase-CLEAs exceeded 35%, while they were found to retain their activity for at least three cycles of repetitive use. The described CLEAs can be applied for the pretreatment of OOMW, prior to its use for valorization processes, and thus, facilitate its complete biodegradation towards a consolidated process in the context of circular economy.