One-pot laccase@MOF biocatalysts efficiently remove bisphenol A from water

The presence of bisphenol A (BPA) in wastewater, its toxicity and the hardness for its complete degradation constitutes a serious environmental problem and a scientific challenge. The enzyme laccase is an oxidoreductase capable of oxidizing phenolic compounds, being one of the most efficient biocatalysts for BPA removal. The immobilization of laccases to lead solid biocatalysts is essential for their applications as it allows their stabilization and easy recovery from the liquid reaction media and subsequent reuse. This work compares the efficiency of siliceous-type supports, which have traditionally been used for this purpose, with the use of MOF-type supports. Thanks to the versatility in the synthesis methods offered by MOFs, MOF-type biocatalysts can be prepared in a one-pot using an in-situ procedure (Lac@NH2-MIL-53(Al)) under conditions compatible with enzymatic activity (room temperature, aqueous solution and moderate pH values). The resulting biocatalyst displays a high enzyme loading of 100 mg.g-1 which is also permanent: free of enzyme leaching. As opposed, post-synthesis in two steps: Lac#NH2-MIL-53(Al) (with low enzyme loading) and Lac#Amorphous silica-NH2 (100 mg.g-1 enzyme loading, but high rate of enzyme leaching) were also prepared and compared.