Hyperstabilization of a thermophile bacterial laccase and its application for industrial dyes degradation

In the present study, a novel extracellular laccase isolated from Geobacillus stearothermophilus ATCC 10149 was entrapped in a bionanocomposite matrix consisting of copper alginate (Cu-alginate) supplemented with the nanoclay bentonite. After optimization, this nanobiocatalyst was able to degrade up to 90% of Remazol Brilliant Blue R (RBBR) without the addition of redox mediators and retained 70% of its initial activity for at least 1440 h, equivalent to more than 288 uses. The incorporation of nanoclay allowed alginate beads to be used in alkaline pH and strengthened its mechanical properties. Besides, this thermophilic laccase was able to decolorize other structurally different synthetic dyes such as Methyl Orange, Malachite Green and Indigo Carmine. These preliminary results suggested that the nanobiocatalyst could be a suitable option for dye decolorization and be further developed for large scale bioremediation of toxic dyes.