Identification of novel laccase from cyanobacterium Microcystis flos-aquae and enhanced azo dye bioremediation potential

Abstract

Textile industries discharge up to 280,000 tons of dye waste annually, resulting in global pollution and health risks. In Nigeria and other African countries, persistent dyes threaten aquatic life and human health. This study introduces a cost-effective, enzyme-mediated bioremediation alternative using a novel laccase from the cyanobacteriumMicrocystis flos-aquae. This purified enzyme yielded 0.55 % (w/w)with significant activity at 40 °C and pH 4.00. Kinetic studies showed the dependence of M. flos-aquae laccase on Cu²⁺and its inhibition by EDTA and Fe²⁺. The efficacy of the enzyme was demonstrated through rapid decolorization of the azo dye Cibacron Brilliant Blue over a wide temperature and pH range. As this enzyme effectively decolorizes dyes across a broad temperature and pH range, it offers a promising solution for bioremediation of textile effluents.

Keywords: 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid; Cibacron Brilliant Blue; Cyanobacteria; Decolorization; Green Oxidation; Recalcitrant Organic Pollutants.