Laccase enzyme production from <i>Trametes versicolor</i> : a sustainable approach to treat raw dye bath textile effluent
Baby Malleswari Ramayanam
Abstract
Laccase, a blue multicopper oxidase, has significant biotechnological and environmental applications. This study focuses on optimizing laccase production from Trametes versicolor (UC-3) through submerged fermentation under various nutritional conditions, achieving a two-fold increase in enzyme yield. The highest laccase production (49.2 U/mL) was observed at 30 °C, pH 5.5, with 0.2 mM CuSO4, under shaking conditions at 200 rpm over 6 d. The purified laccase had a molecular weight of 66 kDa, demonstrated stability across a broad pH range (2.5 – 9.5), and retained 90% activity at temperatures up to 70 °C, with optimal activity at 30 °C using 2,2’-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and guaiacol as substrates. Complete inhibition occurred with sodium azide (5 mM), while ferric chloride (1 mM) exhibited the highest inhibition among tested metallic salts. Additionally, laccase-mediated decolorization of textile dyeing effluent achieved an impressive 99% reduction in color. The raw textile dyeing effluent and treated were analyzed through FTIR and determined the N = N (azo group) bond degradation. These findings present a cost-effective strategy for enhancing laccase production from Trametes versicolor and underscore its potential for treating textile dyeing effluent effectively.