Reactive Black 5 decolorization using immobilized Brown-rot fungus Gloeophyllum trabeum

Reactive Black 5 (RB5) is one of the most common synthetic reactive dyes that requires treatment due to its effect on the water ecosystems and human health (e.g., cancer), therefore, it needs to be treated. This study aimed to decolorize RB5 dye using the immobilized brown-rot fungus, Gloeophyllum trabeum, on sodium alginate (SA). The immobilized beads involved two variations, living and dead fungus (biomass), entrapped into 2% (w/v) SA and solidified by chilled CaCl₂. The result showed that the immobilized G. trabeum biomass exceeded the abilities of the living fungus after 7 days of incubation. Using the spectrophotometric method, the RB5 decolorization percentages by immobilized living and dead fungus were 13.35% and 53.08%, respectively. The decolorization abilities were affected by several factors, such as dye concentration, temperature, pH, and static or agitated conditions. Optimum conditions for decolorizing RB5 by dead fungus G. trabeum beads were incubation time 7 days, initial dye concentration 50 mg/L, pH 7.0, temperature 40 ˚C, and under shaking conditions. Meanwhile, for living fungus G. trabeum beads, the initial concentration was 50 mg/L, pH 3.0, temperature 25 ˚C, and under static conditions. In addition, the isothermal adsorption kinetics of RB5 by the dead and living fungus beads followed the Langmuir and Freundlich model, respectively.