Sorghum-grown fungal biocatalysts for synthetic dye degradation

Yifan Gao; Benjamin Croze; Quinn T Birch; Mallikarjuna N Nadagouda; Shaily Mahendra

doi:10.1016/j.wroa.2023.100181

Sorghum-grown fungal biocatalysts for synthetic dye degradation

Water Res X. 2023 Apr 30:19:100181. doi: 10.1016/j.wroa.2023.100181. eCollection 2023 May 1.

Authors

Yifan Gao¹, Benjamin Croze¹, Quinn T Birch², Mallikarjuna N Nadagouda³, Shaily Mahendra¹

Affiliations

¹ Department of Civil and Environmental Engineering, University of California, Los Angeles, 580 Portola Plaza, Los Angeles, CA 90095, USA.
² Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA.
³ United States Environmental Protection Agency, Office of Research & Development Center for Environmental Solutions & Emergency Response, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA.

Abstract

The synthetic dye discharge is responsible for nearly one-fifth of the total water pollution from textile industry, which poses both environmental and public health risks. Herein, a solid substrate inoculated with fungi is proposed as an effective and environmentally friendly approach for catalyzing organic dye degradation. Pleurotus ostreatus was inoculated onto commercially available solid substrates such as sorghum, bran, and husk. Among these, P. ostreatus grown on sorghum (PO-SORG) produced the highest enzyme activity and was further tested for its dye biodegradation ability. Four dye compounds, Reactive Blue 19 (RB-19), Indigo Carmine, Acid Orange 7, and Acid Red 1 were degraded by PO-SORG with removal efficiencies of 93%, 95%, 95%, and 78%, respectively. Under more industrially relevant conditions, PO-SORG successfully degraded dyes in synthetic wastewater and in samples collected from a local textile factory, which reveals its potential for practical usage. Various biotransformation intermediates and end-products were identified for each dye. PO-SORG exhibited high stability even under relatively extreme temperatures and pH conditions. Over 85% removal of RB-19 was achieved after three consecutive batch cycles, demonstrating reusability of this approach. Altogether, PO-SORG demonstrated outstanding reusability and sustainability and offers considerable potential for treating wastewater streams containing synthetic organic dyes.

Keywords: Biocatalysts; Dye biodegradation; Solid-state fermentation; Textile wastewater treatment; White-rot fungus.