Wheat straw-based microbial electrochemical reactor for azo dye decolorization and simultaneous bioenergy generation

Microbial fuel cells have emerged as a technique that can effectively treat wastewater with simultaneous elec-tricity generation. The present study explored the performance of microbial fuel cell for decolorizing and degradation of azo dyes including, remazol brilliant blue (RBB), mordant blue 9 (MB9), acid red1 (AR1), and orange G (OG), while, simultaneously generating electricity. Wheat straw and its hydrolysate was used as a potential substrate in MFC. The hydrolysate was prepared through the degradation of wheat straw by P. floridensis, P. brevispora and P. chrysosporium, while the yeast Pichia fermentans was used as biocatalyst. Dye decolorization was carried out in a fungus-yeast mediated single-chambered MFC batch mode, U-shaped reactor, and bottle reactor in continuous mode. The maximum power density recorded in U shaped continuous reactor was 34.99 mW m- 2 on 21st day of the experiment. The best response of dye decolorization was observed in the case of MB9 (96%) with P. floridensis in the continuous electrochemical reactor followed by RBB (90-95%), OG (76%), and AR1 (38%). The toxicity of the treated wastewater was assessed using phytotoxicity analysis.

Automated summary

Microbial fuel cells are effective in treating wastewater and simultaneously generating electricity. This study explored the performance of microbial fuel cells in decolorizing and degrading azo dyes, with wheat straw and its hydrolysate as potential substrates. The best decolorization response was observed with P. floridensis in the continuous electrochemical reactor, achieving 96% decolorization for MB9.