Biodegradation of dye-containing wastewater by fusant strains using a sequential anaerobic–aerobic process

Abstract

A fusant strain T1, which was constructed by protoplast fusion between Acinetobacter sp. SRL8, Escherichia sp. XBR68 and Acinetobacter sp. RC10, could simultaneously decolorize three different dyes, namely reactive brilliant blue XBR, disperse orange SRL, and red base RC. Maximum decolorization of initial 30 mg L⁻¹ was achieved at pH 7.0, 35°C and 3% inoculum (v/v) under anaerobic condition during 24 h incubation. The decolorization ratio for XBR, SRL, and RC by the strain T1 could reach 91.5, 87.6, and 65.7%, respectively. Supplementation with appropriate concentration of glucose (0.2%, w/v) in the decolorization reaction system could further enhance decolorization percent. The strain T1 was highly tolerant to three different dyes up to 400 mg L⁻¹. Biological decolorization of the three different dyes by the strain T1 was investigated in a sequential anaerobic/aerobic process. The reaction system was operated at room temperature. The results indicated that over 95% color removal was obtained in anaerobic process and 97.6% COD removal occurred in the aerobic process.

Keywords:

• Microbial decolorization
• Protoplast fusion
• Anthraquinone dye
• Azo dye
• Biodegradation kinetics

Acknowledgments

The research was financially funded by the grants “National Natural Science Foundation” (Project No. 11275033) and the Talent Introduction Foundation of Changzhou University (No. ZMF13020003).