Detoxification and decolorization of complex textile effluent in an enzyme membrane reactor: batch and continuous studies.

Autor:	Dahiya M; Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India., Islam DT; Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India., Srivastava P; Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India., Sreekrishnan TR; Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India., Mishra S; Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India.
Jazyk:	angličtina
Zdroj:	Frontiers in microbiology [Front Microbiol] 2023 Jul 07; Vol. 14, pp. 1193875. Date of Electronic Publication: 2023 Jul 07 (Print Publication: 2023).
DOI:	10.3389/fmicb.2023.1193875
Abstrakt:	There is an urgent need to look for bio-based technologies to address the pollution related to textile dyes in waterbodies. The aim of this study was to evaluate an engineered laccase variant, LCC1-62 of Cyathus bulleri , expressed in recombinant Pichia pastoris , for the decolorization and detoxification of real textile effluent. The partially purified laccase effectively (~60-100%) decolorized combined effluent from different dyeing units at a laccase concentration of 500 U/L at a 50-mL level. Decolorization and detoxification of the combined effluents, from a local textile mill, were evaluated at 0.3 L volumetric level in a ray-flow membrane reactor in batch and continuous modes of operation. In batch studies, maximum decolorization of 97% and detoxification of 96% occurred at a hydraulic retention time (HRT) of 6 h without any additional laccase requirement. In continuous studies, the reactor was operated at an HRT of 6 h with a lower enzyme dosage (~120 U/L of the effluent). Decolorization was accompanied by a loss in laccase activity which was restored to ~120 U/L by the addition of laccase in two regimes. The addition of laccase, when the residual laccase activity decreased to 40% (~50 U/L), resulted in high decolorization (~5 ppm residual dye concentration) and low variance (σ 2 ) of 2.77, while laccase addition, when the residual dye concentration decreased to ~8% (~10 U/L), resulted in an average dye concentration of 13 ppm with a high variance of 62.08. The first regime was implemented, and the continuous reactor was operated for over 80 h at an HRT of 3 and 6 h, with the latter resulting in ~95% decolorization and 96% reduction in the mutagenicity of the effluent. Less than 10% membrane fouling was observed over long operations of the reactor. The findings strongly suggest the feasibility of using LCC1-62 in an enzyme membrane reactor for large-scale treatment of textile effluents. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2023 Dahiya, Islam, Srivastava, Sreekrishnan and Mishra.)
Databáze:	MEDLINE
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