Immobilized laccase mediated dye decolorization and transformation pathway of azo dye acid red 27.
BACKGROUND
Laccases have good potential as bioremediating agents and can be used continuously in the immobilized form like many other enzymes.


METHODS
In the present study, laccase from Cyathus bulleri was immobilized by entrapment in Poly Vinyl Alcohol (PVA) beads cross-linked with either nitrate or boric acid. Immobilized laccase was used for dye decolorization in both batch and continuous mode employing a packed bed column. The products of degradation of dye Acid Red 27 were identified by LC MS/MS analysis.


RESULTS
The method led to very effective (90%) laccase immobilization and also imparted significant stability to the enzyme (more than 70% after 5 months of storage at 4°C). In batch decolorization, 90-95% decolorization was achieved of the simulated dye effluent for up to 10-20 cycles. Continuous decolorization in a packed bed bioreactor led to nearly 90% decolorization for up to 5 days. The immobilized laccase was also effective in decolorization and degradation of Acid Red 27 in the presence of a mediator. Four products of degradation were identified by LC-MS/MS analysis.


CONCLUSIONS
The immobilized laccase in PVA-nitrate was concluded to be an effective agent in treatment of textile dye effluents.
Department of Biology, Indian Institute of Technology-Jodhpur, Jodhpur, 342011 Rajasthan India.
Meenu
M
Chhabra
Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz-Khas, New-Delhi, 110016 India.
Saroj
S
Mishra
Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz-Khas, New-Delhi, 110016 India.
Trichur Ramaswamy
TR
Sreekrishnan
Acid Red 27; Azo dye degradation; Immobilization; Laccase-mediator; Polyvinylalcohol beads