Abstract
Abstract - In order to obtain a more stable and reusable immobilized spore laccase for dye decolorization, the spores from Bacillus pumilus W3 were immobilized on diethylaminoethyl cellulose (DEAE-cellulose). Free and immobilized spore laccase retained 34.38% and 46.11% of their initial activity, respectively, after 10 days incubation at pH 9.0. Their residual activity remained at 27.36% and 31.84% after 10 h incubation at 70 °C. Immobilized spore laccase was more stable than free spore laccase in the presence of most organic solvents, metal ions and inhibitors. The tested dyes, including methyl green, methyl red and acid red 1, were removed 86.82%, 78.14% and 88.60%, respectively, by immobilized spore laccase after 24 h at 37 °C, and 74.34% of initial decolorization activity after 7 cycles was retained when it decolorized acid red 1. These properties indicated that immobilized spore laccase may be useful in textile effluent treatment. Keywords : Spore laccase; Bacillus pumilus ; DEAE-cellulose; Decolorization; Immobilization.
Highlights
Synthetic dyes are used extensively in textile dyeing and finishing industries
Fungal laccase is usually unstable under high temperatures and alkaline conditions, and no decolorization activities are observed at pH values higher than 7 (Held et al, 2005)
DEAE-cellulose, 4hydroxybenzoic acid (4-HBA), crystal violet, methyl green, methyl red, lysozyme, phenylmethylsulfonyl fluoride (PMSF) and other chemicals were all of analytical grade and purchased from Sinopharm Chemical Reagent Company (Shanghai, China)
Summary
Synthetic dyes are used extensively in textile dyeing and finishing industries. Growing demand of dyes in the textile industry makes it one of the main sources of water pollution problems (Sarayu and Sandhya 2012). White-rot fungi are the most efficient single class of microorganisms in breaking down synthetic dyes (Wesenberg et al, 2003). Fungal laccase is usually unstable under high temperatures and alkaline conditions, and no decolorization activities are observed at pH values higher than 7 (Held et al, 2005). Bacterial laccase can withstand high temperature and extreme pH values (Zhang et al, 2012)
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