In-vitro decolorization of recalcitrant dyes through an ecofriendly approach using laccase from Trametes versicolor grown on brewer's spent grain

The potential of in-house produced laccase was investigated for in-vitro decolorization of structurally different industrial dyes. Laccase production was carried out under solid-state fermentation conditions in Erlenmeyer flasks and plastic tray bioreactors using brewer's spent grain (BSG), a common waste from the brewing industry, as a substrate by the well known laccase producer Trametes versicolor ATCC 20869. An attempt was made to improve the laccase production by T. versicolor by supplementing the cultures with different inducers, such as 2,2-azino bis(3-ethylbenzthiazoline-6-sulfonic acid), copper sulfate, ethanol, gallic acid, veratryl alcohol and phenol. Among all the inducers, higher laccase activity of 13506.2 +/- 138.2 IU g(-1) (dry basis) was obtained with phenol concentration of 10 mg kg(-1) substrate in tray bioreactor after 12 days of incubation time. The crude laccase decolorized structurally different dyes with variable decolorization efficiencies of 31.30-87.70% after 48 h incubation with laccase (100 IU L-1). (C) 2012 Elsevier Ltd. All rights reserved.