Enhanced biodecolorization of reactive dyes by basidiomycetes under static conditions

This study presents the biodecolorization potential of basidiomycete fungi Trametes hirsuta, Pycnoporus sp., and Irpex sp. for different reactive dyes viz. Reactive Red 120, Remazol Brilliant Blue R (RBBR), Reactive Orange G, and Reactive Orange 16 under static and shaking conditions. The screening trials revealed that T. hirsuta exhibited maximum potential (83.75 %) for biodecolorization of RBBR dye under static conditions after the fifth day of incubation. However, the rate of biodecolorization of RBBR dye by Pycnoporus sp. was much slow and reached maximum (81.25 %) after 15 days of incubation under shaking conditions. By process optimization, enhanced decolorization (91.2 %) of RBBR by T. hirsuta was achieved at pH 5.5 within 24 h using a defined salt medium amended with p-coumaric acid under static conditions. pH was found to be an important parameter for the enzymatic system involved in RBBR dye decolorization by T. hirsuta and Pycnoporus sp. Biodecolorization of RBBR dye was determined by a reduction in optical density at the wavelength of maximum absorbance (λ, 578 nm) by UV-vis spectrophotometer. The shift in maximum wavelength toward shorter/longer wavelength in UV-vis scanning spectrum revealed the degradation of RBBR dye into different transformation products.