Decolorizing synthetic dyes with fungi screened from a Phyllostachys violascens stand

Abstract

This study aimed to screen high efficiency decolorizing fungi for degradation of structurally different synthetic dyes. Fungal strains were isolated and screened from soil of bamboo plantation (Phyllostachys violascens) using conventional separation, cultivation methods, and sequence alignment analysis of nuclear ribosomal internal transcribed spacers (ITS). The bamboo plantation for isolating soil fungi consisted of bamboo forests aged 1, 7, 12, and 15 years, which applied no heavy fertilization and organic mulch until year 5. Result showed that Trichoderma sp. had the highest isolation frequency in the cultured fungi from topsoil based on morphological identification and phylogenetic analysis. Decolorization capacity of the five isolated fungi ((P7-2-1, P7-2-2, P1-2-2, P7-2-3, P12-2-4) to the five different synthetic dyes (Congo red, orange G, crystal violet, fuchsin acid, and methyl orange) showed that P7-2-3 (identified as Mucor circinelloides) and P12-2-4 (identified as Trichoderma spp.) had the strongest capacity to decolorize the five kinds of dyes. The decolorization efficiency of P7-2-3 and P12-2-4 to crystal violet was similar at different crystal violet concentrations below 500.0 mg·L-1; however, crystal violet inhibited the decolonization reaction at concentrations of 300.0 mg·L-1 for strain P7-2-3 and 400.0 mg·L-1 for strain P12-2-4. The fungal biomass and dye decolorization had a positive relationship for different concentrations of crystal violet, and strains of P7-2-3 and P12-2-4 have potential value for application in decolorization and degradation of dyes wastewater. [Ch, 4 fig. 2 tab. 31 ref.]