Relationships between the abilities of streptomycetes to decolorize three anthron-type dyes and to degrade lignocellulose

Abstract

Fourteen Streptomyces strains known to degrade lignocellulose were screened for their ability to decolorize three anthron-type dyes: Remazol Brilliant Blue R (RBBR), blue poly(vinylamine) sulfonate – anthraquinone dye (Poly B-411), and red poly(vinylamine) sulfonate – anthrapyridone dye (Poly R-478). The relationships between efficiency of dye decolorization and capacity to attack lignocellulose were examined. Good correlation was found between lignocellulose weight losses observed during previous solid-state fermentation assays and the ability to decolorize RBBR and Poly B-411. A poor correlation was observed between Poly R-478 decolorizing activity and lignocellulose-degrading ability. The presence of corn stover lignocellulose in the culture broth enhanced decolorization of the dye by all but one of the strains. The enhancement was thought to involve the increased production of extracellular peroxidases by cultures growing on lignocellulose. The results on oxidation of the three dyes by a commercial horseradish peroxidase indicate that RBBR and Poly B-411 are suitable substrates for analyzing production of peroxidases by Streptomyces spp., while no decolorization of Poly R-478 was observed under the conditions used. However, Poly R-478 decolorizing activity of the Streptomyces may reflect the activity of other enzymes involved in the complex process of lignocellulose degradation. Key words: Streptomyces, lignocellulose, degradation, dye, decolorization.