Molecular identification and characterization of novel Hypocrea koningii associated with azo dyes decolorization and biodegradation of textile dye effluents

Abstract

The potential of six fungi (three basidiomycetes biocontrol agent – Trichoderma spp. and three ascomycetes phytopathogens) were evaluated for decolorization and biodegradation of five azo dyes (Red HE7B, Reactive Violet-5, Red Black-B, Light Navy Blue HEG, Dark Navy Blue H2GP) used for textile industries. The fungi were isolated from effluent contaminated plant rhizosphere near textile dyeing industrial area and identified as Trichoderma viride, Trichoderma koningii, Trichoderma harzianum, Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum based on macro and micro-morphological descriptors. T. koningii was recognized as the best decolorizer based on the average decolorization rate of five azo dyes followed by A. niger. These two fungal isolates were studied further for biodegradation of textile dye effluents. Fungal biodegradation was assessed by HPLC profile and physicochemical analysis. The biological oxygen demand and chemical oxygen demand of effluents were efficiently reduced by T. koningii compared with A. niger. T. koningii JAU8 isolate was characterized by 28S rRNA gene sequence using ITS markers. Comparison of test strain against known sequences of 28S rRNA gene databases was evident 86% similarity. Molecular approach identified a new strain Hypocrea koningii (teleomorphs of anamorphic Trichoderma), untested before for bioremediation purposes, proved to have a high potential in decolorizing azo dyes.