Biodegradation and metabolic pathway of cresol red dye by selected fungi

Abstract

Massive amount of dye concentrations has been released into the environment as wastewater. Cresol red dyes remains as one of the most difficult dyes to be degraded. In this study, 20 different types of white rot fungi were isolated from a decayed wood in UTM forest and labelled as M 01-M 20. These fungi were screened fortheir ability to degrade cresol red dye after 30 days of incubation. New metabolic pathways of degradation of cresol red dyes by fungi M06 and M15 were explored in this research. Both M06 and M15 were chosen based on their ability to decolorize 10 ppm cresol red dye on agar and liquid medium. These fungi were further tested for their ability to degrade cresol red dye inliquid medium under several conditions which is carbon and nitrogen sources, pH, salinity and effect of different concentration of surfactant (Tween 80). From decolorization, M06 showed efficient decolorization with addition of glucose (60.01%), ammonium sulphate (67.22%), Tween 80 0.1 mL (53.82%), 50 g/L of NaCl concentration (59.64%) and pH 3 (67.50%). Meanwhile, M15 showed efficient degradation of cresol red dye with addition of glucose (72.85%), ammonium nitrate (82.40%), Tween 80 0.1 mL (74.35%), 150 g/L of NaCl concentration (78.64%) and pH 3 (85.46%). These fungi were then identified using 18s rRNA sequence analysis method. From the phylogenetic tree, fungi M06 belongs to Trichdermaharzianum and fungi M15 belongs to Absidiaspinosa. Identification of metabolites was performed by combining several series of experiment through the use of UV-vis Spectrophotometer, Thin Layer Chromatography, and Gas Chromatography Mass Spectrophotometer. The analytical results showed that 2-hydrozybenzoic acid, and 2, 4-dyhidroxybenzoic acid were formed during the degradation of cresol red dye by TrichodermaharzianumM06. In the case of AbsidiaspinosaM15, benzoic acid and benzeneacetic acid were identified as the metabolic products produced during the degradation of cresol red dye. From the study, it is found that M 06 and M 15 have the capability to degrade cresol red dye.For further investigation, several experiments can be carried out to enhance the use of the isolated fungi in textile wastewater treatment.