Aerobic decolorization and degradation of Acid Red B by a newly isolated Pichia sp TCL

A yeast strain with strong abilities to decolorize various azo dyes aerobically was isolated from the sea mud. The strain designated as TCL was identified as Pichia sp. on the basis of 18S rDNA analysis. More than 90% of Acid Red B (100 mg/L) was decolorized within 10 h in the Martin Broth at 30 degrees C and 150 r/min, and strain TCL could tolerate up to 1000 mg/L of the dye. Meantime, the effects of different physicochemical parameters (media, concentrations of glucose, NH4Cl, initial dye and NaCl) were investigated to improve the removal efficiency. The significant biodegradation process of Acid Red B rather than inactive surface adsorption was confirmed by UV-vis, HPLC analysis and colorless microbial cells. In addition, the metabolic products and partial degradation pathway were proposed with the help of HPLC-MS analysis. To the best of our knowledge, it is the first time that a yeast strain of Pichia sp. has been reported with the excellent decolorizing ability against azo dyes under shaking conditions. This work conferred the utilization possibility of strain TCL in the biological treatment of dyeing wastewater. (C) 2012 Elsevier B.V. All rights reserved.