Journal of Pure and Applied MicrobiologyVol. 8 No. May 2014 Special Edition

Biodegradation of Diazo Dye Reactive Black 5 with the Isolated Yeast Candida krusei

Caishao Wen, Zhisheng Yu*, Zia Ul Islam and Hongxun Zhang

College of Resources and Environment, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing - 100049, China.

Received on 12 February 2014 and accepted on 29 March 2014



The biodegradation for a diazo dye, Reactive Black 5, was investigated by the isolated yeast, Candida krusei. This strain showed 99.08% decolorization within 24 h in a medium containing 1% (w/v) glucose, 0.1% (w/v) ammonium sulphate, and 100 mg/L dyestuff by inoculating 20% (v/v) yeast culture solution at natural pH, and shaking at 30?C. Its decolorization maintained efficient within the range of the initial dye concentration from 100 mg/L to 500 mg/L. Furthermore, the degradation of Reactive Black 5 resulted in a significant pH decrease by this yeast. UV-Vis analysis of batch culture solutions and color observation of cell mats indicated that the decolorization proceeded dominantly by biodegradation, while biosorption happened in the incomplete dye degradation. In addition, this yeast could also remove other dyes such as Reactive Blue 4, Mordant Blue 1, Mordant Yellow 10, and Reactive Red 24.

Keywords : Biodegradation; Diazo dye; Reactive Black 5; Candida krusei.