Effect of Chromium Forms on the Biodegradation of Reactive Black-5 Azo Dye by Psychrobacter and Klebsiella species

Abstract

To cite his paper: Khalid, A., J. Arshad, S. Mahmood, I. Aziz and M. Arshad, 2015 AbstractAzo dyes and chromium (Cr) are released in the wastewater of leather processing industry during tanning process. Several species of bacteria have shown ability to degrade azo dyes individually; however, presence of Cr ions in industrial effluents may affect the bacterial efficiency of removing azo dyes from waste water. In this study, biodegradation of reactive black-5 dye was studied in a mineral salts medium (MSM) liquid culture in the presence of Cr ions. Two bacterial strains Psychrobacter alimentarius KS23 and Klebsiella oxytoca N7 capable of degrading azo dyes were used individually as well as in a consortium for the degradation of azo dyes. Cr was applied in the form of K2Cr2O7, CrCl3, Cr2(SO4)3 at different concentrations (ranging from 0-250 mg L -1 ) of Cr. The results showed that presence of Cr in mineral salt medium significantly inhibited the azo dye decolorization. In the absence of Cr salts, complete decolorization of 100 mg dye L -1 was achieved by the bacterial strains in 8-12 h while up to 83% decolorization occurred in 72 h at 100 mg L -1 Cr. The rate of decolorization considerably decreased with increasing concentration of azo dye in the presence of 50 mg Cr L -1 medium. These findings imply that the existence of Cr in wastewater can significantly affect the bacterial efficiency in wastewater treatment systems to degrade azo dyes.

Optimización de las condiciones de crecimiento de la bacteria endófita Klebsiella oxytoca en matraz y en biorreactor

“…Klebsiella oxytoca ha sido utilizada con fines biotecnológicos en diversas áreas, presenta potencial biorremediador, pues degrada hidrocarburos [11], compuestos orgánicos hidrofóbicos [12], sustancias tóxicas como el cianuro [13], así como insecticidas organoclorados [14], nitrilos [15], ácidos benzoicos [16], colorantes azoicos [17] y el fármaco diclofenaco [18]. Además, se ha reportado la producción de bioelectricidad en conjunto con la degradación de ácidos grasos [19], ha sido capaz de llevar a cabo la desulfuración termofílica de dibenzotiofenos [20], entre otras muchas aplicaciones [21] [22] [23].…”

Molecular identification of dye degrading bacterial isolates and FT-IR analysis of degraded products

“…up to 70-100% [15,16], E. coli up to 78.04% [15] and Klebsiella sps. up to 100% [17]. Bacillus strains are ubiquitous in activated sludge and have been found to degrade different dye groups [18].…”