Ochrobactrum tritici strain 5bvl1 — characterization of a Cr(VI)-resistant and Cr(VI)-reducing strain

Abstract

Bacterial strain 5bvl1, isolated from a chromium-contaminated wastewater treatment plant and identified as Ochrobactrum tritici, was resistant to a broad range of antibiotics, to Cr(VI), Ni(II), Co(II), Cd(II), and Zn(II), and was able to grow in the presence of 5% NaCl and within the pH range 4-10. Characterization showed that strain 5bvl1 could be considered a halotolerant and alkalitolerant microorganism resistant to high concentrations of Cr(VI). This strain was able to grow aerobically in up to 10 mmolxL(-1) Cr(VI). Cr(VI) resistance was independent of sulphate concentration. Under aerobic conditions strain 5bvl1 was also able to reduce high Cr(VI) concentrations (up to 1.7 mmolxL(-1)). Increasing concentrations of Cr(VI) in the medium lowered the growth rate of strain 5bv11 but the reduction in growth rate could not be directly correlated with the amount of Cr(VI) reduced. Unlike the type strain, which was only able to reduce Cr(VI), strain 5bvl1 was resistant to Cr(VI) and able to reduce it. Moreover, in strain 5bvl1, the rate and extent of Cr(VI)-reduction were higher than in the other strains of the genus Ochrobactrum. Ochrobactrum strain 5bvl1 resists high Cr(VI) concentrations and has a high Cr(VI)-reducing ability, making it a valuable tool in bioremediation.

Chromium (VI) Reduction by Cell Free Extract of Ochrobactrum anthropi Isolated from Tannery Effluent

“…The partial 16S rRNA gene sequence of STCr-1 was submitted and the GenBank accession number of this strain was DQ989207. Cr(VI) resistant Ochrobactrum strains have been reported previously but they are resistant to quite lower concentration of Cr(VI) (Francisco et al 2002;Branco et al 2004;He et al 2009). All these features make this strain a model contestant to be used in developing a bioremidial process for Cr(VI)-contaminated environments under a broad range of environmental conditions.…”

The Chromate-Inducible chrBACF Operon from the Transposable Element Tn OtChr Confers Resistance to Chromium(VI) and Superoxide

“…This strain was isolated from chromiumcontaminated sludge from a wastewater treatment plant receiving wastewaters from tannery industries (14) and was found to be able to grow in the presence of high concentrations of chromate (8). Different alphaproteobacteria belonging to the genus Ochrobactrum have been isolated from clinical and/or environmental samples; however, little is known about their genetic organization and general resistance abilities.…”

Microbial Fuel Cell Inoculated with Ochrobactrum Tritici KCC210 for Chromium (VI) Measurement in Electroplating Wastewater

“…Figure 2A indicates that a pH of 5-10 led to >75% removal efficiency and an optimal pH range of pH 6-8, >92% removal efficiency could be achieved. This characteristic illustrates O. tritici KCC210 is alkalotolerant and favors the application of the MFC biosensor in measuring Cr(VI) concentration in different water bodies [21]. Figure 2B illustrates the effects of temperature on Cr(VI) removal efficiency of O. tritici KCC210.…”