Evaluation of Acinetobacter sp. B9 for Cr (VI) resistance and detoxification with potential application in bioremediation of heavy-metals-rich industrial wastewater

Abstract

Present work demonstrates Cr (VI) detoxification and resistance mechanism of a newly isolated strain (B9) of Acinetobacter sp. Bioremediation potential of the strain B9 is shown by simultaneous removal of major heavy metals including chromium from heavy-metals-rich metal finishing industrial wastewater. Strain B9 tolerate up to 350 mg L(-1) of Cr (VI) and also shows level of tolerance to Ni (II), Zn (II), Pb (II), and Cd (II). The strain was capable of reducing 67 % of initial 7.0 mg L(-1) of Cr (VI) within 24 h of incubation, while in presence of Cu ions 100 % removal of initial 7.0 and 10 mg L(-1) of Cr (VI) was observed with in 24 h. pH in the range of 6.0-8.0 and inoculum size of 2 % (v/v) were determined to be optimum for dichromate reduction. Fourier transform infrared spectroscopy and transmission electron microscopy studies suggested absorption or intracellular accumulation and that might be one of the major mechanisms behind the chromium resistance by strain B9. Scanning electron microscopy showed morphological changes in the strain due to chromium stress. Relevance of the strain for treatment of heavy-metals-rich industrial wastewater resulted in 93.7, 55.4, and 68.94 % removal of initial 30 mg L(-1) Cr (VI), 246 mg L(-1) total Cr, and 51 mg L(-1) Ni, respectively, after 144 h of treatment in a batch mode.

Cr(VI) Reduction and Cr(III) Immobilization by Acinetobacter sp. HK-1 with the Assistance of a Novel Quinone/Graphene Oxide Composite

“…10 The Cr(VI) reduction rate generally ranged from 0.24 to 2.22 mg Cr(VI) L −1 h −1 . 3,5 In the present study, the newly isolated strain Acinetobacter sp. HK-1 was capable of simultaneously reducing Cr(VI) (1.64 mg Cr(VI) L −1 h −1 at an initial concentration of 55 mg L −1 ) to Cr(III) and immobilizing Cr(III) under anaerobic conditions.…”

“…As shown in eq 6, Cr(III) was theoretically immobilized into the form of insoluble Cr(OH) 3 . In fact, when organic substances existed in medium or were secreted by bacteria, highly soluble organo-Cr(III) end-products would be produced.…”

“…41 Thus, biotreatment methods are widely studied for Cr(VI) remediation. [3][4][5][6][7][8][9][10]40 It was reported that the tannery, electroplating and metal-based industry wastewaters (pH 2.0−8.3) generally contained 14.16−534 mg L −1 Cr, 4.2−13.7 mg L −1 Fe(III), and 19.8 mg L −1 SO 4 2− . 3,42,43 If traditional biotreatments were used, Fe(III) and SO 4 2− can be reduced by iron and sulfate-reducing bacteria, respectively, and then the formed Fe(II) and sulfide reduce Cr(VI).…”

Novel hydrocarbonoclastic metal-tolerant Acinetobacter and Pseudomonas strains from Aconcagua river oil-polluted soil

“…Acinetobacter strains tolerant to chromium, nickel and cadmium that are useful for heavy metal bioremediation have been described (Bhattacharya and Gupta, 2013). In this study, almost all Acinetobacter isolates were able to grow on n-hexadecane as sole carbon source and possessed tolerance to copper and cadmium.…”

Simultaneous Bioremediation of Phenol and Cr (VI) from Tannery Wastewater Using Bacterial Consortium

“…Estimation of total chromate concentration in the sample was done using atomic absorption spectrophotometer (AAS) after acid digestion of the sample (Bhattacharya and Gupta, 2013).…”