Chromate Reduction in Anaerobic Systems by Bacterial Strain Pseudomonas aeruginosa CRM100

Abstract

The biological reduction of soluble chromate(VI) compounds by bacteria was investigated as a possible treatment for industrial wastewater. A chromate(VI) reducing bacterial strain CRM100 was isolated from a wastewater treatment plant and identified as Pseudomonas aeruginosa. Strain CRM100 using citrate as carbon source, was able to reduce 99.8 % of chromate(VI) added at a concentration of 100 mg L -1 . The results demonstrated the potential applicability of CRM100 for the bioremediation of heavy metal contaminated wastewater. Figure 5. Inhibition of sulfate, nitrate and chromate reduction. The initial concentration of sulfate, nitrate and chromate was 100 mg L -1 . 350 mg L -1 perchlorate and 250 mg L -1 tungstate inhibit the nitrate and sulfate reduction, respectively. The growth of CRM100 is inhibit by concentrations of 1000 mg L -1 perchlorate and 1500 mg L -1 tungstate.

Chemical-Assisted Microbially Mediated Chromium (Cr) (VI) Reduction Under the Influence of Various Electron Donors, Redox Mediators, and Other Additives: An Outlook on Enhanced Cr(VI) Removal

“…Usually, the abundant oxygen-containing functional groups (C–O, CO–OH, C–OH, and C–O–R) in organic matters present the utility as electron donors (π electrons) ( Choppala et al, 2016 ; Shaheen et al, 2019 ; Xu et al, 2019 ). Glucose, fructose, lactose, pyruvate, lactate, citrate, glycerol, acetate, formate, NADH/NADPH, reduced glutathione, etc., are the various popular electron donors for Cr(VI) reduction ( Garbisu et al, 1998 ; Poopal and Laxman, 2009 ; Murugavelh and Mohanty, 2013 ; Salamanca et al, 2013 ; Ahemad, 2014 ; Mala et al, 2015 ). Many such examples for the treatment of Cr(VI) can be further studied from Table 2 .…”

Bacterial Reduction of Cr(VI): Operational Challenges and Feasibility

“…Various types of bacterial species have been reported to be able to reduce Cr(VI) to Cr(III) which include Pseudomonas sp., Bacillus sp., Microbacterium sp., and Shewanella oneidensis [31]. Most of the reported aerobic Cr(VI) reductases have been found intracellular [32•].…”

“…Anaerobic reduction of Cr(VI) has been reported to proceed through simultaneous Cr(VI) reduction and methane oxidation in a membrane-based biofilm reactor. However, it was postulated that energy generated in the anaerobic respiration process is insufficient to sustain cell growth because fermentable organic compounds generated is utilised for cell metabolism [31,38]. Initial pH of Cr(VI) in wastewater, i.e., 0.50-3.75 ± 0.05, was reported not to interfere with the survival of Cr(VI)-reducing bacteria as the final pH of the mixture between Cr(VI) and the growth medium (nutrient broth) would be between 6.80 to 7.65 ± 0.05.…”