Direct Cr (VI) bio-reduction with organics as electron donor by anaerobic sludge

Qian, Jin; Zhou, Jun‐Mei; Wang, Lianlian; Li, Wei; Li, Qin; Wang, Dongbo; Wang, Qilin

doi:10.1016/j.cej.2016.10.077

Cited by 71 publications

(18 citation statements)

References 31 publications

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“… Lu et al (2020) found that natural material, mackinawite, could be effectively operated as electron donors by a neutrophilic chemoautotroph, Acidovorax in a batch bioreactor, and the intermediate microbial physiological constituents, VFAs, released from mineral bio-oxidation, could enable the shuttle of electrons to Cr(VI) involving a reducer like Geobacter . In an up-flow anaerobic sludge bed reactor, the population of genus Trichococcus greatly increased toward the operation period of Cr(VI) reduction using anaerobic sludge, which mainly attributed to fermentation of organic complexes to be available as electron donors, where genera like Desulfovibrio , Ochrobactrum , and Anaerovorax were the main Cr(VI) reducers ( Qian et al, 2017 ). Anaerobic digestion using various electron donors have shown high efficiency of Cr(VI) reduction in different bioreactors ( Wang et al, 2018 ; Zheng et al, 2019 ).…”

Section: Role Of Various Chemical Additives In Ex Situ mentioning

confidence: 99%

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

Rahman

Thomas

2021

Front. Microbiol.

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Chromium (Cr) (VI) is a well-known toxin to all types of biological organisms. Over the past few decades, many investigators have employed numerous bioprocesses to neutralize the toxic effects of Cr(VI). One of the main process for its treatment is bioreduction into Cr(III). Key to this process is the ability of microbial enzymes, which facilitate the transfer of electrons into the high valence state of the metal that acts as an electron acceptor. Many underlying previous efforts have stressed on the use of different external organic and inorganic substances as electron donors to promote Cr(VI) reduction process by different microorganisms. The use of various redox mediators enabled electron transport facility for extracellular Cr(VI) reduction and accelerated the reaction. Also, many chemicals have employed diverse roles to improve the Cr(VI) reduction process in different microorganisms. The application of aforementioned materials at the contaminated systems has offered a variety of influence on Cr(VI) bioremediation by altering microbial community structures and functions and redox environment. The collective insights suggest that the knowledge of appropriate implementation of suitable nutrients can strongly inspire the Cr(VI) reduction rate and efficiency. However, a comprehensive information on such substances and their roles and biochemical pathways in different microorganisms remains elusive. In this regard, our review sheds light on the contributions of various chemicals as electron donors, redox mediators, cofactors, etc., on microbial Cr(VI) reduction for enhanced treatment practices.

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Section: Role Of Various Chemical Additives In Ex Situ mentioning

confidence: 99%

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

Rahman

Thomas

2021

Front. Microbiol.

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“…Their corresponding percentages removal were 87.87% at 600 mg/m 3 .d, 94.22 % at 1800 mg/m 3 .d, 92.25 % at 3000 mg/m 3 .d and 98.47 % at 6000 mg/ m 3 .d. Results can be explained that reduction process induced by hexavalent chromium in the presence of biological sulfidogenesis was carried out by SBR (Desulfobacter, Desulfobulbus and Desulfovibrio) [15]. Figure 3 shows that the maximum Cr (VI) reduction rate was 3.95 mg Cr (VI)/L/h and this is in presence of mixed sludge culture formed from anaerobic sludge and the hydrogen sulfide produced in the H-UASB which stimulate the SBR to reduce Cr (VI) into Cr (III).…”

Section: Performance Of the H-uasb Inoculated With Different Concentrmentioning

confidence: 99%

“…In H-UASB, the pH ranges from 6.5-8.5 and Cr (VI) can exist as which is reduced directly to Cr (III) by SRB and chromate reducing bacteria using the organic matter as an electron donor and chrome hydroxide sediment is formed on the surface of the microorganisms as indicated in equation 4. Qian et al [15] showed that possesses similar bioactivity like because they have similar structure (four tetrahedrally arranged oxygen atoms and two negative charges).…”

Section: Fig 3 Removal Rate Of Cr (Vi) At Different Concentrationsmentioning

confidence: 99%

Bio-immobilization of Cr (VI) and its Impact on the Performance of a Pilot Scale Anaerobic Sludge Reactor Treating Municipal Wastewater

Abou‐Elela

Fawzy

El-Sorogy³

et al. 2018

Egypt. J. Chem.

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T HIS study aimed to emphasize the effect of hexavalent chromium Cr (VI) on the performance of a pilot scale hybrid up-flow anaerobic sludge blanket (H-UASB). The system was packed with non-woven polyester fabric (NWPF) and continuously fed with real municipal wastewater at a hydraulic retention time (HRT) 7.5 h and average organic loading rate (OLR) 1.24 Kg COD m 3 /d. The system achieved satisfactory removal rates for total suspended solids (TSS) (86.44 %), chemical oxygen demand (COD) (74.18 %) and biological oxygen demand (BOD 5) (84.8%) without the addition of Cr (VI). Results indicated that feeding the reactor with different concentrations of chromium ions ranged from 0.1-1.3 mg/l (i.e: 600 mg / m 3. d to 6000 mg / m 3. d) decreased the residual concentration of Cr (VI) in the final effluent to 0.019 mg/l, while the accumulation of chromium ion increased in the biobed (160 mg/kg) and in excess sludge (165.44 mg/kg). This was due to the biological reduction of Cr (VI) to Cr (III) by the action of sulphate and chromate reducing bacteria. Increasing the concentration of Cr (VI) up to 6000 mg / m 3. d reduce the biochemical reactions of the anaerobic microorganisms and consequently decrease the removal efficiency of TSS from 86.44% to 62.06, COD from 74.2 % to 57.07 % and BOD 5 from 84.8% to 61.92%.

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“…Recently, several researchers verified that mixed sludge that enriched microbial population could reduce chromium polluting potential, thus avoiding the high cost of strain cultivating [18][19][20]. These studies overcame the weaknesses of the poor adaptability of the single strain in the field environmental conditions [17].…”

Section: Introductionmentioning

confidence: 99%

External Carbon Source Facilitates Indirect Cr (VI) Bioreduction Process by Anaerobic Sludge Produced from Kitchen Waste

et al. 2021

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This study presented the investigation on indirect Cr (VI) bioreduction process by anaerobic sludge produced from kitchen waste (ASKW) using an external source of glucose and sulfate to favor the reducing environment. These compounds were added at the beginning of the experiment along with 500 mg·L−1 Cr (VI). The system containing 1 g of glucose and 2 g of sulfate attained a higher reduction, which was 10% higher than that of the control experiment. This study indicated that a neutral environment (pH ~7), along with a high release of polysaccharides (PS), improved the removal efficiency by Cr (VI) bioreduction process. Desulfovibrio and Sulfurospirillum (genus level), which accounted for 3% and 1% of the whole microorganism, respectively, were responsible for the sulfidogenic reaction. Additionally, Thermovirga (genus level) reduced from 14% to 11% and 10%. These microorganisms contributed to dominating the indirect Cr (VI) bioreduction process. SEM and FTIR analysis of the sludges obtaining from the indirect Cr (VI) bioreduction systems indicated that the external glucose could facilitate the formation of looser porous structures and richer functional groups of sludges, thus adsorbing more Cr (III) to reduce its toxicity. Meanwhile, the intensity of the hydroxyl bond, which possesses strong reducibility, was much higher after adding external glucose. Chromate reductase gene (chrR) and sulfite reductase gene (dsrA) contributed to the indirect Cr (VI) bioreduction process. These might be the main mechanisms of the external glucose acting on indirect Cr (VI) bioreduction by ASKW.

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Direct Cr (VI) bio-reduction with organics as electron donor by anaerobic sludge

Cited by 71 publications

References 31 publications

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

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

Bio-immobilization of Cr (VI) and its Impact on the Performance of a Pilot Scale Anaerobic Sludge Reactor Treating Municipal Wastewater

External Carbon Source Facilitates Indirect Cr (VI) Bioreduction Process by Anaerobic Sludge Produced from Kitchen Waste

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