Ferric citrate enhanced bioreduction of Cr(VI) by Bacillus cereus RCr in aqueous solutions: reduction performance and mechanisms.
Environ Sci Pollut Res Int
; 31(36): 48972-48985, 2024 Aug.
Article
em En
| MEDLINE
| ID: mdl-39042195
ABSTRACT
The bioreduction characteristics and mechanisms of Cr(VI) onto Bacillus cereus RCr enhanced by ferric citrate were investigated. The optimum conditions were initial pH 9, temperature 40 °C, inoculation amount 4%, and glucose 3 g/L, respectively. The addition of 1.5 g/L ferric citrate increased the average reduction rate from 120.43 to 220.61 mg/(Lâh) compared with the control (without ferric citrate). The binding capacity of Cr(III) on the cell surface increased to 21%, in which the precipitates were mainly CrO(OH), Cr2O3, and FeCr2O4. Cell membrane was the main site of reduction, related important functional groups - COOH, C-H, - NH2, C = C, and P-O. Fe(III) increased the yield of NADH and cytochrome c by approximately 48.51% and 68.63%, which significantly facilitated the electron generation and electron transfer, thus increasing the amount of electrons in the bioreduction of heavy metals by an average of 110%. Among the electrons obtained by Cr(VI), the proportion of indirect reduction mediated by Fe(III)/Fe(II) shuttle was 62% on average, whereas direct reduction mediated by reductase was 38%. These results may provide insights into the bioreduction process by bacteria enhanced by Fe(III) for detoxification of heavy metals with multiple valences, as an important step towards improving microbial remediation.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxirredução
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Bacillus cereus
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Compostos Férricos
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Cromo
Idioma:
En
Revista:
Environ Sci Pollut Res Int
Ano de publicação:
2024
Tipo de documento:
Article