Microbial Pb(II)-bioprecipitation: Characterising responsible biotransformation mechanisms

Cilliers, Carla; Neveling, Olga; Tichapondwa, Shepherd Masimba; Chirwa, Evans M.N.; Brink, Hendrik Gideon

doi:10.1016/j.jclepro.2022.133973

Cited by 4 publications

(3 citation statements)

References 29 publications

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“…The points discussed above relate to the mechanisms of precipitation utilised by the bacteria. These observations coincide with the published work by this research team on the mechanisms of precipitation where the effect of nitrates was investigated [ 20 ]. The results indicated that the usage of nitrates by the bacteria was most prominent at lower concentrations of Pb(II) and that denitrifiers present in the consortium were most likely not responsible for Pb(II) removal.…”

Section: Resultssupporting

confidence: 91%

“…The initial drop in Pb(II) concentration could be indicative of a rapid detoxification mechanism (likely biosorption) since a drop in Pb(II) concentration is observed followed by an increase in Pb(II) concentration. The same occurrence was noted in previous research on the microbial consortium [ 16 , 20 ]. This is supported by previous research in which a drop of approximately 50% of Pb(II) concentration is observed after approximately 15 min using metabolically inactive biomass from the same consortium, therefore confirming the influence of biosorption [ 17 ].…”

Section: Resultssupporting

confidence: 88%

“…In a previous study on the effects of nitrate concentration on microbial precipitation of Pb(II) using the microbial consortium from which the strains used in this study were isolated, it was concluded that the lack of nitrates in the sample has no significant effect on the bioprecipitation rate of Pb(II) in the sample [ 20 ]. It is argued that the denitrification bacteria present in the consortium and therefore responsible for the drop in nitrate concentration observed for the microbial consortium in Figure 8 are not responsible for the bioprecipitation of lead [ 20 ].…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Microbial Precipitation of Pb(II) with Wild Strains of Paraclostridium bifermentans and Klebsiella pneumoniae Isolated from an Industrially Obtained Microbial Consortium

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et al. 2022

IJMS

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The study focused on determining the microbial precipitation abilities of bacterial strains that were isolated from an industrially obtained Pb(II)-resistant microbial consortium. Previous research has demonstrated the effectiveness of the consortium on the bioprecipitation and adsorption of Pb(II) from solution. The bioremediation of Pb(II) using microbial precipitation provides an alternative option for Pb(II) removal from wastewater. Both strains, Klebsiella pneumoniae and Paraclostridium bifermentans, were successfully isolated from the consortium obtained from a battery recycling plant in South Africa. The experiments were conducted over both 30 h and 5 d, providing insight into the short- and long-term precipitation abilities of the bacteria. Various initial concentrations of Pb(II) were investigated, and it was found that P. bifermentans was able to remove 83.8% of Pb(II) from solution with an initial Pb(II) concentration of 80 mg L−1, while K. pneumoniae was able to remove 100% of Pb(II) with the same initial Pb(II) concentration after approximately 5 d. With the same initial Pb(II) concentration, P. bifermentans was able to remove 86.1% of Pb(II) from solution, and K. pneumoniae was able to remove 91.1% of Pb(II) from solution after 30 h. The identities of the precipitates obtained for each strain vary, with PbS and Pb0 being the main species precipitated by P. bifermentans and PbO with either PbCl or Pb3(PO4)2 precipitated by K. pneumoniae. Various factors were investigated in each experiment, such as metabolic activity, nitrate concentration, residual Pb(II) concentration, extracellular and intracellular Pb(II) concentration and the precipitate identity. These factors provide a greater understanding of the mechanisms utilised by the bacteria in the bioprecipitation and adsorption of Pb(II). These results can be used as a step towards applying the process on an industrial scale.

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 88%