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

Abstract

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.

Populational genomic insights of Paraclostridium bifermentans as an emerging human pathogen

“…The versatility of P.b can be attributed to its adaptive capacity and genomic plasticity, which is primarily determined by the accessory genome. For instance, P.b strains have been utilized in various applications such as metal-contamination bioremediation (Neveling et al, 2022), antibiotic degradation (Fang et al, 2021) and organic compound conversion (Huang et al, 2022). In contrast, P.s strains, those that had genomes sequenced were all isolated from animal or human hosts (Figure 1A) and are commonly involved in infections (Zerrouki et al, 2021;Gonzalez-Astudillo et al, 2022), indicating that they may have adapted to these environments by encoding more host defense functions (Figure 3D).…”

Comparative Screening Study on the Adsorption of Aqueous Pb(II) Using Different Metabolically Inhibited Bacterial Cultures from Industry

“…Klebsiella pneumoniae (KP) and Paraclostridium bifermentans (PB) were identified using 16S rDNA sequencing as microbial strains present in Cons and were found likely to be the main organisms responsible for the bioprecipitation of lead [12]. The preparation of PB and KP is described by Neveling et al [13].…”