Assessment of In Vitro and In Vivo Bioremediation Potentials of Orally Supplemented Free and Microencapsulated Lactobacillus acidophilus KLDS Strains to Mitigate the Chronic Lead Toxicity

Overview

Key numbers

In vitro lead (Pb) binding

Table 2 reports Pb removal from 100 mg/L Pb nitrate solution by wet bacterial biomass and minimum inhibitory concentration for six L. acidophilus KLDS strains. Values are mean +/- SD of three determinations for MIC; different letters indicate p < 0.05.

Table 3 reports Langmuir and Freundlich isotherm constants for Pb binding by L. acidophilus KLDS 1.1003 biomass. The Langmuir model reported qmax = 6.1124 mg metal/g biosorbent, KL = 0.3204, RL = 0.0587, and R2 = 0.9052. The Freundlich model reported 1/n = 1.4118, Kf = 25.8134, and R2 = 0.9842.

Mouse Pb body burden

Table 1 describes six mouse groups, n = 10 each. Pb-exposed groups received lead nitrate at 100 mg/L in drinking water for 7 weeks. Treatment groups received free or MRS-based encapsulated L. acidophilus KLDS 1.1003 in skimmed milk by daily gavage; the text gives 1.3 x 10^9 CFU in the methods and the table note gives 1.4 x 10^9 CFU.

Figure 6 and the surrounding results text report that Pb-only mice had 142.5 +/- 5.817 ug/L Pb in blood. Free L. acidophilus KLDS 1.1003 plus Pb reduced blood Pb to 127.92 +/- 5.220 ug/L, and MRS-encapsulated L. acidophilus KLDS 1.1003 plus Pb reduced blood Pb to 101.47 +/- 4.142 ug/L.

For tissue Pb, the Pb-only group had 21.36 +/- 0.872 ug/g in liver and 23.13 +/- 0.944 ug/g in kidney. Free L. acidophilus KLDS 1.1003 plus Pb reduced liver Pb to 7.27 +/- 0.296 ug/g and kidney Pb to 19.86 +/- 0.810 ug/g. MRS-encapsulated L. acidophilus KLDS 1.1003 plus Pb reduced liver Pb to 6.42 +/- 0.262 ug/g and kidney Pb to 18.02 +/- 0.735 ug/g.

Essential element shifts

Table 4 reports Zn, Ca, Mg, and Fe in mouse liver and kidney after the same 7-week exposure. In liver, the Pb-only group had Ca 241.70 +/- 1.33, Mg 209.22 +/- 2.26, and Fe 34.04 +/- 1.72, while the MRS-encapsulated L. acidophilus plus Pb group had Ca 303.09 +/- 1.52, Mg 237.31 +/- 2.02, and Fe 46.94 +/- 2.34. In kidney, the Pb-only group had Zn 22.32 +/- 1.11, Ca 824.27 +/- 3.09, Mg 202.62 +/- 0.03, and Fe 48.29 +/- 2.41, while the MRS-encapsulated L. acidophilus plus Pb group had Zn 20.93 +/- 1.04, Ca 837.26 +/- 3.23, Mg 204.21 +/- 1.04, and Fe 54.87 +/- 2.74. The table does not state a unit in the extracted text, so these values are retained only as source-reported tissue element values, not converted product concentrations.

Methods (brief)

Six L. acidophilus KLDS strains were screened for Pb tolerance and wet-biomass Pb removal after incubation with Pb nitrate. The selected strain, L. acidophilus KLDS 1.1003, was also tested in maize-resistant-starch microencapsulated form; SEM/EDS and FTIR were used to characterize Pb binding on bacterial and encapsulated biomass surfaces. For the animal model, adult female BALB/c mice were divided into six groups of ten and exposed for 7 weeks to plain water or 100 mg/L Pb nitrate in drinking water, with or without daily gavage of free or MRS-encapsulated L. acidophilus in skimmed milk. Pb in blood was measured using a BH 2100 kit; liver and kidney samples were nitric-acid digested and measured by flame atomic absorption spectrophotometry. The reported Pb values are blood and tissue body-burden endpoints from a spiked animal model, not food, supplement, or ingredient occurrence values.

Related evidence

• Formulation mitigation
• Remediation evidence — drivers and interventions
• Lead
• Zinc
• Iron
• Magnesium
• Testing

Update history

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