Jaafar 2020 - Pediococcus lead and cadmium bioremediation

Jaafar isolated a Pediococcus pentosaceus strain from common-carp pond water in Basra, Iraq, confirmed probiotic traits, and tested its tolerance and removal of experimentally added lead and cadmium. This is mitigation and bioremediation evidence, not consumer-product occurrence evidence: the Pb and Cd values come from spiked laboratory media and fish-pond remediation framing, so they should not enter food, salt, probiotic, or supplement benchmark pools.

Key numbers

The study collected nine water samples from three common-carp ponds during April 2018. Colonies grown on MRS agar were screened by Gram stain, catalase reaction, morphology, biochemical tests, and Vitek II; the selected isolate was identified as P. pentosaceus with 95% confidence.

For probiotic survival, Table 2 reports optical density at 600 nm across pH and bile-salt tests. At pH 3, OD600 declined from 0.564 after 3 hours to 0.327 after 24 hours; at pH 7, OD600 was 1.629 after 3 hours and 1.687 after 24 hours; at pH 9, OD600 was 1.511 after 3 hours and 1.645 after 24 hours. In bile salt, OD600 after 24 hours was 1.557 at 0%, 0.568 at 0.15%, 0.398 at 0.25%, and 0.239 at 0.5%. The gastric and intestinal juice test reported 390 bacteria at pH 3 after 24 hours and 205 bacteria at pH 8 after 24 hours.

For metal tolerance, the minimum inhibitory concentration was 1800 ppm for Pb and 150 ppm for Cd. The authors interpret this as stronger Pb resistance than Cd resistance in the isolated P. pentosaceus strain.

For metal removal, the study incubated bacteria in MRS broth containing 25 ppm or 50 ppm Pb or Cd for 24 hours at 37 C, centrifuged the cultures, and measured residual metal in the supernatant by flame atomic absorption spectrophotometry. Table 3 and the results text report:

The direction differs by metal: Pb removal increased from 25 ppm to 50 ppm, while Cd fractional removal decreased sharply at 50 ppm.

Methods (brief)

Water samples from carp ponds were serially diluted, plated on MRS agar, incubated at 37 C for 48 hours, and purified. The isolate was characterized by colony morphology, Gram reaction, catalase and biochemical testing, and Vitek II. Probiotic suitability was tested by acid tolerance, bile-salt tolerance, gastric and intestinal juice survival, antimicrobial activity against Salmonella sp., and antibiotic susceptibility.

For the bioremediation assay, Pb(NO3)2 and Cd(NO3)2.H2O were used to prepare spiked metal solutions. MIC testing used MRS agar supplemented with 25, 50, 100, 250, 500, 1000, 1500, 1800, and 2000 ppm Pb or Cd. Removal testing used 25 and 50 ppm Pb or Cd in MRS broth, 24-hour incubation at 37 C, centrifugation, and flame AAS (AAS 6300, Shimadzu, Japan) of the supernatant. The study reports removal percentages rather than sample-level pond-water Pb or Cd occurrence concentrations.

Implications

Certification: Do not use the Pb or Cd removal percentages as occurrence values for salt, probiotics, supplements, fish, pond water, or any HMTc product row. They are spiked-media mitigation endpoints.

Courses: Useful for explaining microbial biosorption and the firewall between remediation data and occurrence-threshold evidence. The contrasting Pb and Cd patterns are a compact example of why percent removal depends on metal species, concentration, organism, and assay medium.

App: Context only for mitigation education. The paper does not support consumer-facing claims that P. pentosaceus products remove Pb or Cd in humans or reduce metals in marketed foods.

Wiki pages this source may touch

• remediation-evidence
• formulation
• lead
• cadmium
• index

Verification notes

The auto-fetch filename framed this as salt/cadmium, but the PDF itself is a probiotic bioremediation paper. Products and ingredients are intentionally empty because no marketed salt, probiotic supplement, food ingredient, fish product, or consumer product was measured. The sample_n field records the nine pond-water samples used to isolate the bacterium; the metal-removal numbers are laboratory spiked-media assays.

The abstract reports Pb removal of 62.10-68.39% at 25 and 50 ppm, and Cd removal of 52.71-11.25% at the same concentrations. The results text clarifies the paired values: Pb was 62.10% at 25 ppm and 68.39% at 50 ppm; Cd was 52.71% at 25 ppm and 11.25% at 50 ppm. Those pairings are used above.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.