Assessment of the heavy metal bioremediation efficiency of the novel marine lactic acid bacterium, Lactobacillus plantarum MF042018

Abstract

Heavy metal pollution is one of the most serious environmental and human health risk problem associated with industrial progress. The present study was conducted with the goal of isolation and characterization of metal-resistant lactic acid bacteria (LAB) from the Alexandrian Mediterranean Seacoast, Egypt, with their possible exploitation in metal remediation. Lactobacillus plantarum MF042018 exhibited high degree of resistance, up to 500 and 100 ppm, to both nickel and chromium, respectively, with multiple antibiotic resistance (MAR) index above 0.5. In an attempt to improve chromium removal by L. plantarum MF042018, Plackett-Burman followed by Box-Behnken statistical designs were applied. An initial Cr 2+ concentration of 100 ppm and inoculum size of 3% presented the best conditions for the accumulation of chromium by L. plantarum MF042018. The study was also navigated to assess the biosorption capacity of L. plantarum MF042018, the maximum uptake capacity (q) of both Cd 2+ and pb 2+ was recorded at pH 2.0 and a temperature of 22 °C after 1 hr. The biosorption process of Cd 2+ and pb 2+ was well explained by the Langmuir isotherm model better than the Freundlich isotherm. Furthermore, the results revealed that the use of L. plantarum MF042018 is an effective tool for the treatment of hazardous metal-polluted battery-manufacturing effluent. Therefore, the present study implies that L. plantarum MF042018 can be applied as a promising biosorbent for the removal of heavy metals from industrial wasterwaters. As a consequence of disastrous anthropogenic activities, the discharge of hazardous heavy metal pose devastating threat to environmental safety and subsequently lead to severe concerns on human health worldwide 1. Nowadays, several approaches have been successfully developed to use magnetic nanoparticles (MNPs), such as magnetic chitosan/graphene oxide (MCGO) composite, and ultrasonic irradiation for the synthesis of metal organic frameworks (MOFs) for the removal of heavy metals from contaminated environments 2,3. In this context, the expansion of new technologies has led to the evolution of "Bioremediation" as a powerful alternative tool to reduce the adverse consequences of the tremendous accumulation of heavy metals 4. Bioremediation; using bacteria, fungi, yeast and algae, is an efficient, cost-effective and environmentally friendly strategy that has recently received great attention to tackle heavy metal contamination 5. Recently, the use of microorganisms especially fungi as potential biosorbents for the removal of heavy metals from industrial wastewater effluents has been extensively investigated 6-8. Lactic acid bacteria (LAB) are Gram-positive bacteria, that have gained Generally Recognized As Safe (GRAS) status by the US Food and Drug Administration (FDA) and have a strong record of safe application as probiotic supplements 9. Recently, several strains of LAB have generated much attention to their potential use in the removal of heavy metals for protection of human health 10-13. A considerable number ...

Biological treatment of hazardous heavy metals by Streptomyces rochei ANH for sustainable water management in agriculture

“…Moreover, Ameen et al . 13 indicated that using the biosorbent packed in a dialysis tube effectively facilitates the collection of cells from the treated industrial effluent for further use.…”

“…To each well, 100 μl of the standard metal solution, at various concentrations (30–500 mg/l), was loaded and incubated at 30 °C for 7 days. The diameter of growth inhibition around each well was measured (in millimeters) and the Minimum Inhibitory Concentration (MIC) of each metal, that prevents visible growth of actinomycetes, was recorded 13 . The actinomycete isolate with the highest metal-resistance ability was selected for further studies.…”

“…However, conventional methods for treating toxic heavy metals in industrial wastewater are considered inefficient and relatively expensive 9 . Therefore, these shortcomings have led to the use of microorganisms, such as bacteria, yeast, algae, and fungi, in the bioremediation of heavy metals for the promotion of efficient, economically feasible, and eco-friendly alternative technology to mitigate heavy metal concentrations in industrial wastewater to environmentally acceptable levels 10 – 13 . Several studies have documented the efficient use of Escherichia coli , Neopestalotiopsis clavispora , Beauveria bassiana, and Metarhizium anisopliae as cost beneficial and efficient biosorbents for Pb 2+ , Zn 2+ , and Cd 2+ from aqueous solutions 14 – 16 (Table S1 ).…”

Assessment of Pb(II), Cd(II), and Al(III) Removal Capacity of Bacteria from Food and Gut Ecological Niches: Insights into Biodiversity to Limit Intestinal Biodisponibility of Toxic Metals

“…We first checked that our methods were reliable and appropriate for screening distinct bacterial strains for their ability to remove Pb, Cd, or Al. It is known that many factors influence the levels of metal binding by bacteria: the contact time, temperature, pH, metal ion concentration, washing buffer, and inoculum size [ 36 , 59 , 60 ]. Thus, several key parameters were defined to either mimic the gut environment or for reasons of convenience, e.g., the incubation temperature.…”

Assessment of Pb(II), Cd(II) and Al(III) Removal Capacity of Bacteria From Food and Gut Ecological Niches: Insights Into Biodiversity to Limit Intestinal Biodisponibility of Toxic Metals

“…We first ensured that our methods were reliable and appropriate enough to screen distinct bacterial strains for their ability to remove selected metals. It has been previously shown that many factors may influence the levels of metal binding by bacteria, such as contact time, temperature, pH, and salt concentration of metal solutions, as well as washing buffers and inoculum size [37,60,61]. Thus, several key parameters were defined to mimic the gut environment unless fixed for convenience, e.g.…”