Natural solution for the remediation of multi-metal contamination: application of natural amino acids, Pseudomonas fluorescens and Micrococcus yunnanensis to increase the phytoremediation efficiency

Abstract

Natural amino acids (NAA) have been rarely investigated as chelators, despite their ability to chelate heavy metals (HMs). In the present research, the effects of extracted natural amino acids, as a natural and environmentally friendly chelate agent and the inoculation of Pseudomonas fluorescens (PF) and Micrococcus yunnanensis (MY) bacteria were investigated on some responses of quinoa in a soil polluted with Pb, Ni, Cd, and Zn. Inoculation of PGPR bacteria enhanced plant growth and phytoremediation efficiency. Pb and Cd were higher in quinoa roots, while Ni and Zn were higher in the shoots. The highest efficiencies were observed with NAA treatment and simultaneous inoculation of PF and MY bacteria for Ni, Cd, Pb, and Zn. The highest values of phytoremediation efficiency and uptake efficiency of Ni, Cd, Pb, and Zn were 21.28, 19.11, 14.96 and 18.99 μg g−1, and 31.52, 60.78, 51.89, and 25.33 μg g−1, respectively. Results of present study well demonstrated NAA extracted from blood powder acted as strong chelate agent due to their diversity in size, solubilizing ability, abundant functional groups, and potential in the formation of stable complexes with Ni, Cd, Pb, and Zn, increasing metal availability in soil and improving phytoremediation efficiency in quinoa.

Graphical abstract

NOVELTY STATEMENT

This study focused on an underexplored topic, the potential of natural amino acids (NAA) and plant growth-promoting rhizobacteria (PGPRs) to enhance phytoremediation efficiency of quinoa in a multi-metal contaminated soil with the waste recycling approach. Despite their chelating abilities, NAA have been rarely studied in this context. In the present study, the effects of extracted NAA, acting as environmentally friendly chelating agents, and the inoculation of Pseudomonas fluorescens (PF) and Micrococcus yunnanensis (MY) bacteria were examined on the responses of quinoa in a soil contaminated with Pb, Ni, Cd, and Zn.

HIGHLIGHTS

Three agricultural wastes were used to prepare natural amino acids.

Natural amino acids caused satisfactory results in remediating HMs-polluted soil and amino acid extracted from blood powder gave the best results.

Phytoremediation efficiency depends strongly on the type of metal.

Pseudomonas fluorescens and Micrococcus yunnanensis improved remediation performance.

Keywords:

• Chelators
• heavy metals
• multi-metal contamination
• natural amino acids
• PGPRs
• phytoremediation

Acknowledgements

The authors would like to appreciate Shiraz University for providing facilities.

Authors’ contributions

Mehrnoosh Gol Soltani: writing the main manuscript text and prepared figures and tables.

Reza Ghasemi-Fasaei: designeing experiment project administrator. paper reviewing

Abdolmajid Ronaghi: Set up the methods and paper reviewing

Mehdi Zarei: Set up the methods and paper reviewing.

Sedigheh Zeinali: Set up the methods and paper reviewing.

Stefan B. Haderlein: Set up the methods and paper reviewing.

Disclosure statement

No potential conflict of interest was reported by the author(s). All authors have no competing interests as defined by Springer, or other interests that might be perceived to influence the results and/or discussion reported in this paper.

Data availability statement

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.