Metallophores production by bacteria isolated from heavy metal-contaminated soil and sediment at Lerma–Chapala Basin

Abstract

Environmental pollution derived from heavy metals (HMs) is a worldwide problem and the implementation of eco-friendly technologies for remediation of the pollution are necessary. The metallophores are low-molecular weight compounds that have important biotechnological applications in agriculture, medicine and biorremediation. The aim of this work was to isolate the HM resistant bacteria from soils and sediments of Lerma-Chapala basin, and to evaluate their abilities to produce metallophores and to promote plant growth. A total of 320 bacteria were recovered, and the siderophores synthesis was detected in cultures of 170 of the total isolates. The Lerma-Chapala Basin bacteria also produced metallophores for all the tested metal ions and presented a greater production of As 3+ metallophores. The members in genera Delftia and Pseudomonas showed siderophores production above 92 percent siderophore units (psu). In addition, the hydroxamate was the most common fuctional group among the analyzed siderophores. Also, the bacteria showed high HM resistance especially to Zn 2+ , As 5+ and Ni 2+ . Our results evidenced that Lerma-Chapala basin bacteria or their metallophores could be employed in biorremediation process or may even have potential for applications in other biotechnological purposes.

Diversity and Biotechnological Potential of Cultivable Halophilic and Halotolerant Bacteria from the “Los Negritos” Geothermal Area

“…To isolate halophilic and/or halotolerant microorganisms from the soil samples, two strategies were applied. The first method, an enrichment protocol [ 13 ], was performed using SP or halophilic medium (HM) broth [ 14 ] supplemented with 10% and 22% NaCl ( w / v ), respectively. The enrichment of halophilic and halotolerant bacteria was performed by transferring 1 g of soil from each composite soil sample to flasks containing 20 mL of SP or HM broth and incubating them at room temperature (28 °C ± 2 °C) for 7 days at 150 rpm.…”

Mycobiota of Mexican Maize Landraces with Auxin-Producing Yeasts That Improve Plant Growth and Root Development

“…Siderophore production was induced by inoculating 1 × 10 8 yeast cells/mL in 5 mL of Iron deferrated Grimm-Allen liquid media [ 72 ] and incubating this at 28 °C for 15 days at 120 rpm. The cultures were centrifuged, and 100 µL of the supernatant was mixed with 100 µL of chrome azurol S (CAS)-Fe solution and 2 μL of shuttle solution (0.2 M 5-sulfosalicylic acid) [ 73 ]. The reaction mixture was incubated in the dark at room temperature for 10 min and then read at 630 nm on a VersaMax™ Tunable Microplate Reader.…”

Unveiling the Pool of Metallophores in Native Environments and Correlation with Their Potential Producers

“…3−6 The former has great repercussions, e.g., in agriculture, making the metals more available to the plant promoting its growth, 7 whereas the latter has great impact in environmental bioremediation. 8,9 In conditions of metal scarcity, the production of metallophores by some microorganisms could participate in shaping microbial communities by promoting both cooperative and competitive interactions. 10,11 Among metallophores, the best-known and studied are those that complex iron, also known as side-rophores.…”

“…Metallophores are organic ligands produced by bacteria, fungi, and plants that scavenge metals from the environment (terrestrial and marine) creating a soluble complex. , They play a pivotal role in metal homeostasis, making the metal available to the cell, or contributing to the mitigation of toxic metal contamination from the environment. − The former has great repercussions, e.g., in agriculture, making the metals more available to the plant promoting its growth, whereas the latter has great impact in environmental bioremediation. , In conditions of metal scarcity, the production of metallophores by some microorganisms could participate in shaping microbial communities by promoting both cooperative and competitive interactions. , Among metallophores, the best-known and studied are those that complex iron, also known as siderophores. , Siderophores produced by bacteria and fungi that thrive at neutral pH (ideal conditions for binding) are well characterized, with hundreds of them identified, mostly using laboratory incubation cultures. , However, in the case of soils and environments rich in organic matter, iron availability is constricted, becoming growth limiting. The limited recovery of siderophores from the environment as well as the alkalinity and complexity of the matrix makes the identification of siderophores (and other metallophores by extension) in these highly challenging environments …”