Bio-recovery of non-essential heavy metals by intra- and extracellular mechanisms in free-living microorganisms

García‐García, Jorge Donato; Sánchez‐Thomas, Rosina; Moreno‐Sánchez, Rafael

doi:10.1016/j.biotechadv.2016.05.003

Cited by 103 publications

(29 citation statements)

References 197 publications

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“…Bioaccumulation and biosorption are two main resistance mechanisms against metal(loid)s used by microalgae and other biological systems, although there are also other well-characterized protection mechanisms [52,81]. Our micrographs indicate that both means of cation immobilization have been involved in the resistance to Cd and As.…”

Section: Analysis Of Mechanisms Involved In Tolerancementioning

confidence: 73%

“…The chemical nature of these deposits was verified by TEM-XEDS. In some microalgae, data indicate that Cd bioaccumulation might be mainly mediated by the tripeptide GSH and its polymeric derivatives, known as phytochelatins [81,82]. There is little experimental evidence of As bioaccumulation in microalgae mediated by phytochelatins [56,59,83], although in higher plants, the participation of these peptides in As accumulation has been corroborated [84].…”

Section: Analysis Of Mechanisms Involved In Tolerancementioning

confidence: 99%

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Toxicity, Physiological, and Ultrastructural Effects of Arsenic and Cadmium on the Extremophilic Microalga Chlamydomonas acidophila

Díaz

Francisco

Olsson³

et al. 2020

IJERPH

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The cytotoxicity of cadmium (Cd), arsenate (As(V)), and arsenite (As(III)) on a strain of Chlamydomonas acidophila, isolated from the Rio Tinto, an acidic environment containing high metal(l)oid concentrations, was analyzed. We used a broad array of methods to produce complementary information: cell viability and reactive oxygen species (ROS) generation measures, ultrastructural observations, transmission electron microscopy energy dispersive x-ray microanalysis (TEM-XEDS), and gene expression. This acidophilic microorganism was affected differently by the tested metal/metalloid: It showed high resistance to arsenic while Cd was the most toxic heavy metal, showing an LC 50 = 1.94 µM. Arsenite was almost four-fold more toxic (LC 50 = 10.91 mM) than arsenate (LC 50 = 41.63 mM). Assessment of ROS generation indicated that both arsenic oxidation states generate superoxide anions. Ultrastructural analysis of exposed cells revealed that stigma, chloroplast, nucleus, and mitochondria were the main toxicity targets. Intense vacuolization and accumulation of energy reserves (starch deposits and lipid droplets) were observed after treatments. Electron-dense intracellular nanoparticle-like formation appeared in two cellular locations: inside cytoplasmic vacuoles and entrapped into the capsule, around each cell. The chemical nature (Cd or As) of these intracellular deposits was confirmed by TEM-XEDS. Additionally, they also contained an unexpected high content in phosphorous, which might support an essential role of poly-phosphates in metal resistance. development of phytoplankton [5][6][7]. However, most of these studies are related to circumneutral pH water environments polluted by industrial and domestic wastes, in spite of the fact that pH has a considerable effect on the availability and, as a consequence, the toxicity of heavy metals [8].Indeed, many freshwater bodies worldwide are highly acidic (pH < 3), either due to natural causes or anthropogenic activities such as mining [9,10]. Acid drainages are due mainly to pyrite oxidation, producing significant acidity in lakes and ponds situated in areas impacted by mining, as well as in rivers receiving mine water discharge [11,12]. Additionally, extreme acidic environments tend to contain unusually high concentrations of heavy metals because their solubility increases markedly as the pH decreases [11]. Despite these extreme environmental conditions, a number of prokaryotic and eukaryotic organisms living in these extreme environments have been identified [13]. Microalgae are the dominant eukaryotes found in these ecosystems, green microalgae such as Chlamydomonas, Dunaliella, and Chlorella being the main primary producers [13].Although acidophilic algae are able to grow at high heavy metal concentrations and low pH, both of which are lethal to most eukaryotes [14], the adaptive mechanisms by which these microorganisms can survive under such environmental conditions are still poorly understood. Proteomic analysis has pointed out the importance of metal and acidity toleranc...

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Section: Analysis Of Mechanisms Involved In Tolerancementioning

confidence: 73%

Section: Analysis Of Mechanisms Involved In Tolerancementioning

confidence: 99%

Toxicity, Physiological, and Ultrastructural Effects of Arsenic and Cadmium on the Extremophilic Microalga Chlamydomonas acidophila

Díaz

Francisco

Olsson³

et al. 2020

IJERPH

View full text Add to dashboard Cite

show abstract

“…However, even if the content is relatively low, long-term drinking will accumulate in the body, causing poisoning. The question of how to remove heavy metal ions in wastewater effectively and at the same time realize the wastewater reuse and recycling of heavy metals is the development direction of heavy metal wastewater treatment [88,89]. Microbial flocculant, as a green flocculant, is also applied to the process of flocculation of heavy metal wastewater [62,[90][91][92].…”

Section: Heavy Metal Wastewater Treatmentmentioning

confidence: 99%

Preparation, Performances, and Mechanisms of Microbial Flocculants for Wastewater Treatment

et al. 2020

IJERPH

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In recent years, close attention has been paid to microbial flocculants because of their advantages, including safety to humans, environmental friendliness, and acceptable removal performances. In this review, the preparation methods of microbial flocculants were first reviewed. Then, the performances of bioflocculants in the removal of suspended solids, heavy metals, and other organic pollutants from various types of wastewater were described and commented, and the removal mechanisms, including adsorption bridging, charge neutralization, chemical reactions, and charge neutrality, were also discussed. The future research needs on microbial flocculants were also proposed. This review would lead to a better understanding of current status, challenges, and corresponding strategies on microbial flocculants and bioflocculation in wastewater treatment.

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“…Both biosorption and bioaccumulation have challenges that limit their use for HMR, but they arise differently and require distinct approaches to address them (Chojnacka, 2010 ; García-García et al, 2016 ; Hansda et al, 2016 ). Solutions for biosorption are often inspired from solutions for conventional sorption-based methods: extensive screening of microbial species with attractive adsorption properties, chemical modification of the anionic moieties on the outer surface, and the genetic engineering of the extracellular space to have metal-binding proteins and peptides (Rangabhashiyam et al, 2014 ; Ueda, 2016 ; Ayangbenro and Babalola, 2017 ).…”

Section: Biosorption or Bioaccumulation?mentioning

confidence: 99%

Heavy Metal Removal by Bioaccumulation Using Genetically Engineered Microorganisms

Diep

Mahadevan

Yakunin

2018

Front. Bioeng. Biotechnol.

244

100

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Wastewater effluents from mines and metal refineries are often contaminated with heavy metal ions, so they pose hazards to human and environmental health. Conventional technologies to remove heavy metal ions are well-established, but the most popular methods have drawbacks: chemical precipitation generates sludge waste, and activated carbon and ion exchange resins are made from unsustainable non-renewable resources. Using microbial biomass as the platform for heavy metal ion removal is an alternative method. Specifically, bioaccumulation is a natural biological phenomenon where microorganisms use proteins to uptake and sequester metal ions in the intracellular space to utilize in cellular processes (e.g., enzyme catalysis, signaling, stabilizing charges on biomolecules). Recombinant expression of these import-storage systems in genetically engineered microorganisms allows for enhanced uptake and sequestration of heavy metal ions. This has been studied for over two decades for bioremediative applications, but successful translation to industrial-scale processes is virtually non-existent. Meanwhile, demands for metal resources are increasing while discovery rates to supply primary grade ores are not. This review re-thinks how bioaccumulation can be used and proposes that it can be developed for bioextractive applications—the removal and recovery of heavy metal ions for downstream purification and refining, rather than disposal. This review consolidates previously tested import-storage systems into a biochemical framework and highlights efforts to overcome obstacles that limit industrial feasibility, thereby identifying gaps in knowledge and potential avenues of research in bioaccumulation.

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Bio-recovery of non-essential heavy metals by intra- and extracellular mechanisms in free-living microorganisms

Cited by 103 publications

References 197 publications

Toxicity, Physiological, and Ultrastructural Effects of Arsenic and Cadmium on the Extremophilic Microalga Chlamydomonas acidophila

Toxicity, Physiological, and Ultrastructural Effects of Arsenic and Cadmium on the Extremophilic Microalga Chlamydomonas acidophila

Preparation, Performances, and Mechanisms of Microbial Flocculants for Wastewater Treatment

Heavy Metal Removal by Bioaccumulation Using Genetically Engineered Microorganisms

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