Nickel Solubilization Research Articles

Deciphering endemic rhizosphere microbiome community’s structure towards the host-derived heavy metals tolerance and plant growth promotion functions in serpentine geo-ecosystem

Environmental microbes in rhizosphere soil and surrounding plants have the potential to alter ecosystem functions. We investigated the microbial communities inhabiting the rhizosphere soils of both serpentine and non-serpentine rhizosphere zones to evaluate their heavy metal tolerance and ability to promote plant growth, utilizing 16S rRNA metabarcoding. The Biolog-EcoPlate technique was employed to determine how abiotic stress factors affect carbon utilization capacity by rhizospheric microbial communities in the serpentine geo-ecosystem. The phyla Proteobacteria, Acidobacteria, Bacteroidetes, and Nitrospirae colonized in the roots of Miscanthus sp., Biden sp., and Oryza sp. showed noticeable differences in different rhizosphere zones. The PICRUSt2-based analysis identified chromium/iron resistance genes (ceuE, chrA) and arsenic resistance genes (arsR, acr3, arsC) abundant in all the studied rhizosphere soils. Notably, nickel resistance genes (nikA, nikD, nikE, and nikR) from Arthrobacter, Microbacterium, and Streptomyces strongly correlate with functions related to solubilization of nickel and an increase in siderophore and IAA production. The abundance of Arthrobacter, Clostridium, Geobacter, Dechloromonas, Pseudomonas, and Flavobacterium was positively correlated with chromium and nickel but negatively correlated with the calcium/magnesium ratio. Our results contribute to a better understanding of the functions of plant-tolerant PGPR interaction in the heavy metal-contaminated rhizosphere and eco-physiological responses from long-term biological weathering.

Bioleaching of low grade nickel ore using indigenous fungi

In this research, the biological leaching of nickel by indigenous fungi isolated from Indonesian limonite was studied to develop a feasible technique for microbial recovery of nickel from low grade nickel ore. XRD analyses indicated that goethite, alumina and quartz were major mineral composition of the ore. In the present study, isolated fungal strains having potential to solubilize nickel were characterized. that were identified as Aspergillus sp and Penicillium sp depending upon their colony morphology and microscopic studies. All microorganisms found were tested for organic acid production and leaching capabilities of nickel. Leaching experiments were performed in 250 ml Erlenmeyer flask at room temperature and 150 rpm agitation under aseptic conditions. It was observed that the Aspergillus sp substantially leached more nickel from limonite compared to the Penicillium sp . Nickel solubilization was related to pH decrease and organic acid excreted caused by growth of fungi in medium containing glucose as carbon source. The mechanisms of nickel extraction had been examined either directly or indirectly related to fungal activity. The presence of fungal cells seems to improve the leaching process. However, the use of higher pulp density resulted in a decrease of nickel solubilization. The maximum nickel recovery was 57% at 5% pulp density after 20 days of direct leaching by Aspergillus sp .

Fungal Bioleaching of Metals From Mine Tailing

The present study was undertaken to develop an economically feasible and environmental-friendly technique to recover metals (Ni, Cu, Co, Zn, Mg) from mine tailing by employing Penicillium chrysogenum strain KBS3. The potential of Penicillium chrysogenum in generating a variety of organic acids was studied and the effect of different organic wastes as substrates was evaluated. Maximum solubilization of nickel (55%), copper (67%), magnesium (69%), cobalt (60%), and zinc (65%) was achieved in the media containing glucose, tea leaves, molasses, and waste winery grapes as substrates.

Compositions of microbial communities in sulfide nickel ore waste piles

Bacterial communities of moderately acidic waste piles of sulfide nickel ore and of the nickel-leaching enrichments obtained from them are analyzed. The structure of bacterial communities was determined by molecular biological techniques. The PCR profiles of bacterial communities were obtained with the primers to a variable 433 bp site of the eubacterial 16S rRNA gene. The differences in community compositions were determined by comparison of their DGGE profiles. Sequencing of the DNA fragments was then carried out and the results were compared with the GenBank gene sequences. Analysis of the 16S rRNA gene sequences revealed few bacterial genera in the moderately acidic waste piles of sulfide nickel ore, with predomination of Acidithiobacillus sp. and Leptospirillum sp. A number of the bacteria revealed belonged to the species never obtained in pure culture. Molecular biological analysis showed the presence of the same groups of bacteria in enriched cultures obtained by inoculating the liquid medium containing ground ore with the waste pile samples (5 : 1). The geochemical activity of these bacteria was confirmed by their capacity for leaching nickel from the sulfide ore in enriched cultures, resulting in nickel solubilization. Thus, new information was obtained concerning the structure composition of the bacterial communities of sulfide ore waste piles: the dominant forms were determined, their leaching activity was confirmed, and the activity of thiobacilli from the waste, which have not been isolated in pure cultures, was confirmed in liquid medium in the presence of ore.

Microbial extraction of nickel from Sukinda chromite overburden by Acidithiobacillus ferrooxidans and Aspergillus strains

In this study, the recovery of nickel from a low-grade chromite overburden was attempted by employing two fungal strains, Aspergillus niger and Aspergillus fumigatus, and a mixed culture of mesophilic acidophiles (predominantly Acidithiobacillus ferrooxidans). Various factors were studied for bioleaching of chromite overburden such as, temperature, pH and pulp density. It was found that the At. ferrooxidans culture solubilized nickel effectively at temperatures ranging from 30 °C to 37 °C, whereas the organism was not able to solubilize nickel at higher temperatures, such as 45 °C. The use of higher pulp density resulted in a decrease of the percent nickel recovery whereas lower pulp density resulted in higher recovery values. Besides, increased supplemental ferrous iron increased the leaching efficiency of the At. ferrooxidans culture. The maximum nickel solubilization was 40%, at 2% pulp density, and 24%, at 10% pulp density, at 30 °C after 28 days leaching at 150 rpm. In the case of fungal strains, a comparison of leach ability of chromite overburden and roasted overburden was made. The factors studied were pulp density and reaction time. The adapted fungal strain showed better leaching results as compared to the unadapted strains. The in situ nickel leaching efficiency of a laboratory stock culture of A. niger showed maximum recovery of 34% nickel with roasted chromite overburden, at 2% pulp density, while 32% nickel was solubilized by A. fumigatus, under the same conditions at 30 °C and 150 rpm, after 28 days incubation.

The solubilization of nickel, cobalt and iron from laterites by means of organic chelating acids at low pH

An economical process for recovering nickel from large quantities of low grade laterite is needed. With this in mind heterotrophic microbial leaching was investigated as an alternative to the energy expensive existing extraction process. Organic acids were screened for the ability to solubilize nickel, iron and cobalt from laterite ores and the results compared with sulphuric acid treatment of limonite type laterite at pH 2.3 and 28°C which solubilized nickel, cobalt and iron. Citric, tartaric and pyruvic acids significantly increased the yield of soluble nickel extracted at pH 2.3 with sulphuric acid. Despite their reported efficacy for other mineral systems, lactic, glycollic and oxalic acids were not effective solubilizers of nickel from Indonesian laterite and 2-ketogluconic, lactic and glycollic acids did not effectively solubilize nickel from West Australian laterite. Metabolites generated from glucose by the natural flora of limonite type laterite ore were associated with significant solubilization of metals from the ore at acid pH due to their chelating activities. The leaching solutions generated from glucose retained activity when recycled, an important consideration if the solution is to have industrial application. The leach liquors from these studies were analyzed for the extent of metal extraction and the presence of microbially produced metal chelators. Cellulose acetate electrophoresis provided proof that chelated nickel complexes were present amongst nickel ions solubilized at acid pH by metabolites of glucose generated by the natural flora of the ore. This technique also provided proof that citric acid functions as a chelator of divalent metal cations at strongly acid pH, a point hitherto the subject of conflicting reports in the literature. Atomic absorption spectrometry and X-ray diffraction studies confirmed the findings from cellulose acetate electrophoresis.

Bacteriology of manganese nodules. VI. Fate of copper, nickel, cobalt, and iron during bacterial and chemical reduction of the manganese (IV)

AbstractCopper, nickel, and cobalt entered into seawater solution while the manganese (IV) oxide matrix of marine ferromanganese nodules to which they were bound was being reduced by glucose in the presence of peptone. Negligible amounts of iron were solubilized under similar conditions. Bacillus GJ 33 significantly accelerated the reduction and solubilization of manganese (IV) oxide by chemical means and thereby also accelerated the solubilization of nickel and cobalt, and, in advanced stages, of copper. Nickel and cobalt solubilization were directly dependent on manganese (IV) oxide reduction and solubilization while copper solubilization was only partly dependent on it. Some copper in the ferromanganese nodule substance was solubilized as a result of complexing by peptone without concurrent manganese (IV) oxide reduction. The release of manganese, copper, or nickel (cobalt was not tested) could not be attributed to acid formation during glucose oxidation by manganese (IV) oxide regardless of whether the reaction was purely chemical or catalyzed by bacteria. These findings suggest that nickel and cobalt are more tightly bound to the manganese (IV) oxide matrix than copper. An adsorption experiment showed that manganese, copper and nickel could originally have entered the nodule matrix by adsorption.