Hexavalent Chromium (VI) Removal by Aspergillus niger

Biosorption of Heavy Metals by Candida albicans

“…If we incubate the fungal biomass without a carbon source, there are no changes in the initial Cr(VI) concentration during the experiment (data not shown), suggesting that a carbon source is required to decrease Cr(VI) concentration in the growth medium. Our studies are similar with those reported for Aspergillus niger [47], in which the reduction of Cr(VI) is higher when the medium contains fermentable carbon sources (100% glucose, 97.2% sucrose, and 93.35% citrate), and removal is high with oxidizable carbon source (89.9% glycerol), unlike the [47], with Penicillium lilacinum using chromate-resistant strains of filamentous fungi indigenously [48], for Aspergillus foetidus [49], and the strain Ed8 of A. niger chromium resistant, all with glucose as the carbon source [50], but are different from the observations with Aspergillus sp., for which the observation was that sodium acetate was the carbon source that induced a greater removal of Cr(VI) [51].…”

“…In an experiment conducted in the absence of the yeast, the concentration of Cr(VI) of the samples decreased by about 14% in earth and 6% in water (data not shown), which may be caused by native microflora and reducers present in contaminated samples or components. The removal capacity of Cr(VI) by the fungus is equal or better than that for other yeasts reported such as C. maltose RR1 [19], with the removal of Cr(VI) by C. tropicalis [29]; the strains P. jadinii M9 and P. anomala M10, for Cr(VI) reduction [33]; for contaminated soil for bioremediation of Cr (VI) [45]; for Aspergillus niger [47]; and different yeasts [52].…”

Bioremoval of Different Heavy Metals by the Resistant Fungal StrainAspergillus niger

“…This indicates that these fungi developed the heavy metal tolerance and/or resistance, and they were identified by their macroscopic and microscopic characteristics [ 26 ]. In a previous study, it has been reported that the fungus grew in 2000 mg/L (42 µ g of dry weight) of chromium (VI), and it presents very good adsorption capacity of chromium (VI) in different conditions [ 17 ]. Also, the strain grew on LMM supplemented with different concentrations of heavy metals, about 37.6%, 24.6%, and 13.5%, of zinc (II), mercury (II), and lead (II), respectively, of growth relative to control without metal, and, therefore, probably is resistant to the metals, although, it grew a 16% with 1.4 g/L of arsenic (III), and it is very sensitive to cobalt (II) (12.8% with 600 mg/L) ( Figure 1 ).…”

“…The fungal strain of A. niger was isolated from the polluted air in a fuel station, near to the Faculty of Chemical Science, belonging to the Autonomous University of San Luis Potosí (San Luis Potosi, Mexico) [ 17 ], and this was used for the screening. In addition to the above, this fungus was conditioned for years under conditions of biological stress and was inoculated in culture media containing between 0 and 500 ppm of different heavy metals such as chromium, lead, cadmium, arsenic, etc.…”

“…There are many reports of the isolation of resistant microorganisms to heavy metals and the use of microbial biomass for the removal of heavy metals, from industrial wastewater and/or contaminated water: the resistance and removal of Rhizopus stolonifer to lead, cadmium, copper, and zinc [ 11 ], the tolerance and removal mechanisms of heavy metals (lead, cadmium, and chromium), by the fungus Pleurotus ostreatus HAAS [ 12 ], Bacillus megaterium nickel resistance and her capacity of removal [ 13 ], heavy metal susceptibility and removal potential (mercury, copper, and lead) of Rhodotorula mucilaginosa [ 14 ], the resistance of Alcaligenes sp. BAPb.1 to lead (II), copper (II), zinc (II), nickel (II), and chromium (VI), and his capacity for removal of lead (II) [ 15 ], the isolation and identification of fungi and yeast resistant to lead (II) [ 16 ], the resistance and removal of chromium (VI) by Aspergillus niger [ 17 ], the removal of different heavy metals by A. niger [ 18 ], the removal of lead, cadmium, copper, and nickel by A. niger [ 19 ], the removal of aluminum, iron, lead, and zinc by A. niger during the bioleaching process [ 12 ], and the removal of copper (II), manganese (II), zinc (II), nickel (II), iron (III), lead (II), and cadmium (II) by immobilized cells of A. niger [ 20 ], with highly satisfactory results. This work reports the removal of different heavy metal in an aqueous solution by a strain of A. niger which is highly resistant to some heavy metals.…”