Bioaugmentation of chromium-polluted soil microcosms withCandida tropicalisdiminishes phytoavailable chromium

Abstract

Aim: Localization of Cr(VI) removal activity in Candida tropicalis strain and the study of its Cr(VI) removal capacity in soil. Methods and Results: Candida tropicalis strain HE650140 showed a remarkable capacity to completely reduce 50 mg l À1 of Cr(VI) in 48 h under aerobic conditions; however, a small change in total content of chromium in the culture liquid was detected, which can be explained by the formation of Cr (III). Fractionation of the cells showed that chromium removal activity was present in both the cytoplasm and membrane. The bioaugmentation of Cr (VI)-contaminated soil microcosms by live and dead biomass showed that yeast inoculation diminishes phytoavailable chromium from soils, improving different growth parameters of clover. Conclusion:The Cr(VI) removal activity was found in both cytoplasmic and membrane fractions. Both live and dead biomass of C. tropicalis were capable to reduce Cr(VI) in the soil and limit the toxicity of this metal to clover seedlings. Significance and Impact of the Study: This study is one of the few documents that present the ability of dead yeast to limit phytoavailability of Cr(VI) from soil. This is of great significance in bioremediation of Cr(VI)-contaminated soil.

Biosorption of Heavy Metals by Candida albicans

“…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].…”

“…These observations are consistent for the removal of Cr(VI) by Candida utilis [44], for contaminated soil for bioremediation of Cr(VI) [45], for the strains P. jadinii M9 and P. anomala M10 for Cr(VI) reduction (26-104 μg/mL) [33], and for Candida sp. isolated from a sewage treatment plant for removal of Cr(VI) [46] and are different from the removal of Cr(VI) by C. tropicalis [29].…”

“…It was found that a higher removal, which is proportional to the biosorption, occurs at 2 days and at a pH of 1.0. It was reported a time of 24 h Cyberlindnera fabianii, Wickerhamomyces anomalus, and Candida tropicalis, at a pH range between 2 and 4 for the three species [27]; the removal of Cr(VI) (100%) by Cyberlindnera fabianii at 48 h [28]; Candida tropicalis isolated from chromium-contaminated site removal 50 mg/L of the metal at 48 h [29]; and Candida intermedia in the biosorption of Cr(III) and Cr(VI) were reported [30]. Permeability and porosity of the cell wall can affect the incubation time of each Advances in Bioremediation and Phytoremediation microorganism, giving greater or lesser exposure of the functional groups in the cell wall of the biomass analyzed [31].…”

Yeast Biomass: An Alternative for Bioremediation of Heavy Metals

“…Bioaugmentation was carried out using different microorganisms. The yeast-based bioaugmentation was specifically shown to be an advantageous soil and water clean-up approach for contaminated sites, containing heavy metals and/or organic pollutants [118][119][120].…”

Removal of chromium (VI) in aqueous solution by oat biomass (Avena sativa)

“…Changes in the permeability of unknown origin, could partly explain the differences founded in the incubation time, providing greater or lesser exposure of the functional groups of the cell wall of the biomass analyzed (Ahemad, 2014;Tejada Tovar et al, 2015). On the other hand, it has been reported the ability of the yeast Candida tropicalis to remove Cr was tested in artificially contaminated soils in a microcosm system to simulate natural environmental conditions, showing reduction of 72.2 % of 40 mg/L Cr(VI) (Bahafid et al 2013). An A. niger strain isolated from a tannery was used in an airlift reactor for the treatment of tanning wastewater, leading to maximum removal efficiency by adsorption of 88 % of an initial Cr (III) concentration of 1300 mg/L .…”