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(-1) 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.
Keywords: Candida tropicalis; Cr(VI) removal; bioaugmentation; bioremediation; cell fractionation; soil.
© 2013 The Society for Applied Microbiology.