Bioremediation potential of Cd by transgenic yeast expressing a metallothionein gene from Populus trichocarpa

De Oliveira, V. H., Ullah, I. ORCID: https://orcid.org/0000-0002-9367-6741, Dunwell, J. M. ORCID: https://orcid.org/0000-0003-2147-665X and Tibbett, M. ORCID: https://orcid.org/0000-0003-0143-2190 (2020) Bioremediation potential of Cd by transgenic yeast expressing a metallothionein gene from Populus trichocarpa. Ecotoxicology and Environmental Safety, 202. 110917. ISSN 0147-6513 doi: 10.1016/j.ecoenv.2020.110917

Abstract/Summary

Cadmium (Cd) is an extremely toxic environmental pollutant with high mobility in soils, which can contaminate groundwater, increasing its risk of entering the food chain. Yeast biosorption can be a low-cost and effective method for removing Cd from contaminated aqueous solutions. We transformed wild-type Saccharomyces cerevisiae (WT) with two versions of a Populus trichocarpa gene (PtMT2b) coding for a metallothionein: one with the original sequence (PtMT2b ‘C’) and the other with a mutated sequence, with an amino acid substitution (C3Y, named here: PtMT2b ‘Y’). WT and both transformed yeasts were grown under Cd stress, in agar (0; 10; 20; 50 µM Cd) and liquid medium (0; 10; 20 µM Cd). Yeast growth was assessed visually and by spectrometry OD600. Cd removal from contaminated media and intracellular accumulation were also quantified. PtMT2b ‘Y’ was also inserted into mutant strains: fet3fet4, zrt1zrt2 and smf1, and grown under Fe-, Zn- and Mn-deficient media, respectively. Yeast strains had similar growth under 0 µM, but differed under 20 µM Cd, the order of tolerance was: WT < PtMT2b ‘C’ < PtMT2b ‘Y’, the latter presenting 37% higher growth than the strain with PtMT2b ‘C’. It also extracted ~80% of the Cd in solution, and had higher intracellular Cd than WT. Mutant yeasts carrying PtMT2b ‘Y’ had slightly higher growth in Mn- and Fe-deficient media than their non-transgenic counterparts, suggesting the transgenic protein may chelate these metals. S. cerevisiae carrying the altered poplar gene offers potential for bioremediation of Cd from wastewaters or other contaminated liquids.

Item Type	Article
URI	https://reading-pure-test.eprints-hosting.org/id/eprint/91328
Identification Number/DOI	10.1016/j.ecoenv.2020.110917
Refereed	Yes
Divisions	Life Sciences > School of Agriculture, Policy and Development > Department of Crop Science Central Services Life Sciences > School of Agriculture, Policy and Development > Department of Sustainable Land Management
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