Chromium (VI) tolerance and bioaccumulation by Candida tropicalis isolated from textile wastewater

Abstract

AbstractIn the present study a yeast strain isolated from industrial wastewater, identified as Candida tropicalis, showed chromium (Cr) tolerance level up to 5 mM. Yeast grown in minimal salt medium containing Cr (VI) ions for 48 h and crude enzyme extracts were tested for chromate reductase activity. Optimum temperature and pH of chromate reductase were 30 °C and pH of 7. The enzyme activity was greatly enhanced in the presence of divalent metal cations. Total protein profile revealed some protein bands were present in hexavalent chromium [Cr (VI)] treated samples but were absent in non-treated samples, especially low molecular-weight protein bands in the mass range of < 25 kDa with greater intensity in Cr (VI) treated samples. Yeast cells were able to uptake Cr (VI) between 21 and 80 mg g− 1 within 2–12-d of time, indicating yeast strain promising potential for Cr (VI) removal from the wastewater. The present study results suggest that C. tropicalis is a suitable candidate for bioremediating chromium ions from the contaminated-environment.