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Isolation and characterization of nickel-accumulating yeasts
H Kambe-Honjoh1, A Sugawara, K Yoda
1Department of Biotechnology, University of Tokyo, Japan.
Applied Microbiology and Biotechnology
|November 14, 1997
Summary
Three Candida yeast strains efficiently remove heavy metal ions like nickel, copper, and zinc from water. These robust strains maintain their metal removal capabilities even after harsh treatments, offering potential for bioremediation.
Area of Science:
- Environmental Microbiology
- Bioremediation
- Metal Ion Toxicology
Background:
- Heavy metal contamination in aqueous solutions poses significant environmental and health risks.
- Developing efficient and sustainable methods for heavy metal removal is crucial for environmental protection.
- Microbial bioremediation offers a promising, eco-friendly approach to treat contaminated water.
Purpose of the Study:
- To identify and characterize yeast strains capable of efficiently removing heavy metal ions from aqueous solutions.
- To investigate the heavy metal removal efficiency of selected yeast strains, specifically for nickel (Ni).
- To assess the tolerance and reusability of these yeast strains under various conditions.
Main Methods:
- Screening of wild yeast strains for growth in the presence of nickel chloride (NiCl2).
- Selection of high-performing yeast strains based on their nickel removal efficiency from aqueous solutions.
- Identification of selected yeast strains using Candida species identification.
- Testing heavy metal removal efficiency across different pH levels and initial metal concentrations.
- Evaluating yeast strain reusability and tolerance to EDTA, HCl, and heat treatments.
Main Results:
- Three wild yeast strains, identified as Candida species, demonstrated efficient removal of Ni, copper (Cu), and zinc (Zn).
- Optimal nickel uptake occurred at pH 4.0–7.0, with reduced efficiency below pH 3.0.
- Nickel ion uptake was proportional to the initial NiCl2 concentration up to approximately 4 mM.
- The yeast strains retained their nickel removal ability after repeated use, treatment with EDTA or HCl, and heat exposure.
Conclusions:
- Selected Candida yeast strains are effective biosorbents for removing multiple heavy metal ions from water.
- These yeast strains exhibit robustness and stability, allowing for repeated use in bioremediation applications.
- The findings support the potential of these yeast strains for practical application in treating heavy metal-contaminated wastewater.