Issue 18, 2012

Highly selective preconcentration of ultra-trace cadmium by yeast surface engineering

Abstract

The potential of selective cell-sorption for separation/preconcentration of ultra-trace heavy metals was exploited by surface engineering of Saccharomyces cerevisiae cells. The general idea is to display the cadmium-binding peptide on the cell surface in order to enhance the covalent interaction between cadmium and the yeast cells. By immobilizing the surface-engineered yeast cells onto cytopore® microcarrier beads for cadmium adsorption, we demonstrated that with respect to the native yeast 600-fold and 25–1000-fold improvements were observed respectively for the tolerance of ionic strength and the tolerant capability toward various metal cations after surface engineering. Based on these observations, a novel procedure for selective cadmium preconcentration was developed with detection by graphite furnace atomic absorption spectrometry (GFAAS), employing the engineered S. cerevisiae cell-loaded cytopore® beads as a renewable sorption medium incorporated into a sequential injection lab-on-valve system. The cadmium retained on the yeast cell surface was eluted with a small amount of nitric acid and quantified with GFAAS. Within a range of 5–100 ng L−1 and a sample volume of 1 mL, an enrichment factor of 30 was achieved along with a detection limit of 1.1 ng L−1, a sampling frequency of 20 h−1 and a precision of 3.3% RSD at 50 ng L−1. The procedure was validated by analyzing cadmium in certified reference materials and a series of environmental water samples.

Graphical abstract: Highly selective preconcentration of ultra-trace cadmium by yeast surface engineering

Article information

Article type
Paper
Submitted
06 Jun 2012
Accepted
04 Jul 2012
First published
05 Jul 2012

Analyst, 2012,137, 4193-4199

Highly selective preconcentration of ultra-trace cadmium by yeast surface engineering

T. Yang, X. Zhang, M. Chen and J. Wang, Analyst, 2012, 137, 4193 DOI: 10.1039/C2AN35755K

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