评估酵母菌株作为水生环境中金属离子微量富集的可能媒介。

Evaluation of yeast strains as possible agents for trace enrichment of metal ions in aquatic environments.

作者信息

Mapolelo M, Torto N, Prior B

机构信息

Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana.

出版信息

Talanta. 2005 Feb 28;65(4):930-7. doi: 10.1016/j.talanta.2004.08.020.

DOI:10.1016/j.talanta.2004.08.020

PMID:18969891

Abstract

Sorption properties of six yeast strains were evaluated for trace enrichment of metal ions; Cd(2+), Cr(3+), Cr(6+), Cu(2+), Pb(2+), and Zn(2+) from aqueous environments. Metal concentration was determined by flame atomic absorption spectrometry (FAAS). The results showed that trace enrichment of the metals under study with yeast, was dependent on the pH and available metal ions. Enrichment time of 30min gave an optimum metal uptake. The presence of Na(+), K(+), and Ca(2+) suppressed the uptake of Pb by less than 5%, but suppressed the uptake of Zn by between 15 and 25%. Mg(2+), Cu(+), Cu(2+), Cr(3+) Cr(6+), Cd(2+), and Zn(2+) suppressed the uptake of Pb by between 25 and 35%, and that of Zn by between 15 and 25%. For both Pb and Zn, Cd had the highest suppression of 35 and 30%, respectively for baker's yeast (Saccharomyces cerevisiae). Baker's yeast achieved enrichment factors (EF) of 23, 4, 100, and 1 for dam water, stream water, treated wastewater, and industrial effluent samples for Cu, Pb, Zn, and Cr, respectively. The recoveries of optimised Cd and Cr samples spiked with 2mugml(-1) of the metal could reach up to 90%, but never exceeded 66% for 10mugml(-1) samples. For Cu and Pb, the recoveries generally increased independent of concentration, however they were not as high as those for Zn, which exceeded 90% for all the samples spiked with 10mugml(-1) of the metal. S. cerevisiae PR 61/3 had the highest EF for Cr as compared to the other yeast strains. S. cerevisiae PRI 60/78 was the only yeast strain which was able to enrich Cd in all the samples. Baker's yeast had the highest EFs for Cu and Zn as compared to the other yeast strains without pH adjustment of the water samples. Candida tropicalis attained the highest EFs for Pb as compared to the other yeast strains. The results indicate that all the yeast strains used had a high affinity for Zn based on the EF values achieved. The results from these studies demonstrate that yeast is a viable trace metal enrichment agent that can be used freely suspended in solution to enrich metal ions at relatively low concentrations. This has ramifications on the traditional methods of sampling, sample collection, and transportation from remote sampling sites.

摘要

评估了六种酵母菌株对水环境中金属离子（Cd(2+)、Cr(3+)、Cr(6+)、Cu(2+)、Pb(2+)和Zn(2+)）的痕量富集吸附特性。通过火焰原子吸收光谱法（FAAS）测定金属浓度。结果表明，酵母对所研究金属的痕量富集取决于pH值和可利用的金属离子。30分钟的富集时间可实现最佳的金属吸收。Na(+)、K(+)和Ca(2+)的存在使Pb的吸收抑制率低于5%，但使Zn的吸收抑制率在15%至25%之间。Mg(2+)、Cu(+)、Cu(2+)、Cr(3+)、Cr(6+)、Cd(2+)和Zn(2+)使Pb的吸收抑制率在25%至35%之间，使Zn的吸收抑制率在15%至25%之间。对于Pb和Zn，面包酵母（酿酒酵母）中Cd的抑制率最高，分别为35%和30%。面包酵母对铜、铅、锌和铬的富集因子（EF）分别为：对于大坝水、溪水、处理后的废水和工业废水样品，Cu为23、Pb为4、Zn为100、Cr为1。添加2μg/ml金属的优化Cd和Cr样品的回收率可达90%，但对于添加10μg/ml金属的样品，回收率从未超过66%。对于Cu和Pb，回收率通常随浓度增加而提高，但不如Zn高，添加10μg/ml金属的所有样品中Zn的回收率均超过90%。与其他酵母菌株相比，酿酒酵母PR 61/3对Cr的EF最高。酿酒酵母PRI 60/78是唯一能够在所有样品中富集Cd的酵母菌株。在不调节水样pH值的情况下，与其他酵母菌株相比，面包酵母对Cu和Zn的EF最高。与其他酵母菌株相比，热带假丝酵母对Pb的EF最高。结果表明，基于所获得的EF值，所有使用的酵母菌株对Zn具有高亲和力。这些研究结果表明，酵母是一种可行的痕量金属富集剂，可自由悬浮在溶液中用于富集相对低浓度的金属离子。这对传统的采样、样品采集和从偏远采样地点运输样品的方法产生了影响。