Influence of Zinc(II) and Copper(II) Ions on Streptomyces Bacteria Revealed by Electrochemistry

• Published in: International journal of electrochemical science 2011-06, Vol.6 (6), p.2171-2191
• Main Authors: Majzlik, Petr, Strasky, Andrej, Adam, Vojtech, Nemec, Miroslav, Trnkova, Libuse, Zehnalek, Josef, Hubalek, Jaromir, Provaznik, Ivo, Kizek, Rene
• Format: Article
• Language: English
• Subjects: automated electrochemical detection; bacteria; bioremediation; differential pulse voltammetry; heavy metal
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)18175-2

Heavy metals are toxic and can be harmful for organisms. For this reason, a number of organisms including bacteria develop processes which are able to withstand the effects of these pollutants. An accumulation of heavy metals in different bacterial strains in soil has been observed and could be used in the process of remediation of soils contaminated by heavy-metal-pollutants. In this study, Streptomyces, well known for their capacity to accumulate heavy metals from the environment, were selected. The ability to accumulate heavy metals in biomass was determined for three strains both collection strain (CCM3243) and two strains isolated from soil exposed to heavy traffic emissions in the centre of Brno (ON3 and M4). The aim was to observe the effect of zinc(II) and copper(II) ions on growth characteristics and content the metal ions in selected bacterial strains using an automated electrochemical detection. Primarily, the common characteristic as growth and minimum inhibitory concentration (MIC, the lowest concentration of metal that completely stops the growth of target microorganisms) was determined. Based on the results of the MICs on solid medium (agar) can be studied organisms of the genus P. flavovirens out in order with respect to their sensitivity to zinc(II) and copper(II) ions as follows: ON3 » CCM3243 > M4. The results also show that the collection strain is more sensitive to copper(II) and zinc(II) ions in comparison with ON3 and M4 strains. Further, we aimed at determination of zinc(II) and copper(II) ions in three selected strains, which were cultivated in the presence of different concentrations of zinc(II) (0, 50 and 100 µM) and copper(II) ions (0, 100, 200 and 500 µM). Limit of detection estimated as 3 S/N was 1 nM for zinc(II) ions and limit of quantification as 10 S/N was 5 nM. The accumulation data obtained correlate very well with the results of biological experiments, especially ON3 strain with the highest resistance also has the ability to accumulate highest concentration of metal ions in the cell wall.