Zinc Binding by Lactic Acid Bacteria
Jasna Mrvčić1*, Tatjana Prebeg2, Lidija Barišić1, Damir Stanzer1, Višnja Bačun-Družina1 and Vesna Stehlik-Tomas1
1Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia
2Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia
Article history:
Received December 16, 2008
Accepted July 17, 2009
Key words:
zinc, Lactobacillus, adsorption, trace elements, LAB
Summary:
Zinc is an essential trace element in all organisms. A common method for the prevention of zinc deficiency is pharmacological supplementation, especially in a highly available form of a metalloprotein complex. The potential of different microbes to bind essential and toxic heavy metals has recently been recognized. In this work, biosorption of zinc by lactic acid bacteria (LAB) has been investigated. Specific LAB were assessed for their ability to bind zinc from a water solution. Significant amount of zinc ions was bound, and this binding was found to be LAB species-specific. Differences among the species in binding performance at a concentration range between 10–90 mg/L were evaluated with Langmuir model for biosorption. Binding of zinc was a fast process, strongly influenced by ionic strength, pH, biomass concentration, and temperature. The most effective metal-binding LAB species was Leuconostoc mesenteroides (27.10 mg of Zn2+ per gram of dry mass bound at pH=5 and 32 °C, during 24 h). FT-IR spectroscopy analysis and electron microscopy demonstrated that passive adsorption and active uptake of the zinc ions were involved.
*Corresponding author: 
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