| Abstract [eng] |
Due to environmental contamination, certain plants can concentrate essential and non-essential heavy metals such as cadmium in their roots and/or shoots to levels that can cause cereal safety problems. The present study was dedicated to study the potential of antimicrobial lactic acid bacteria (L. sakei KTU05-6 KTU05-6, Pediococcus acidilactici KTU05-7, Pediococcus pentosaceus, respectively, KTU05-8, KTU05-9 and KTU05-10) treatment for decontamination of Cd using artificially Cd contaminated wheat grains (model samples). The decontamination potential of LAB culture against Cd on sprouting wheat grain seedlings were examined by laboratory trials using Atomic Absorption Spectroscopy. Cd pollution and LAB treatment influence on seed germination and seedling growth was also investigated. Results showed, that cadmium bioaccumulation during wheat grains germination was obtained higher in roots in average in compare with seeds (both germinated and non-germinated seeds). Bio-treatment effects on cadmium reduction were depending on type of LAB strains and their supernatants. pH played significant role on the reduction of cadmium in grains. The highest reduction level of cadmium had been obtained by using supernatants of P. acidilactici KTU05-7 at pH 7. Reduction of cadmium depending from strains followed by Pa7>Pp9> Ls. Thus, with selected LAB strains and grain treatment conditions in mind, the possibilities of the use of LAB bio-products for the decontamination of metal polluted soils could be applied. Additionally, research has been focused on the main metabolite of LAB – lactic acid and its conversion possibilities using catalysts to make pyruvic acid. Last part of the experiment has been carried out during Erasmus+ visit in Cordoba University (Spain), Department of Organic Chemistry. Fe2O3 catalyst were synthesized using biomass and used directly for catalytic conversion of lactic acid to pyruvic acid by oxidation. Further the catalyst has been extremely analysed which provides remarkable yield (90%) of lactic acid into pyruvic acid. The highest conversion rate of lactic acid to pyruvic acid was obtained based on retention time, type of catalyst and solvent. Using optimal conditions (acetonitrile, Fe2O3,) lactic acid has been catalytically fully converted to pyruvic acid by oxidation. Flow reactor was selected for the better conversion of lactic acid to pyruvic acid in compare with microwave digestion and conventional heating because it allows more exactly to optimise the temperature and pressure during catalysis based on solvent, catalyst and the reaction mixture. |
