Bioaccumulation of zinc ions in Lactobacillus rhamnosus B 442 cells under treatment of the culture with pulsed electric field

Abstract

Pulsed electric field (PEF) technology was used to enrich Lactobacillus rhamnosus B 442 cells in zinc ions to obtain source of this element with high bioavailability. The highest bioaccumulation of zinc was achieved when electroporation was performed at optimal parameters: field strength of 3.0 kV/cm, pulse width of 20 µs, electroporation time of 15 min after 20 h of culturing and at zinc concentration of 500 µg/mL medium. The maximum bioaccumulation of ions in cells (2.85 mg Zn/g d.m.) was 164% higher than in the control sample which was supplemented with zinc but not treated with PEF. The action of PEF did not reduce the total number of microorganisms in the medium or the biomass of bacteria.