RESUMO
Selenium is an essential micronutrient for living beings, as it helps to maintain the normal physiological functions of the organism. The numerous discoveries involving the importance of this element to the health of human beings have fostered interest in research to develop enriched and functional foods. The present study evaluated the potential for bacterial strains of Enterococcus faecalis (CH121 and CH124), Lactobacillus parabuchneri (ML4), Lactobacillus paracasei (ML13, ML33, CH135, and CH139), and Lactobacillus plantarum (CH131) to bioaccumulate Se in their biomass by adding different concentrations of sodium selenite (30 to 200 mg/L) to the culture medium. Quantification of Se with UV and visible molecular absorption spectroscopy showed that the investigated bacteria were able to bioaccumulate this micromineral into their biomass. Two of the L. paracasei strains (ML13 and CH135) bioaccumulated the highest Se concentrations (38.1 ± 1.7 mg/g and 40.7 ± 1.1 mg/g, respectively) after culture in the presence of 150 mg/L of Se. This bioaccumulation potential has applications in the development of dairy products and may be an alternative Se source in the diets of humans and other animals.
Assuntos
Enterococcus faecalis/metabolismo , Lactobacillus/metabolismo , Selênio/metabolismo , Animais , Bovinos , Meios de Cultura/análise , Meios de Cultura/metabolismo , Laticínios/microbiologia , Enterococcus faecalis/genética , Enterococcus faecalis/crescimento & desenvolvimento , Humanos , Ácido Láctico/metabolismo , Lactobacillus/crescimento & desenvolvimento , Selenito de Sódio/análise , Selenito de Sódio/metabolismoRESUMO
The present paper describes the validation of a spectrophotometry method involving molecular absorption in the visible ultraviolet-visible (UV-Vis) region for selenium (Se) determination in the bacterial biomass produced by lactic acid bacteria (LAB). The method was found to be suitable for the target application and presented a linearity range from 0.025 to 0.250â¯mg/L Se. The angular and linear coefficients of the linear equation were 1.0678 and 0.0197â¯mg/L Se, respectively, and the linear correlation coefficient (R2) was 0.9991. Analyte recovery exceeded 96% with a relative standard deviation (RSD) below 3%. The Se contents in LAB ranged from 0.01 to 20â¯mg/g. The Se contents in the bacterial biomass determined by UV-Vis were not significantly different (pâ¯>â¯0.05) those determined by graphite furnace atomic absorption spectrometry. Thus, Se can be quantified in LAB biomass using this relatively simpler technique.
