Bioaccumulation and distribution of selenium in Enterococcus durans.
Selenium is an essential nutrient for all living organisms. Under appropriate conditions lactic acid bacteria (LAB) are capable for accumulating large amounts of trace elements, such as selenium, and incorporating them into organic compounds. In this study, the capacity of selenium bioaccumulation by Enterococcus durans LAB18s was evaluated. The distribution of organic selenium in selenium-enriched E. durans LAB18s biomass was analyzed, and the highest percentage of organic selenium was found in the fraction of total protein, followed by the fractions of polysaccharides and nucleic acids. When the protein fraction was obtained by different extractions (water, NaCl, ethanol and NaOH) it was demonstrated that alkali-soluble protein showed the higher Selenium content. Analysis of protein fractions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that selenium was present in the proteins ranging from 23 to 100kDa. The cells were analyzed by scanning electron microscopy (SEM); scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) and transmission electron microscopy (TEM). SEM, TEM and SEM/EDS showed the morphology, the selenium particles bioaccumulated into and on the cells and the amounts of selenium present into the cells, respectively. Thus, the isolate E. durans LAB18s can be a promising probiotic to be used as selenium-enriched biomass in feed trials.
Laboratório de Bioquímica e Microbiologia Aplicada, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brazil.
Simone
S
Pieniz
Centro de Engenharias, Universidade Federal de Pelotas, 96010-280 Pelotas, Brazil.
Robson
R
Andreazza
Laboratório de Bioquímica e Microbiologia Aplicada, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brazil.
Michele Bertoni
MB
Mann
Departamento de Ciência do Solo, Universidade Federal do Rio Grande do Sul, 91540-000 Porto Alegre, Brazil.
Flávio
F
Camargo
Laboratório de Bioquímica e Microbiologia Aplicada, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brazil. Electronic address: abrand@ufrgs.br.
Adriano
A
Brandelli
D018533:Biomass; D016983:Enterococcus / Q000737:chemistry* / Q000378:metabolism*; D012643:Selenium / Q000032:analysis* / Q000378:metabolism*
D012643:Selenium
Bioinorganic molecules; Enterococci; Selenium; Selenoprotein