Whey valorization concerns have led to recent interest on the production of whey beverage simulating
kefir. In this study, the structure and microbiota of Brazilian kefir grains and beverages obtained from
milk and whole/deproteinised whey was characterized using microscopy and molecular techniques.
The aim was to evaluate its stability and possible shift of probiotic bacteria to the beverages. Fluorescence
staining in combination with Confocal Laser Scanning Microscopy showed distribution of yeasts in
macro-clusters among the grain’s matrix essentially composed of polysaccharides (kefiran) and bacteria.
Denaturing gradient gel electrophoresis displayed communities included yeast affiliated to Kluyveromyces
marxianus, Saccharomyces cerevisiae, Kazachatania unispora, bacteria affiliated to Lactobacillus kefiranofaciens
subsp. Kefirgranum, Lactobacillus kefiranofaciens subsp. Kefiranofaciens and an uncultured
bacterium also related to the genus Lactobacillus. A steady structure and dominant microbiota, including
probiotic bacteria, was detected in the analyzed kefir beverages and grains. This robustness is determinant
for future implementation of whey-based kefir beverages.Coordenação de Aperfeiçoamento de
Pessoal de Nível Superior (CAPES), CAPES-GRICES