Differentiation of Lactobacilli Strains by Electrophoretic Protein Profiles

SAVOY DE GIORI, G.; HEBERT, E.M.; RAYA, R.R.

Food Microbiology Protocols. Series Methods in Biotechnology

Humana Press Inc.

Lugar: Totowa, New Jersey. pp 191-196; Año: 2001; p. 191 - 196

Lactic acid bacteria (LAB) comprise a diverse group of Gram-positive, nonsporeforming microorganisms (1). Fermentable carbohydrates are used as energy sources and are degraded to lactate (homofermentatives) or to lactate and additional products such as acetate, ethanol, carbon dioxide, formate or succinate (heterofermentatives). Lactobacilli species are widely used in food technology. Manufacture of high quality products requieres close attention to characterization, differenciation and maintenance of lactobacilli starter culture strains. The species identification of LAB depends mainly on physiological and biochemical criteria. These conventional methods are time-comsuming, difficult and the results are often ambiguous. Therefore, for microbiological quality control, are necessary to develop more reliable and rapid identification methods. The electrophoretic separation of cellular proteins is a sensitive technique, applied in bacterial systematics, that mainly provides information on the similarity of strains within the same species or subspecies. The present chapter deals with the most common technique of polyacrylamide gel electrophoresis (PAGE) in the presence of denaturing agents (SDS) of whole and wall cell-associated proteins extracts for strain typing of lactobacilli. These methods will be useful for culture maintenance by giving each particular strain a fingerprint.