Molecular and phenotypic characterization of Lactobacillus curvatus isolated from handmade Brazilian salami

Abstract

17 Lactobacillus curvatus and one Lactobacillus brevis isolate were obtained from salami. The isolates were previously selected according to the desirable characteristics regarding technological criteria. Identification was based primarily on the biochemical carbohydrate assimilation profile, and later by amplified 16S rDNA restriction analysis (ARDRA). Due to inconsistencies in the results found by the identification methods employed, the 16S rRNA gene was partially sequenced and the result confirmed identity of L. curvatus, as predicted by ARDRA, which shows that this molecular technique is efficient in identifying the species. All isolates of L. curvatus were characterized by the molecular technique of random amplified polymorphic DNA (RAPD). In order to analyze the relationships existing between the isolates, taxonomic dendrograms were obtained based on molecular profile, what was suitable for the typing. The molecular techniques are efficient in the identification of Lactobacillus sp. isolates, which can be complementary or even substitute biochemical techniques. Thus, these molecular methods offer a fast and economic way for the identification and characterization of lactic acid bacterial with a potential use as starter cultures in the elaboration of handmade fermented products.

Key words: 16S amplified ribosomal DNA restriction analysis (ARDRA), random amplified polymorphic DNA (RAPD), lactobacilli, microbial genetics.