Search results for " impasti acidi"

In situ activity of a bacteriocin-producing Lactococcus lactis strain. Influence on the interactions between lactic acid bacteria during sourdough fe…

2005

Aims:  To biochemically characterize the bacteriocin produced by Lactococcus lactis ssp. lactis M30 and demonstrate its effect on lactic acid bacteria (LAB) during sourdough propagation. Methods and Results:  A two-peptide bacteriocin produced by L. lactis ssp. lactis M30 was purified by ion exchange, hydrophobic interaction and reversed phase chromatography. Mass spectrometry of the two peptides and sequence analysis of the ltnA2 gene showed that the bacteriocin was almost identical to lacticin 3147. During a 20-day period of sourdough propagation the stability of L. lactis M30 was demonstrated, with concomitant inhibition of the indicator strain Lactobacillus plantarum 20, as well as the …

A taxonomic survey of lactic acid bacteria isolated from wheat (Triticum durum) kernels and non-conventional flours

2007

In order to explore the correspondence between raw material- and mature sourdough-lactic acid bacterial (LAB) communities, 59 Italian wheat (Triticum durum) grain samples, one bran and six non-conventional flour samples were analyzed through a culture-dependent approach. The highest cell count by an agar medium specific for LAB was 2.16 log CFU/g. From about 2300 presumptive LAB (Gram-positive and catalase-negative) colonies collected, a total of 356 isolates were subjected to identification by a genetic polyphasic strategy consisting of RAPD-PCR analysis, partial 16S rRNA gene sequencing, species-specific and multiplex PCRs. The isolates were recognized as 137 strains belonging to Aerococc…

Rapid differentiation and in situ detection of 16 sourdough lactobacillus species by multiplex PCR.

2005

ABSTRACT A two-step multiplex PCR-based method was designed for the rapid detection of 16 species of lactobacilli known to be commonly present in sourdough. The first step of multiplex PCR was developed with a mixture of group-specific primers, while the second step included three multiplex PCR assays with a mixture of species-specific primers. Primers were derived from sequences that specify the 16S rRNA, the 16S-23S rRNA intergenic spacer region, and part of the 23S rRNA gene. The primer pairs designed were shown to exclusively amplify the targeted rrn operon fragment of the corresponding species. Due to the reliability of simultaneously identifying Lactobacillus plantarum , Lactobacillus…

Lactobacillus rossii sp. nov. isolated from wheat sourdough

2005

Screening of sourdough lactic acid bacteria for bacteriocin production resulted in the isolation of a Gram-positive, catalase-negative, non-spore-forming, non-motile rod bacterium (strain CS1T) that could not be associated with any previously described species. Comparative 16S rRNA gene sequence analysis recognized strain CS1T as a distinct member of the genus Lactobacillus. By a species-specific PCR strategy, five additional strains previously isolated from sourdoughs were found to belong to the same species as strain CS1T, as confirmed by 16S rRNA gene sequence analysis. The closest related species were Lactobacillus durianis, Lactobacillus malefermentans and Lactobacillus suebicus, with …

Combination of multiplex PCR and PCR-DGGE for monitoring common sourdough-associated Lactobacillus species

2006

A combination of denaturing gradient gel electrophoresis (DGGE) and a previously described multiplex PCR approach was employed to detect sourdough lactobacilli. Primers specific for certain groups of Lactobacillus spp. were used to amplify fragments, which were analyzed by DGGE. DGGE profiles obtained from Lactobacillus type strains acted as standards to analyze lactobacilli from four regional Abruzzo (central Italy) sourdoughs.

Application of novel polyphasic approach to study the lactobacilli composition of sourdoughs from the Abruzzo region (Central Italy)

2006

Il microbiota lattico degli impasti acidi e delle materie prime usate in panificazione.

2008

Exploitation of lactic acid bacteria potentiality for improving sourdough breads

2005

Characterization of bacteriocin-like inhibitory substances (BLIS) from sourdough lactic acid bacteria and evaluation of their in vitro and in situ ac…

2004

Purification and characterization of an intracellular family 3 β-glucosidase from Lactobacillus sanfranciscensis CB1

2005

Lactobacillus sanfranciscensis CB1 uses cellobiose and other β-glucosides (methyl-β-glucoside, arbutin, amygdalin and salicin) as carbon sources. A hexameric ca. 288 kDa β-glucosidase was purified to homogeneity from Lact. sanfranciscensis CB1 by four chromatographic steps. The enzyme was optimally active at pH 7.5 and 40°C. It had a pI of ca. 4.38 and a D55°C value of ca. 27 sec. Almost total inhibition was found with sulfhydryl-modifying agents and divalent cations such as Cu2+, Co2+, Hg2+, Ni2+ and Fe2+ at a concentration of 2 mM. The enzyme was active towards β-(1→4) substrates such as p-nitrophenyl-β-D-glucoside, -D-galactoside and -L-rhamnoside, and cellobiose. The sequencing of four …