42 research outputs found
The role of environmental factors and medium composition on bacteriocin-like inhibitory substances (BLIS) production by Enterococcus mundtii strains.
No full textEffect of environmental and nutritional factors on the production of bacteriocin-like inhibitory substances (BLIS) by Enterococcus faecium strains
No full textFive bacteriocin-like inhibitory substances (BLIS)-producer Enterococcus faecium strains (WGW7.2, WGJ17.2,
WGJ21.2, WGJ28.1 and WGW33.2) were characterized for their antimicrobial compound production under several growth conditions, at different concentrations and with different sources of nutritional factors and in the presence of ethanol and NaCl.
The strains showed different behaviours. MRS and SDB were found to be the optimal media for BLIS expression.
A higher BLIS production was observed at 30° and 37°C and at a pH in the neutral range. Low or no BLIS activity was detected after growth in the absence of nitrogen sources, carbohydrates, MgSO4 and MnSO4. Ethanol did not generally play a negative role, while NaCl determined a consistent decrease in BLIS activity that was proportional to its concentration. Due to the absence
of plasmids, BLIS production by all strains was chromosomally encoded. This study is part of a more comprehensive study aimed at characterizing lactic acid bacteria (LAB) associated with the raw materials used to prepare sourdough
“Application of a novel polyphasic approach to study the lactobacilli composition of sourdoughs from the Abruzzo region (central Italy)”
No full textAims: To characterize the lactobacilli community of 20 sourdoughs using a
novel polyphasic approach.
Methods and Results: A polyphasic approach, consisting of a two-step multiplex
polymerase chain reaction (PCR) system, 16S rRNA gene sequence analysis
and physiological features, was applied to identify 127 isolates, representing
about 37% of the presumptive lactobacilli collected from sourdough samples.
Multiplex PCR successfully identified 111 isolates, while 16S rRNA gene
sequencing was applied for the other 16 isolates, two of which could not be
associated with any previously described lactic acid bacteria (LAB) species.
Strain diversity was evaluated by phenotypic and random amplified polymorphic
DNA-PCR analysis. Molecular detection of Lactobacillus group species was
also performed on total DNA extracted from the doughs.
Conclusions: Abruzzo region sourdough lactobacilli biodiversity, reflected in
both Lactobacillus species composition and strain polymorphism, is similar to
that of other Italian regions and is a source of novel LAB species.
Significance and Impact of the Study: Within culture-independent methods,
multiplex PCR is a rapid tool to study the lactobacilli population of sourdoughs
Identification of subdominant lactic acid bacteria and their evolution during laboratory-scale fermentations
No full textPresumptive lactic acid bacterial cocci were found in six sourdoughs (out of 20) from the Abruzzo region (central Italy) and subjected
to phenotypic and genotypic characterization. A total of 21 isolates, recognized as seven strains by randomly amplified polymorphic
DNA (RAPD)–polymerase chain reaction (PCR) typing, were identified by a polyphasic approach, consisting of 16S rRNA gene
sequencing, multiplex PCR assays and physiological features, as Enterococcus faecium and Pediococcus pentosaceus. Four strains
belonging to those species and previously isolated from wheat kernels were inoculated in sterile flour to verify their capacity to grow in
sourdough environment. Doughs with several dual bacterial combinations, including Lactobacillus sanfranciscensis, were propagated for
11 days and pH measurements and bacterial counts were carried ou
Molecular approach for the rapid identification, in situ detection and monitoring of sourdough lactobacilli
No full textIdentification of subdominant sourdough lactic acid bacteria and their evolution during laboratory-scale fermentations
No full textEcologia microbica e caratteristiche fisico-chimiche di lieviti naturali della regione Abruzzo
No full textMonitoraggio della popolazione macrobiotica di paste acide prodotte nella regione Abruzzo
No full textSviluppo di un nuovo approccio molecolare per il monitoraggio dei lattobacilli degli impasti acidi della regione Abruzzo
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