INVESTIGADORES
VIGNOLO Graciela Margarita
congresos y reuniones científicas
Título:
Molecular characterization of lactic acid bacteria isolated from « tunta » production chain
Autor/es:
SANTOS MENDOZA, RICARDO; RAMOS VÁZQUEZ, ELENA; VIGNOLO, GRACIELA; ZÚÑIGA DÁVILA, DORIS
Lugar:
San Miguel de Tucuman
Reunión:
Simposio; IV International Symposium on Lactic Acid Bacteria: Food, Health and Applications; 2013
Institución organizadora:
CERELA-CONICET
Resumen:
The tunta, is a fermented food which is made from naturally lyophilized native potatoes. Its
resistance to weather and high caloric content, higher than fresh potatoes, make it a strategic
product in the fragile economy of the Altiplano. Puno region (south‐East Peru) accounts for about
70% tunta production in the country and actually, an estimated 6000 tonnes of this product is
traded annually. Because there is not enough information of microbial populations in native
products or natural fermented foods, this study aims to molecularly characterize isolates of lactic
acid bacteria (LAB) and determine their phylogenetic affiliations. The study area was located in
Ilave river basin, province of El Collao, southern Puno, with temperatures ranging from 1 ‐ 15 °C
and average annual rainfall of around 620 mm. Two sampling were carried out in different steps
within the production chain of tunta. Samples of raw materials, native potatoes immersed in the
river for processing into tunta and final product were taken. Quantification and isolation of LAB was
performed under aerobic and anaerobic conditions, in Man, Rogosa & Sharpe (MRS) media
supplemented with different sugars and yeast glucose lactose peptone agar (YGLP). The
confirmation of presumptive colonies was given by Gram staining and catalase tests. Isolation of
126 strains was achieved, they have been stored in 25% glycerol at ‐80 °C.. After performing the
molecular characterization of 52 LAB strains by BOX‐PCR amplification (Versalovic et al. 1991) and
16S ribosomal gene sequencing, it was determined that isolates belong to the genera Lactobacillus
and Leuconostoc. Eighteen strains showed 99.71% similarity to Lactobacillus curvatus LMG 9198T
[AJ621550]. Five were classified into the cluster including L. curvatus LMG 9198T [AJ621550] and L.
graminis DSM 20719T [AM113778]. Four strains were identified as Lactobacillus sakei subsp. sakei
DSM 20017T [AY204893] (100% similarity) and other as Lactobacillus brevis ATCC 14687T
[EF120367] (100% similarity). Likewise, two of the strains were identified characterized (100%
similarity) and Leuconostoc mesenteroides subsp. dextranicum NRIC 1539T [AB023246] and 1 was
associated with a 99.93% similarity to Leuconostoc mesenteroides subsp. mesenteroides ATCC
8293T [NR 074 957]. Furthermore, two of characterized strains were identified (100% similarity) as
Leuconostoc mesenteroides subsp. dextranicum NRIC 1539T [AB023246] and one was related to
Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293T [NR 074 957] with 99.93% similarity.
Assays evaluating bacteriocin‐producing capacity of the strains reflect that 41% of isolates inhibited
the growth of Listeria innocua and 1% inhibited the growth of Lactobacillus plantarum. Strains were
found in this study have been previously reported as bacteriocin producers and antimicrobial
compounds, others could be also used as bio‐thickeners and even have probiotic properties. This
research aims to revaluate the biotechnological importance of LAB from native Andean products,
taking advantage of their qualities in nutritional and hygienic improvements and quality food, for
industrial and pharmaceutical industries. In a second stage of this study, the functional and
probiotic properties of isolates and their possible importance for industry will be identified