CONICET | Buscador de Institutos y Recursos Humanos

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

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