Application of unsupervised clustering algorithm and heat-map analysis for selection of lactic acid bacteria isolated from dairy samples based on desired probiotic properties

Objective: The aim of this research was to isolate and identify lactic acid bacteria using 16S rRNA and evaluates their potential as probiotics.Methods: The probiotic properties measured were resistance to low pH and to 0.3% and 0.5% bile salts, antimicrobial activity against pathogenic bacteria (Escherichia coli O157:H7 and Staphylococcus aureus ATCC 25923), antibiotic resistance, and hydrophobicity.Results: The lactic acid bacteria with optimal probiotic properties were isolated from buffalo milk and identified from a sample from Agam district (BMA 3.3) which was classified using BLAST analysis as a strain of Lactobacillus fermentum (L23). Conclusion: Buffalo milk from this part of West Sumatera contains a strain of L. fermentum with has good probiotic properties.

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Lactic Acid Bacteria From Saltwater Fish Samples: Probiotic Potential Characterization and Clustering Using Unsupervised Algorithms

10.21203/rs.3.rs-1106400/v1 ◽

2021 ◽

Author(s):

Atefeh Mazlomi ◽

Bahman Panahi ◽

Yousef Nami

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Probiotic Properties ◽

Gi Tract ◽

Heat Map ◽

Probiotic Potential ◽

Saltwater Fish ◽

Fish Samples ◽

Variable Sensitivity ◽

Unsupervised Algorithms

Abstract This research aimed to isolate lactic acid bacteria (LAB) from the bowl of saltwater fish to assess their probiotic properties. Nineteen isolates of LAB including Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus fermentum, Lactococcus lactis, Enterococcus hirae, Enterococcus lactis, Pediococcus pentosaceus, Pediococcus acidilactici, and Pediococcus lolli were recognized using molecular tools. All the isolates survived in the simulated conditions of the GI tract. Auto-aggregation ranged from 01.3 ± 0.5% to 82.6 ± 1.4% and hydrophobicity with toluene ranged from 3.7 ± 1.6% to 69.4 ± 1.3%, while the range of hydrophobicity with xylene was from 02.2 ± 1.6% to 56.4 ± 2.1%. All the isolates of lactobacilli, pediococci, enterococci, and lactococci indicated variable sensitivity and resistance towards clinical antibiotics. Non-neutralized cell free supernatant of isolates F12 and F15 showed antimicrobial activity against all the 8 evaluated enteric pathogens. Cluster analysis of identified potential probiotic bacteria based on heat-map and PCA methods also highlighted the priority of isolates F3, F7, F12, and F15 as bio-control agents in fishery industry. The findings of this study may essentially contribute to the understanding of the probiotic potential of LAB in saltwater fish, in order to access their probiotic characterization for use as biocontrol in fishery.

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Isolation and Characterization of Lactic Acid Bacteria and Yeasts from Typical Bulgarian Sourdoughs

Microorganisms ◽

10.3390/microorganisms9071346 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1346

Author(s):

Mariana Petkova ◽

Petya Stefanova ◽

Velitchka Gotcheva ◽

Angel Angelov

Keyword(s):

Lactic Acid ◽

Sequence Analysis ◽

Lactic Acid Bacteria ◽

Antimicrobial Properties ◽

Matter Content ◽

Starter Cultures ◽

Rrna Gene ◽

Dry Matter Content ◽

Isolation And Characterization ◽

Selection Of

Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products.

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Microbiological and Chemical Properties of Chokeberry Juice Fermented by Novel Lactic Acid Bacteria with Potential Probiotic Properties during Fermentation at 4 °C for 4 Weeks

Foods ◽

10.3390/foods10040768 ◽

2021 ◽

Vol 10 (4) ◽

pp. 768

Author(s):

Christos Bontsidis ◽

Athanasios Mallouchos ◽

Antonia Terpou ◽

Anastasios Nikolaou ◽

Georgia Batra ◽

...

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Chemical Properties ◽

Storage Period ◽

Probiotic Strain ◽

Physicochemical Characteristics ◽

Probiotic Properties ◽

Acid Fermentation ◽

Chokeberry Juice ◽

Fermented Juice

On the frame of this research survey, a novel potentially probiotic strain (Lactobacillus paracasei SP5) recently isolated from kefir grains was evaluated for chokeberry juice fermentation. Chokeberry juice was retrieved from the variety Aronia melanocarpa, a plant known to provide small, dark berries and to be one of the richest sources of antioxidants. The juice was subsequently fermented inoculating L. paracasei SP5 for 48 h at 30 °C. The fermented juices were left at 4 °C and tested regarding microbiological and physicochemical characteristics for 4 weeks. The potentially probiotic strain was proved capable of performing lactic acid fermentation at 30 °C. Cell viability of L. paracasei was detected in high levels during fermentation and the whole storage period, while the fermented juice showed higher levels of viability in juice with 40.3 g/L of initial sugar concentration. No ethanol was detected in the final fermented juice. Fermented chokeberry juice was characterized by aromatic desirable volatiles, which were retained in adequate levels for the whole storage period. Specifically, the occurrence of organic esters detected in fermented juices is considered as positive evidence of the provision of fruity and floral notes to the final product. During storage, total phenolics content and antioxidant activity were observed in higher levels in fermented chokeberry juice compared with non-fermented juice. Subsequently, fermentation of chokeberry juice by potentially probiotic lactic acid bacteria could provide high industrialization potential, providing the market with a nutritional beverage of good volatile quality with an enhanced shelf-life compared with an unfermented fresh juice.

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