Study on molecular identification of lactic acid bacteria from fermented milks and “Smen” (a traditional steppe butter) and their enzyme producing attributes

2019 ◽  
Vol 9 (3) ◽  
pp. 95-103
Author(s):  
Asmaa Labtar ◽  
Saliha Larouci ◽  
Amel Guermouche ◽  
Farid Bensalah
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Pcr Amplification ◽  
Titratable Acidity ◽  
Streptococcus Thermophilus ◽  
Fermented Milk ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Search Tool ◽  
Fermented Dairy

Streptococcus thermophilus and Lactobacillus belong to a widely-knowngroup of bacteria that have been frequently used as starter bacteria in fermented dairy products. The aim of this study was to isolate, characterize andidentify of lactic acid bacteria (LAB) from raw cow’s fermented milk and‘Smen’ (a traditional steppe butter) in steppic area of Algeria to study someof their important enzyme-producing attributes. All selected strains of lacticacid bacteria (LAB) were identified and typed by phenotypic and genotypiccriteria.Six strains were identified as cocci thermophilic LAB and two of themwere selected and identified by using polymerase chain reaction (PCR) amplification for proA gene. Six strains of lactobacilli were identified as Lactobacillus genus using 16S rRNA gene. Species identification was performed by 16SrRNA gene sequencing and sequences were analysed using Basic LengthAlignment Search Tool (BLAST) programs. A phylogenetic tree based on 16SrRNA genes was constructed by the neighbor-joinin method.S. thermophilusstrains screened for their ability to produce lactic acid, titratable acidity, andpH was measured at 2h intervals, proteolytic activity in milk was examined.In another part, the four selected Lactobacillus were able to hydrolyze X-Galby production of β-galactosidase enzyme. All strains of LAB exhibited production of diacetyl. Overall, this study provides bacterial strains having potentialfor dairy industry.

scholarly journals Biodiversity andγ-Aminobutyric Acid Production by Lactic Acid Bacteria Isolated from Traditional Alpine Raw Cow’s Milk Cheeses

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Elena Franciosi ◽  
Ilaria Carafa ◽  
Tiziana Nardin ◽  
Silvia Schiavon ◽  
Elisa Poznanski ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Random Amplified Polymorphic Dna ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Paracasei ◽  
Aminobutyric Acid ◽  
Cow’S Milk ◽  
Rrna Gene ◽  
Cow's Milk ◽  
Raw Cow’S Milk

“Nostrano-cheeses” are traditional alpine cheeses made from raw cow’s milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of “Nostrano-cheeses” and evaluated their potential to produceγ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n=97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated wereLactobacillus paracasei,Streptococcus thermophilus, andLeuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers wereLactobacillus paracaseibut other GABA producing species includedLactococcus lactis,Lactobacillus plantarum,Lactobacillus rhamnosus,Pediococcus pentosaceus, andStreptococcus thermophilus. NoEnterococcus faecalisorSc. macedonicusisolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was aSc. thermophilus.

scholarly journals Importância das Bactérias Ácido Láticas e não Starter (NSLAB) na Tecnologia de Produção dos Derivados Lácteos

2020 ◽  
Vol 24 (4) ◽  
pp. 348-352
Author(s):  
Maria Tereza Pereira ◽  
Elsa Helena Walter de Santana ◽  
Joice Sifuentes dos Santos
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactococcus Lactis ◽  
Lactobacillus Casei ◽  
Streptococcus Thermophilus ◽  
Raw Milk ◽  
Fermented Milk ◽  
Starter Cultures ◽  
Bacillus Spp ◽  
Lactobacillus Spp

Produtos lácteos fermentados contêm bactérias ácido lácticas (BAL), naturalmente presentes ou adicionadas na matriz láctea como culturas iniciadoras (starters), contribuindo com aroma, textura, valor nutricional e segurança microbiológica. Lactobacillus spp., Streptococcus spp., Lactococcus spp. e Leuconostoc spp. são utilizados como culturas starters em laticínios. As BAL podem ser classificadas em mesofílicas (ex Lactococcus lactis) e termofílicas (ex Streptococcus thermophilus), e de acordo com seus metabólitos de fermentação em homofermentativas (ácido lático) e heterofermentativas (ácido lático, dióxido de carbono, diacetil e outros compostos flavorizantes). Entre as BAL há um grupo de bactérias lácticas que não fazem parte da cultura láctica (non starter lactic acid bacteria - NSLAB), que são oriundas do leite cru, do ambiente de ordenha ou da indústria formando biofilmes. As NSLAB são representadas por espécies heterofermentativas de lactobacilos mesofílicos como Lactobacillus casei spp., L. paracasei spp., L. rhamnosus spp. e L. plantarum spp., e ainda por Pediococcus spp., Leuconostoc spp. e Micrococcus spp. NSLAB termoduricas como Bacillus spp. também são relatadas. As NSLAB em queijos podem ajudar a desenvolver sabor e aroma, porém também são associadas aos defeitos em queijos e leites fermentados. Problemas como odores estranhos, sabor amargo ou muito ácido, perda de viscosidade, perda de coloração, estufamento e formação de gás são associados com a presença e contaminação por NSLAB. Assim, as BAL são importantes micro-organismos na indústria láctea, garantindo sabores e aromas aos derivados. Já a presença de NSLAB podem ser associados com defeitos em queijos e leites fermentados, sendo um problema na indústria beneficiadora.   Palavras-chave: Característica Sensorial. Leites Fermentados. Queijo. Textura.                       Abstract Fermented dairy products contain acid bacteria (BAL) naturally present or added to the dairy matrix as starter cultures (starters), contributing to aroma, texture, nutritional value and microbiological safety. Lactobacillus spp., Streptococcus spp., Lactococcus spp. and Leuconostoc spp. are used as starter dairy crops. As BAL it can be classified as mesophilic (ex: Lactococcus lactis) and thermophilic (ex: Streptococcus thermophilus), and agree with its fermentation metabolites in homofermentative (lactic acid) and heterofermentative (lactic acid, carbon dioxide, diacetyl and other flavorings). Among the BAL, there is a group of lactic bacteria that are not part of the dairy culture (non-initiating lactic acid bacteria - NSLAB) that originate from raw milk, the milking environment or the biofilm-forming industry. NSLAB is represented by heterofermentative species of mesophilic lactobacilli such as Lactobacillus casei spp., L. paracasei spp., L. rhamnosus spp. and L. plantarum spp., and also by Pediococcus spp., Leuconostoc spp. and Micrococcus spp. Termoduric NSLAB such as Bacillus spp. are also related. NSLAB in cheeses may help develop flavor and aroma, and they are also associated with defects in fermented cheeses and milks. Problems such as strange odors, bitter or very acidic taste, loss of viscosity, loss of color, establishment and gas training are associated with the presence and contamination by NSLAB. Thus,  BALs are important microorganisms in the dairy industry, contributing to the dairy flavors and aromas. The presence of NSLAB, on the other hand, can be associated with defects in fermented milk and cheese, being a problem in the processing industry.   Keywords: Cheese. Fermented Milk. Sensory Characteristic. Texture.

scholarly journals A Novel qPCR Method for the Detection of Lactic Acid Bacteria in Fermented Milk

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3066
Author(s):  
Xiankang Fan ◽  
Xiefei Li ◽  
Tao Zhang ◽  
Jue Xu ◽  
Zihang Shi ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Fermented Milk ◽  
Confocal Laser ◽  
Quantitative Detection ◽  
Rrna Gene ◽  
Detection Range ◽  
Qualitative And Quantitative ◽  
Tuf Gene ◽  
Qpcr Method

The number of live lactic acid bacteria (LAB) is an important quality indicator for yogurt, the quantitative testing of LAB has become an important task in the evaluation of product quality and function. By analyzing and comparing the performance of 16S rRNA gene and tuf gene used in absolute quantification, the tuf gene with copy number 1 was selected as the target gene of six LAB. By drawing a standard curve to achieve qualitative and quantitative detection of six strains of LAB, the detection range was found to be 1 × 103–1 × 108 copies/µL. The traditional plate colony count and Flow Cytometry (FCM) were compared with the method of qPCR, which was used in this experiment. Meanwhile, the confocal laser microscope combined with STYO 9 and propidium iodide dyes was used to determine that the content of viable bacteria in the yogurt was more than 90%, which proved that the detection result using qPCR method was closer to the true level of LAB in yogurt. Compared with the existing methods, the method in this study allowed the qualitative and quantitative detection of the six kinds of LAB in yogurt, and the distribution of live and dead bacteria in yogurt could be calculated.

scholarly journals Potensi Beberapa Susu Fermentasi Komersial Sebagai Antifungi Candida albicans

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Nur Khikmah Nunung Sulistyani
Keyword(s):  
Candida Albicans ◽  
Lactic Acid ◽  
Antifungal Activity ◽  
Lactic Acid Bacteria ◽  
Fermented Milk ◽  
Plate Count ◽  
Diffusion Method ◽  
Milk Products ◽  
Fermented Dairy ◽  
Fermented Milk Products

Candida albicans cause opportunistic infection of the oral cavity. Probiotic has health benefits, produces organic acids as anti-C. albicans. The aim of this research was to determine the antifungal activity of commercial fermented milk products against Candida and viability of bacteria in commercial fermented milk products. The antifungal activity was determined using well diffusion method. Viability of lactic acid bacteria was done by plate count method. The results show that commercial fermented milk productshas an activity of anti-C.albicans were shown by irradical zone formed around well containing fermented dairy products. Viability of lactic acid bacteria 107-1010 CFU/mL.

scholarly journals Tracking of Intentionally Inoculated Lactic Acid Bacteria Strains in Yogurt and Probiotic Powder

2019 ◽  
Vol 8 (1) ◽  
pp. 5 ◽  
Author(s):  
Anshul Sharma ◽  
Jasmine Kaur ◽  
Sulhee Lee ◽  
Young-Seo Park
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gene Sequence ◽  
Random Amplified Polymorphic Dna ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Sequence Alignments ◽  
Gene Sequence Analysis ◽  
Rrna Gene Sequencing

The present work aimed at tracking intentionally inoculated lactic acid bacteria (LAB) strains in yogurt and probiotic powder. Leuconostoc (Leu.) mesenteroides (11251), Lactobacillus (L.) brevis (B151), and Lactobacillus plantarum (LB41K) strains were tracked in yogurt, and L. plantarum (LB41P) was tracked in a commercial probiotic powder. The yogurt was intentionally inoculated with the selected bacterial strains. Two types of yogurt with known and unknown bacterial pools were utilized. The standard 16S rRNA gene sequencing was used to evaluate the initial screening. The molecular typing tools, random amplified polymorphic DNA (RAPD), repetitive element palindromic PCR (rep-PCR), and comparative gene sequence analysis of selected housekeeping loci were used to track the inoculated dubious strains. Out of 30 random selections for each inoculation, the developed method identified seven (11251), nine (B151), and five (LB41K) colonies in the yogurt. The validation was performed by identifying 7 colonies (LB41P) out of 30 in the probiotic powder. The DNA banding profiles and the gene sequence alignments led to the identification of the correct inoculated strains. Overall, the study summarizes the use of molecular tools to identify the deliberately inoculated LAB strains. In conclusion, the proposed polyphasic approach effectively tracked the intentionally inoculated strains: Leu. mesenteroides, L. brevis, and L. plantarum (LB41K) in yogurt and L. plantarum (LB41P) in probiotic powder. The study demonstrates how to track industrially relevant misused LAB strains in marketable food products.

scholarly journals Identifying the Diversity of Dominant LABs from Fermented Dairy Products Dahi and Yoghurt in Eastern Region of Nepal

2019 ◽  
Vol 11 ◽  
pp. 60-64
Author(s):  
Sanjay Mahato ◽  
Aakash Kumar Shahani
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Eastern Region ◽  
Isolation And Identification ◽  
Carbohydrate Utilization ◽  
Variable Nature ◽  
Microbiological Techniques ◽  
Fermented Dairy

The aim of this study was to isolate and identify lactic acid bacteria diversity from dahi/ yoghurt. Curd, also known as commercially prepared yoghurt or homemade Dahi, is formed during the slow lactic fermentation of lactose from milk by thermophilic lactic acid bacteria (LAB). Thirty-five samples of yoghurt and curd were collected from the Biratnagar and isolation and identification of bacteria were done by various microbiological techniques like MRS Agar inoculation, colony characteristics, microscopic and biochemical examination. A total of sixty-six strains of lactobacilli were isolated from curd and identification of strains was done by biochemical and carbohydrate utilization test. Lactobacillus bulgaricus, L. casei, L. fermentum, L. acidophilus, and Streptococcus thermophilus were identified from curd. pH of samples was between 3.0 to 4.0 for homemade dahi; while 4.34 to 4.5 for commercially available yoghurt. The mean colony count of lactic acid bacteria was 1.4x107–4.9x107 cfu/g. 37.9% of samples contained Streptococcus thermophilus, 30.3% had Lactobacillus bulgaricus. Forty-five isolates from 24 industrial yoghurt samples showed 37.5% of the yoghurt contained both Lactobacillus bulgaricus and Streptococcus thermophilus followed by 25% samples having S. thermophilus and L. acidophilus. Other species like L. fermentum and L. casei were less common. From 11 homemade dahi samples, 54.5% of curd possessed both S. thermophilus and L. bulgaricus; 18.2% curd had both S. thermophilus and L. fermentum. The study concludes that L. bulgaricus and Streptococcus thermophilus are prevalent potent lactic acid bacteria. This study provides an account of the diversity of lactic acid bacteria in dahi/ yoghurt which will provide useful information about the variable nature of curd in this region to future researchers.

scholarly journals Clustering of Streptococcus thermophilus Strains to Establish a Relation between Exopolysaccharide Characteristics and Gel Properties of Acidified Milk

Foods ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 146 ◽  
Author(s):  
Georg Surber ◽  
Susann Mende ◽  
Doris Jaros ◽  
Harald Rohm
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Streptococcus Thermophilus ◽  
Starter Cultures ◽  
Extracellular Polysaccharides ◽  
Gel Properties ◽  
Fermentation Time ◽  
Thread Length ◽  
Acid Gel ◽  
Fermented Dairy

In situ produced extracellular polysaccharides (EPS) from lactic acid bacteria are generally known to affect the texture of fermented dairy products; however, the interplay between EPS and product properties is still poorly understood. The aim of this study was to establish a relationship between concentration and properties of EPS, and gel formation of milk analysed by noninvasive Multispeckle Diffusing Wave Spectroscopy. Twenty Streptococcus thermophilus strains were classified with respect to EPS concentration (8–126 mg GE/kg) and ropiness (thread length: 15–80 mm). Five groups identified by cluster analysis demonstrate the high strain-to-strain variability even within one species of lactic acid bacteria. Results from acidification and gelation experiments averaged per cluster indicate that fermentation time and gel stiffness is higher for strains that produce ropy EPS. A further increase in gel stiffness was detected for strains that also produced cell-bound EPS, which underlines the importance of both ropy and cell-bound EPS for improving acid gel properties. The results may be helpful for a proper selection of EPS-producing starter cultures.

scholarly journals Animal Rennets as Sources of Dairy Lactic Acid Bacteria

2014 ◽  
Vol 80 (7) ◽  
pp. 2050-2061 ◽  
Author(s):  
Margherita Cruciata ◽  
Ciro Sannino ◽  
Danilo Ercolini ◽  
Maria L. Scatassa ◽  
Francesca De Filippis ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Streptococcus Thermophilus ◽  
Species Level ◽  
Lactobacillus Delbrueckii ◽  
Rrna Gene ◽  
Microbial Composition ◽  
Content Type

ABSTRACTThe microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB),Streptococcus thermophilusand some lactobacilli, mainlyLactobacillus crispatusandLactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, asEnterococcus casseliflavus,Enterococcus faecium,Enterococcus faecalis,Enterococcus lactis,Lactobacillus delbrueckii, andStreptococcus thermophilus, while the other strains, all belonging to the genusEnterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions.

scholarly journals Selection of Lactic Acid Bacteria for the Optimized Production of Sheep’s Milk Yogurt with a High Conjugated Linoleic Acid Content

2017 ◽  
Vol 6 (4) ◽  
pp. 44 ◽  
Author(s):  
Gabriela Christina Kuhl ◽  
Ana Paula Gusso ◽  
Brenda Lee Simas Porto ◽  
Carmen Maria Olivera Müller ◽  
Ricardo Ruiz Mazzon ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Linoleic Acid ◽  
Lactic Acid Bacteria ◽  
Conjugated Linoleic Acid ◽  
Streptococcus Thermophilus ◽  
Linoleic Acid Content ◽  
Fractional Factorial ◽  
Lactobacillus Delbrueckii ◽  
Bacterial Strains ◽  
Sheep Milk

Thirty-five different lactic acid bacteria (LAB) strains were screened for their conjugated linoleic acid (CLA) isomers (C18:2 cis-9, trans-11 and C18:2 trans-10, cis-12) producing ability from linoleic acid (LA) in sheep’s milk. Preliminary experiments revealed that Lactobacillus delbrüeckii ssp. bulgaricus 2230 and Streptococcus thermophilus St 360 among the screened strains had the highest CLA-producing ability. This two strains were assayed in an 11-run fractional factorial design to investigate the effect of four variables included glucose, powdered sheep milk, LA and inoculum ratio on CLA production in a sheep’s milk yogurt. The optimum conditions for producing the highest levels of CLA (42.86%) were obtained by adding 10.00 mg/mL of glucose, 30.00 mg/mL of powdered sheep milk, 0.90 mg/mL of LA and a 1:2 (St:Lb) ratio of bacterial strains in the inoculum. This CLA-rich sheep’s milk yogurt could be an important supplementary food source for increasing the CLA in the human diet. 

A PCR Assay for Detection of Acetic Acid–Tolerant Lactic Acid Bacteria in Acidic Food Products

2004 ◽  
Vol 67 (3) ◽  
pp. 610-615 ◽  
Author(s):  
SHIGERU NAKANO ◽  
ATSUSHI MATSUMURA ◽  
TOSHIHIRO YAMADA
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Enrichment Culture ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Pcr Assay ◽  
Acid Tolerant

A PCR assay for the detection of acetic acid–tolerant lactic acid bacteria in the genera of Lactobacillus and Pediococcus was developed in this study. Primers targeting the bacterial 16S rRNA gene were newly designed and used in this PCR assay. To determine the specificity of the assay, 56 different bacterial strains (of 33 genera), 2 fungi, 3 animals, and 4 plants were tested. Results were positive for most tested bacterial members of 16S rRNA gene–based phylogenetic groups (classi ed in the Lactobacillus casei and Pediococcus group), including Lactobacillus fructivorans, Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus plantarum, and Lactobacillus paracasei. For all other bacterial strains and eukaryote tested, results were negative. Bacterial DNA for PCR was prepared with a simple procedure with the use of Chelex 100 resin from culture after growth in deMan Rogosa Sharpe broth (pH 6.0). To test this PCR assay for the monitoring of the acetic acid–tolerant lactic acid bacteria, L. fructivorans was inoculated into several acidic food as an indicator. Before the PCR, the inoculation of 10 to 50 CFU of bacteria per g of food was followed by a 28-h enrichment culture step, and the PCR assay allowed the detection of bacterial cells. Including the enrichment culture step, the entire PCR detection process can be completed within 30 h.

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