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1.
Int J Food Microbiol ; 322: 108547, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32097827

RESUMO

The present study aimed to characterize lactic acid bacteria involved in the different processing steps of tchapalo, a traditional Ivoirian beverage, for their potential application as starter cultures in food and beverages. Lactic acid bacteria (LAB) were therefore isolated and enumerated at different steps of the process on MRS and BEA agars. Of the 465 isolates, 27 produced bacteriocins that inhibit Lactobacillus delbrueckii F/31 strain. Of those, two also inhibited Listeria innocua ATCC 33090, while two others displayed inhibitory activity against L.innocua ATCC 33090, E. faecalis CIP 105042, E. faecalis ATCC 29212, Streptococcus sp. clinical LNSP, E. faecalis CIP 105042 and E. faecium ATCC 51558. The dominant species involved in tchapalo LAB fermentation, as determined by 16S rRNA gene sequencing, were Lactobacillus fermentum (64%), followed by Pediococcus acidilactici (14%). Two strains representing the two dominant species, L. fermentum S6 and P. acidilactici S7, and two potential bacteriocin producers, Weissella confusa AB3E41 and Enterococcus faecium AT1E22, were selected for further characterization. First, genome analysis showed that these strains do not display potential harmful genes such as pathogenic factors or transmissible antibiotic resistance genes. Furthermore, phylogenetic analyses were performed to assess evidence of eventual links to groups of strains with particular properties. They revealed that (i) L. fermentum S6 and P. acidilactici S7 are closely related to strains that ferment plants, (ii) E. faecium AT1E22 belongs to the environmental clade B of E. faecium, while W. confusa is quite similar to other strains also isolated from plant fermentations. Further genome analysis showed that E. faecium AT1E22 contains the Enterocin P gene probably carried by a megaplasmid, whereas no evidence of a bacteriocin gene was found in W. confusa AB3E41. The metabolic and the first step of the probiotic potentials of the different strains were analyzed. Lactobacillus fermentum S6 and P. acidilactici S7 are good candidates to develop starter cultures, and E. faecium AT1E22 should be further tested to confirm its potential as a probiotic strain in the production of sorghum wort.


Assuntos
Cerveja/microbiologia , Lactobacillales/isolamento & purificação , Sorghum/microbiologia , Bacteriocinas/genética , Bacteriocinas/metabolismo , Fermentação , Genoma Bacteriano/genética , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/metabolismo , Listeria/crescimento & desenvolvimento , Filogenia , Probióticos/classificação , Probióticos/metabolismo , RNA Ribossômico 16S/genética
2.
Arch Microbiol ; 202(4): 875-885, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31894393

RESUMO

The objective of this study was to assess the effects of some culture conditions [temperature (20, 30, 37 °C), incubation time (48, 72, 120 h), pH (5.0, 6.0, 7.0), NaCl concentration (0, 3, 6%), carbon (glucose, fructose, lactose), nitrogen (sodium nitrate, ammonium sulfate, bacto-peptone), and mineral sources (calcium carbonate, ferric chloride)] on the exopolysaccharide (EPS) production by lactic acid bacteria (LAB) strains (belonging to Lactobacillus (L.) plantarum, L. namurensis, and Pediococcus (P.) ethanolidurans species) isolated from naturally fermented pickles. The maximum EPS production was determined at 30 °C and pH 6.0. The highest amount of EPS was obtained after 120 h of incubation, with glucose as carbon source, bacto-peptone as nitrogen source and calcium carbonate as mineral source for most of the tested strains. The EPS formation was not stimulated by NaCl, indicating that EPS formation of the tested strains was not a stress response. L. plantarum MF460 produced the highest amount of EPS at 30 °C after 48 h of incubation, which was 515.48 mg/L. One of the most pronounced results of this study was that the EPS production of L. plantarum MF556 strain was increased up to 512.81 mg/L with the addition of calcium carbonate to MRS medium. The effect of different culture conditions, particularly of incubation time, carbon, nitrogen, and mineral sources, on the EPS production often vary depending on the strain. Therefore, these apparent strain specific results demonstrated that the optimum culture conditions for the enhanced EPS production should be specifically determined for each LAB strain.


Assuntos
Meios de Cultura/farmacologia , Alimentos e Bebidas Fermentados/microbiologia , Microbiologia de Alimentos , Lactobacillales/efeitos dos fármacos , Lactobacillales/metabolismo , Polissacarídeos Bacterianos/biossíntese , Fermentação , Lactobacillales/isolamento & purificação , Temperatura
3.
Food Microbiol ; 87: 103385, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948626

RESUMO

The present work was carried out to evaluate the microbiological and physicochemical composition of salamis produced with the meat of beef, horse, wild boar and pork. Salami productions occurred under controlled laboratory conditions to exclude butchery environmental contaminations, without the addition of nitrate and nitrite. All trials were monitored during the ripening (13 °C and 90% relative humidity) extended until 45 d. The evolution of physicochemical parameters showed that beef and pork salamis were characterized by a higher content of branched chain fatty acids (FA) and rumenic acid than horse and wild boar salamis, whereas the last two productions showed higher values of secondary lipid oxidation. Plate counts showed that lactic acid bacteria (LAB), yeasts and coagulase-negative staphylococci (CNS) populations dominated the microbial community of all productions with Lactobacillus and Staphylococcus as most frequently isolated bacteria. The microbial diversity evaluated by MiSeq Illumina showed the presence of members of Gammaproteobacteria phylum, Moraxellaceae family, Acinetobacter, Pseudomonas, Carnobacterium and Enterococcus in all salamis. This study showed the natural evolution of indigenous fermented meat starter cultures and confirmed a higher suitability of horse and beef meat for nitrate/nitrite free salami production due to their hygienic quality at 30 d.


Assuntos
Alimentos e Bebidas Fermentados/microbiologia , Produtos da Carne/microbiologia , Animais , Bovinos , Fermentação , Alimentos e Bebidas Fermentados/análise , Microbiologia de Alimentos , Cavalos , Lactobacillales/genética , Lactobacillales/crescimento & desenvolvimento , Lactobacillales/isolamento & purificação , Produtos da Carne/análise , Carne Vermelha/microbiologia , Staphylococcus/genética , Staphylococcus/crescimento & desenvolvimento , Staphylococcus/isolamento & purificação , Sus scrofa , Suínos
4.
J Sci Food Agric ; 100(4): 1448-1457, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31756265

RESUMO

BACKGROUND: Baixi sufu (BS) is a traditional Chinese spicy fermented bean curd manufactured with a natural starter. In this study, the bacterial and fungal communities during BS fermentation were determined by culture and by the culture-independent method of high-throughput sequencing (HTS). Correlation analyses were performed to select the microorganisms potentially contributing to this fermentation. RESULTS: During the fermentation of BS, 162 bacterial and 97 fungal strains were isolated and identified, and a total of 268 314 bacterial and 287 844 fungal high-quality sequences were analyzed. In general, lactic acid bacteria (LAB), especially Enterococcus and Lactococcus, were dominant in the early stage of fermentation, and spore-forming bacteria, especially Bacillus spp., became the predominant bacteria by the end of fermentation. Geotrichum, Mortierella, and unclassified Ascomycota, were the major fungal populations, which could not be detected in the final product. Correlation analyses indicated that Enterococcus, Bacillus, Geotrichum, and unclassified Ascomycota correlated significantly and positively with amino nitrogen. However, due to the sporulation characteristics of Bacillus, they may have little effect on BS ripening. The presence of Bifidobacterium spp. in sufu is reported for the first time, but the excessive counts of the Bacillus cereus group (>105 CFU g-1 ) indicate a potential hazard to consumers. CONCLUSION: The profiles obtained from this study will contribute to the development of autochthonous starter cultures to control BS fermentation, and may lead to the development of novel strategies to shorten the fermentation time of sufu products. © 2019 Society of Chemical Industry.


Assuntos
Fabaceae/microbiologia , Fungos/metabolismo , Lactobacillales/metabolismo , Micobioma , Fabaceae/metabolismo , Fermentação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação
5.
J Dairy Sci ; 103(1): 141-149, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31629528

RESUMO

The objective of this study was to develop a novel immobilized system using kefir lactic acid bacteria and sugar cane pieces for the production of fermented milk. Lactobacillus kefiranofaciens HL1, Lactobacillus kefiri HL2, Leuconostoc mesenteroides HL3, and Lactococcus lactis HL4 were isolated from Taiwanese kefir grains and immobilized on pieces of sugar cane using adsorption. Scanning electron micrographs of the cell-immobilized sugar cane pieces (CISCP) showed that the microorganisms were embedded within the porous structures of the sugar cane pieces. During 28 cycles of repeated batch fermentation, viable cells on both sugar cane pieces and fermented products were maintained at 10 log cfu/g (cfu/mL). Random amplified polymorphic DNA PCR analysis revealed that Leu. mesenteroides HL3 (29-43%) and Lc. lactis HL4 (31-49%) were predominant on the CISCP, and the fermented samples had 79% Lc. lactis HL4. When tracking fermentation parameters, the data on the microbial, chemical, and physical properties of the fermented milk suggested that the CISCP had stable fermentative ability over the course of successive fermentations. We found an enhancement of the acid-producing ability of CISCP as the number of fermentations increased, with a significant growth in titratable acidity from 0.65 to 0.81% by the end.


Assuntos
Produtos Fermentados do Leite/microbiologia , Kefir/microbiologia , Lactobacillales/metabolismo , Lactobacillus/isolamento & purificação , Leite/metabolismo , Saccharum , Animais , Células Imobilizadas , Fermentação , Lactobacillales/isolamento & purificação , Lactococcus lactis/isolamento & purificação , Lactococcus lactis/metabolismo , Leuconostoc/isolamento & purificação , Leite/química
6.
J Dairy Sci ; 103(2): 1238-1249, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31864732

RESUMO

Cheese is a fermented dairy product that is popular for its unique flavor and nutritional value. Recent studies have shown that microorganisms in cheese play an important role in the fermentation process and determine the quality of the cheese. We collected 12 cheese samples from different regions and studied the composition of their bacterial communities using PacBio small-molecule real-time sequencing (Pacific Biosciences, Menlo Park, CA). Our data revealed 144 bacterial genera (including Lactobacillus, Streptococcus, Lactococcus, and Staphylococcus) and 217 bacterial species (including Lactococcus lactis, Streptococcus thermophilus, Staphylococcus equorum, and Streptococcus uberis). We investigated the flavor quality of the cheese samples using an electronic nose system and we found differences in flavor-quality indices among samples from different regions. We found a clustering tendency based on flavor quality using principal component analysis. We found correlations between lactic acid bacteria and the flavor quality of the cheese samples. Biodegradation and metabolism of xenobiotics, and lipid-metabolism-related pathways, were predicted to contribute to differences in cheese flavor using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). This preliminary study explored the bacterial communities in cheeses collected from different regions and their potential genome functions from the perspective of flavor quality.


Assuntos
Bactérias/isolamento & purificação , Queijo/microbiologia , Variação Genética , Bactérias/classificação , Bactérias/genética , Queijo/análise , DNA Bacteriano/análise , Microbiologia de Alimentos , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Lactobacillus/genética , Lactobacillus/isolamento & purificação , Lactococcus lactis/genética , Lactococcus lactis/isolamento & purificação , Filogenia , Análise de Sequência de DNA , Streptococcus/genética , Streptococcus/isolamento & purificação , Streptococcus thermophilus/genética , Streptococcus thermophilus/isolamento & purificação
7.
Food Chem ; 306: 125620, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31606627

RESUMO

The lactic acid bacteria (LAB) and yeast strains with phytate degrading ability were isolated from Iranian traditional sourdough, and based on the acid and bile tolerance, three LAB and three yeast strains were selected and molecularly identified. In this study, baker's yeast (Saccharomyces cerevisiae) was considered as a positive control strain to investigate the nutritional and technological properties of the isolated strains. All of the identified microorganisms were characterized based on additional probiotic properties and were evaluated for nutritional and technological characteristics. The functional features are associated with degradation of phytate, antioxidant capacity, exopolysaccharides, phenolic compound content and in vitro starch digestion. Among all the tested strains the highest amount of phytase production capacity (1.64 Unit/ml) and lowest phytate content (17.49 mg/5 g) belonged to Kluyveromyces marxianus. According to the results, the bread prepared by using Kluyveromyces aestuarii possessed the highest porosity percentage (70.43%), and the lowest hardness (508.71 g).


Assuntos
Pão/análise , Lactobacillales/metabolismo , Ácido Fítico/metabolismo , Saccharomyces cerevisiae/metabolismo , Triticum/química , 6-Fitase/metabolismo , Pão/microbiologia , Irã (Geográfico) , Lactobacillales/isolamento & purificação , Probióticos , Saccharomyces cerevisiae/isolamento & purificação , Triticum/metabolismo
8.
Lett Appl Microbiol ; 70(1): 48-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31642537

RESUMO

This study aims to describe the native microbiota of fermented spelt, taking into consideration both lactic acid bacteria (LAB) and yeasts, for which little data are available. Five samples of commercial spelt flour were subjected to spontaneous fermentation to obtain a type I sourdough. A total of 186 LAB and 174 yeast isolates were selected at different refreshment steps and subjected to further analyses. Within LAB, coccal isolates constituted 78·5% of the total LAB, with the dominance of Pediococcus pentosaceus. Although documented before as a component, this is the first report of a spelt sourdough fermentation dominated by this homofermentative LAB, characterized by a high acidification rate, ability to utilize a wide range of carbon sources and to grow in high osmolarity conditions. Yeast communities resulted in four dominant species, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Pichia fermentans and Clavispora lusitaniae. This study highlights for the first time the biodiversity and dynamics of yeast communities involved in sourdough fermentation of spelt. Compared to commercial baker's yeast, autochthonous W. anomalus, P. fermentans and S. cerevisiae isolates show a good performance, and their use could be an advantage for their acquired adaptation to the environment, providing stability to the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: Nowadays, there is a renewed interest in products based on spelt. This 'ancient grain' is a highly nutritional grain; however, its use is limited to bread-making processes, which are not standardized. The low baking and sensory quality of spelt can be overcome through fermentation processes. However, the autochthonous microbiota of spelt sourdough is poorly known. This study highlights the dynamics of microbial communities involved in sourdough fermentation of spelt and provides the basis for the selection of autochthonous cultures, with the aim of improving the nutritional potential of spelt and its rheology and bread-making properties.


Assuntos
Pão/microbiologia , Lactobacillales/metabolismo , Consórcios Microbianos , Triticum/microbiologia , Leveduras/metabolismo , Biodiversidade , Pão/análise , Fermentação , Farinha/microbiologia , Microbiologia de Alimentos , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Triticum/metabolismo , Leveduras/classificação , Leveduras/genética , Leveduras/isolamento & purificação
9.
Int J Mol Sci ; 20(20)2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31600952

RESUMO

Biotransformation via solid state fermentation (SSF) mediated by microorganisms is a promising approach to produce useful products from agricultural biomass. Lactic acid bacteria (LAB) that are commonly found in fermented foods have been shown to exhibit extracellular proteolytic, ß-glucosidase, ß-mannosidase, and ß-mannanase activities. Therefore, extracellular proteolytic, cellulolytic, and hemicellulolytic enzyme activities of seven Lactobacillus plantarum strains (a prominent species of LAB) isolated from Malaysian foods were compared in this study. The biotransformation of palm kernel cake (PKC) biomass mediated by selected L. plantarum strains was subsequently conducted. The results obtained in this study exhibited the studied L. plantarum strains produced versatile multi extracellular hydrolytic enzyme activities that were active from acidic to alkaline pH conditions. The highest total score of extracellular hydrolytic enzyme activities were recorded by L. plantarum RI11, L. plantarum RG11, and L. plantarum RG14. Therefore, they were selected for the subsequent biotransformation of PKC biomass via SSF. The hydrolytic enzyme activities of treated PKC extract were compared for each sampling interval. The scanning electron microscopy analyses revealed the formation of extracellular matrices around L. plantarum strains attached to the surface of PKC biomass during SSF, inferring that the investigated L. plantarum strains have the capability to grow on PKC biomass and perform synergistic secretions of various extracellular proteolytic, cellulolytic, and hemicellulolytic enzymes that were essential for the effective biodegradation of PKC. The substantial growth of selected L. plamtraum strains on PKC during SSF revealed the promising application of selected L. plantarum strains as a biotransformation agent for cellulosic biomass.


Assuntos
Biomassa , Biotransformação , Celulose/metabolismo , Microbiologia de Alimentos , Lactobacillales/metabolismo , Phoeniceae/química , Biodegradação Ambiental , Celulose/química , Espaço Extracelular/metabolismo , Fermentação , Hidrólise , Lactobacillales/isolamento & purificação , Proteólise
10.
Anal Sci ; 35(10): 1065-1067, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31495815

RESUMO

We have reported a simple method for separating lactic acid bacteria (LAB) from yogurt. This method is based on the process of destructions and denaturation of casein micelle aggregates by vortexing, and can supply samples containing only LAB. Recovered LAB were clearly observable by microscopy, meaning that morphological changes could be directly detected at the single-cell level. This method will be a helpful tool for the analyzing various LAB, including their enzyme activity and protein expression.


Assuntos
Lactobacillales/isolamento & purificação , Iogurte/microbiologia , Caseínas/química , Micelas , Fatores de Tempo
11.
Curr Microbiol ; 76(10): 1095-1104, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31270565

RESUMO

Fermented cereals are part of the main traditional diets of many people in Africa, usually obtained from artisanal production. The intensification of their manufacturing, responding to the consumers demand, requires a better control to ensure their sanitary, nutritional, and taste qualities, hence, the need of selecting accurate and safe starter cultures. In the present study, 48 lactic acid bacteria (LAB) strains, previously isolated from Algerian fermented wheat lemzeiet, were analyzed for different technological properties. 14 LAB strains, belonging to Pediococcus pentosaceus, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus brevis, and Leuconostoc mesenteroides species, decreased rapidly the pH of the flour extract broth close to 4 or below. 91% of strains showed extracellular protease activity, but only 12% were amylolytics. 18 LAB strains inhibited or postponed the growth of three fungal targets Rhodotorula mucilaginosa UBOCC-A-216004, Penicillium verrucosum UBOCC-A-109221, and Aspergillus flavus UBOCC-A-106028. The strains belonging to Lactobacillus spp., Leuconostoc fallax, L. mesenteroides, and Weissella paramesenteroides were the most antifungal ones. Multiplex PCR for biogenic amines' production did not reveal any of the genes involved in the production of putrescine, histamine, and tyramine for 17 of the 48 strains. The obtained results provided several candidates for use as starter culture in the future production of lemzeiet.


Assuntos
/microbiologia , Microbiologia de Alimentos , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Triticum/microbiologia , Amilases/metabolismo , Antifúngicos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Aminas Biogênicas/biossíntese , DNA Bacteriano/genética , Fermentação , Concentração de Íons de Hidrogênio , Lactobacillales/enzimologia , Lactobacillales/genética , Peptídeo Hidrolases/metabolismo
12.
J Appl Microbiol ; 127(3): 778-793, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31211891

RESUMO

AIMS: Yeast and bacterial communities inhabit a sourdough starter to make artisanal bread. This study shows whether the interactions of micro-organisms derived from Australian sourdough starters provide some of the positive flavour, and aroma properties to bread by using defined sourdough cultures as the sole leaven in bread production. METHODS AND RESULTS: An investigation of Australian sourdough starters found that they contained Saccharomyces cerevisiae and Kazachstania exigua yeasts. When these yeasts were inoculated alone to ferment wheat flour in an extended fermentation, the bread had a heterogeneous crumb structure, a deeper colour and a distinctive chemical aroma profile than those made with commercial baker's yeast. When bread was made combining these yeasts individually and in combinations with lactic acid bacteria also isolated from these sourdough starters, including Lactobacillus plantarum, L. brevis, L. rossiae, L. casei, the bread aroma profiles and crumb structure were more distinctive, with compounds associated with sour aromas produced, and preferred by sensory panels. CONCLUSIONS: The use of defined mixed cultures as the leaven in bread making, by exploiting the microbial diversity of artisanal Australian starters, can produce bread with distinctive and attractive aromas. SIGNIFICANCE AND IMPACT OF THE STUDY: Understanding and identifying the community ecosystems found in sourdough cultures and using them as the sole leaven in bread production provide novel insights into microbial interactions and how they affect food quality by removing the effects of commercial yeast strains.


Assuntos
Pão/microbiologia , Técnicas de Cocultura , Tecnologia de Alimentos , Austrália , Fermentação , Farinha/microbiologia , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Lactobacillus plantarum/isolamento & purificação , Lactobacillus plantarum/metabolismo , Odorantes , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/isolamento & purificação , Saccharomycetales/metabolismo , Fermento Seco
13.
World J Microbiol Biotechnol ; 35(7): 100, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222403

RESUMO

The spontaneously fermented curdled milk product from Burkina Faso, lait caillé is prepared by traditional processing from raw unpasteurised milk. The fermentation lasts 1-3 days. This study aims to identify the predominant microbiota involved in lait caillé fermentation from cow milk. A survey on lait caillé end-products from local markets showed pH ranges of 3.5 to 4.2. Counts of total lactic acid bacteria (LAB) were 7.8 ± 0.06 to 10.0 ± 0.03 log CFU/g and yeast counts were 5.3 ± 0.06 to 8.7 ± 0.01 log CFU/g, together with considerate amounts of Enterobacteriaceae < 3.00 to 8.4 ± 0.14 log CFU/g. Sampling throughout the entire fermentation of lait caillé was performed at a traditional house-hold production site. A drop in pH from 6.7 ± 0.01 at 0 h to 4.3 ± 0.08 in the end-product (59 h) was found. Total LAB counts increased to 8.6 ± 0.02 log CFU/g in the end-product, while yeast and Enterobacteriaceae counts reached 6.4 ± 0.11 and 6.7 ± 0.00 log CFU/g, respectively. LAB and yeasts isolated during the fermentation were clustered by (GTG)5 repetitive-PCR fingerprinting followed by 16S and 26S rRNA gene sequencing, respectively. Microbial successions were observed with Leuconostoc mesenteroides being the predominant LAB followed by Pediococcus pentosaceus and Weissella paramesenteroides at the onset, while Lactococcus lactis and Enterococcus spp. where the predominant LAB after 7 h of fermentation. During the first 18 h Candida parapsilosis was the dominant yeast species, while from 35 h to the end-product, Saccharomyces cerevisiae predominated. The microbial safety risk pointed out in this study, showed the need for implementation of good manufacturing practices including pasteurisation and use of well-defined starter cultures.


Assuntos
Produtos Fermentados do Leite/microbiologia , Microbiota/genética , Burkina Faso , Contagem de Colônia Microbiana , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Enterococcus/genética , Enterococcus/isolamento & purificação , Fermentação , Manipulação de Alimentos , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Lactococcus lactis/genética , Lactococcus lactis/isolamento & purificação , RNA Ribossômico/genética , RNA Ribossômico/isolamento & purificação , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/isolamento & purificação , Análise de Sequência de RNA , Leveduras/genética , Leveduras/isolamento & purificação
14.
Trop Anim Health Prod ; 51(8): 2279-2286, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31154616

RESUMO

The effects of screened lactic acid bacteria strains were evaluated on growth performance, humoral immunity, and IGF-1 gene expression in broiler chickens. The three dietary groups of negative control fed basal diet, the native LAB probiotic group (NP), and PrimaLac commercial LAB probiotic (PC) were studied. The results revealed that NP and PC diets significantly improved feed conversion ratio and increased body weight, as well as relative weight of carcass compared with group fed NC diet (P < 0.05). Lymphocyte level was significantly increased in birds fed NP and PC (P < 0.01), while serum triglycerides and total cholesterol levels were significantly decreased compared with the NC (P < 0.05). Significant increases were observed in antibody titers against Newcastle disease virus of vaccinated birds (P < 0.03), and morphological analysis of ileum revealed significant increases (P < 0.05) in the villus height and villus height/crypt depth in birds fed NP and PC compared with the NC. The dietary significantly increased Lactobacillus spp. (P < 0.05), while Escherichia coli (P < 0.04) populations were significantly decreased, and also, the expression of IGF-1 gene in liver tissue of broilers fed NP and PC was significantly increased compared with the NC (P < 0.05). These results indicated that the identified native LAB strains can be used commercially as a low-cost probiotic in poultry industry of Iran.


Assuntos
Galinhas/microbiologia , Imunidade Humoral , Lactobacillales/isolamento & purificação , Probióticos , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Galinhas/fisiologia , Dieta/veterinária , Suplementos Nutricionais , Fezes/microbiologia , Íleo/microbiologia , Fator de Crescimento Insulin-Like I/metabolismo , Irã (Geográfico) , Lactobacillales/fisiologia , Lactobacillus , Fígado/metabolismo
15.
Int J Food Microbiol ; 304: 39-48, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31154110

RESUMO

A novel and facile method is developed for rapid estimation of lactic acid bacterial concentration in fermented milk. Growth of bacteria in a liquid changes physicochemical property of the medium and its behavior at solid-liquid interface. Wettability determines characteristic of solid-liquid interface. Nano-rod, helical tetragonal and L-shaped morphologies were designed and fabricated. Hydrophobicity and zeta potential were measured for dried surfaces of 5 dairy bacterial strains. Relationship between microbial population and changes in solid-liquid interface was studied by wettability and surface free energy measurements. Due to hydrophobic surface property of conventional dairy strains, they strongly affect solid-liquid and liquid-vapor surface tensions when dispersed in a liquid, which are dependent on the bacterial concentration. Response surface methodology results showed that type and concentration of bacteria, droplet volume and solid-surface morphology affect wettability significantly. Higher hydrophobicity resulted in higher ∆θ (absolute value of the difference between the pure physiological saline and the bacterial suspension contact angles) dependence on the bacterial concentration. Probiotic bacteria concentration in fermented milk was estimated using the proposed method. A direct relationship was obtained between milk contact angle and bacterial concentration. Results show that this physical method can be applied for rapid estimation of bacterial concentration.


Assuntos
Carga Bacteriana/métodos , Produtos Fermentados do Leite/microbiologia , Lactobacillales/isolamento & purificação , Leite/microbiologia , Animais , Reatores Biológicos , Fermentação , Interações Hidrofóbicas e Hidrofílicas , Ácido Láctico/metabolismo , Probióticos/química , Propriedades de Superfície , Molhabilidade
16.
Lett Appl Microbiol ; 69(3): 204-211, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31250457

RESUMO

Despite of the beneficial relevance of several lactic acid bacteria (LAB) in the food industry, micro-organisms belonging to this group can determine spoilage in food products and carry a number of virulence and antibiotic resistance-related genes. This study aimed on the characterization of beneficial and safety aspects of five bacteriocinogenic LAB strains (Lactobacillus curvatus 12-named L. curvatus UFV-NPAC1), L. curvatus 36, Weissela viridescens 23, W. viridescens 31 and Lactococcus garvieae 36) isolated from an artisanal Brazilian calabresa, a traditional meat sausage. Regarding their beneficial aspects, all tested isolates were positive for mub, while EF226-cbp, EF1249-fbp and EF2380-maz were detected in at least one tested strain; none of the isolates presented map, EFTu or prgB. However, evaluated strains presented a variable pattern of virulence-related genes, but none of the strains presented gelE, cylA, efsA, cpd, int-Tn or sprE. Moreover, other virulence-related genes evaluated in this study were detected at different frequencies. L. curvatus 12 was generated positive results for ace, ccf, int, ermC, tetL, aac(6')-Ie-aph(2″)-Ia, aph(2″)-Ib, aph(2″)-Ic, bcrB, vanB and vanC2; L. curvatus 36: hyl, asa1, esp, int, ermC, tetK, aph(3')-IIIa, aph(2'')-Ic and vanC2; L. garvieae 32: asa1, ant(4')-Ia, aph(2'')-Ib, catA, vanA and vanC1; W. viridescens 23: esp, cob, ermB, aph(3')-IIIa, aph(2'')-Ic, vanA, vanB and vanC2; W. viridescens 31: hyl, esp, ermC, aph(3')-IIIa, aph(2'')-Ib, aph(2'')-Ic, catA, vanA and vanB. Despite presenting some beneficial aspects, the presence of virulence and antibiotic resistance genes jeopardize their utilization as starter or biopreservatives cultures in food products. Considering the inhibitory potential of these strains, an alternative would be the use of their bacteriocins as semi-purified or pure technological preparation. SIGNIFICANCE AND IMPACT OF THE STUDY: The food industry has a particular interest in using bacteriocinogenic lactic acid bacteria (LAB) as starter, probiotics and/or biopreservatives in different food products. Characterization of additional beneficial features is important to identify new, multifunctional potential probiotic strains. However, these strains can only be applied in food products only after being properly characterized according their potential negative aspects, such as virulence and antibiotic resistance genes. A wide characterization of beneficial and safety aspects of bacteriocinogenic LAB is determinant to guide the proper utilization of these strains, or their purified bacteriocins, by the food industry.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/biossíntese , Lactobacillales/genética , Fatores de Virulência/genética , Brasil , Resistência Microbiana a Medicamentos/genética , Enterococcus/isolamento & purificação , Microbiologia de Alimentos , Lactobacillales/isolamento & purificação , Lactobacillus/efeitos dos fármacos , Lactococcus/isolamento & purificação , Produtos da Carne/microbiologia , Virulência
17.
Pol J Microbiol ; 68(2): 203-209, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31250590

RESUMO

The composition of vagina lactic acid bacteria (LAB) differs within the different ethnic group. This study is aimed at determining the prevalence of LAB with their antimicrobial properties in Nigerian women's vagina during different stages of the menstrual cycle. Microorganisms were isolated from vaginal swabs of ten Nigerian women during different stages of the menstrual cycle and identified by partial sequencing of the 16S rRNA gene. The antimicrobial properties of the LAB were tested against the multidrug-resistant uropathogens. The prevalence of LAB was higher during ovulation period while during menstruation period, it declined. Twenty-five LAB isolates were identified as three species, namely: Lactobacillus plantarum (15), Lactobacillus fermentum (9), Lactobacillus brevis (1) and one acetic acid bacteria - Acetobacter pasteurianus. The LAB had antimicrobial activities against the three uropathogens with zones of inhibition from 8 to 22 mm. The presence of LAB inhibits the growth of Staphylococcus sp. GF01 also in the co-culture. High LAB counts were found during ovulation period with L. plantarum as a dominant species while during menstruation, there was a decrease in the LAB counts. The isolated LAB has antimicrobial properties against the urogenital pathogens tested thus exhibiting their potential protective role against uropathogens.The composition of vagina lactic acid bacteria (LAB) differs within the different ethnic group. This study is aimed at determining the prevalence of LAB with their antimicrobial properties in Nigerian women's vagina during different stages of the menstrual cycle. Microorganisms were isolated from vaginal swabs of ten Nigerian women during different stages of the menstrual cycle and identified by partial sequencing of the 16S rRNA gene. The antimicrobial properties of the LAB were tested against the multidrug-resistant uropathogens. The prevalence of LAB was higher during ovulation period while during menstruation period, it declined. Twenty-five LAB isolates were identified as three species, namely: Lactobacillus plantarum (15), Lactobacillus fermentum (9), Lactobacillus brevis (1) and one acetic acid bacteria ­ Acetobacter pasteurianus. The LAB had antimicrobial activities against the three uropathogens with zones of inhibition from 8 to 22 mm. The presence of LAB inhibits the growth of Staphylococcus sp. GF01 also in the co-culture. High LAB counts were found during ovulation period with L. plantarum as a dominant species while during menstruation, there was a decrease in the LAB counts. The isolated LAB has antimicrobial properties against the urogenital pathogens tested thus exhibiting their potential protective role against uropathogens.


Assuntos
Antibiose , Lactobacillales/isolamento & purificação , Lactobacillales/fisiologia , Ciclo Menstrual , Vagina/microbiologia , Acetobacter/classificação , Acetobacter/genética , Acetobacter/isolamento & purificação , Acetobacter/fisiologia , Adulto , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Humanos , Lactobacillales/classificação , Lactobacillales/genética , Nigéria , Filogenia , Prevalência , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Staphylococcus/crescimento & desenvolvimento , Adulto Jovem
18.
Benef Microbes ; 10(5): 579-587, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31122043

RESUMO

γ-Aminobutyric acid (GABA), an amino acid not used in protein synthesis, intervenes in several physiological functions and has both diuretic and calming effects in humans. Lactic acid bacteria (LAB) strains that produce GABA could be exploited for the manufacture of health-promoting GABA-enriched dairy products. In this study, 262 LAB strains isolated from traditional dairy products made from raw milk without starter cultures were screened for GABA production in culture media supplemented with 1% monosodium glutamate (MSG) using an enzymatic (GABase) method. About half of the strains (123) were found to be GABA producers. Of these, 24, among which were 16 Lactococcus lactis subsp. lactis and three Streptococcus thermophilus strains, produced >1 mM of GABA (range 1.01-2.81 mM) and were selected for further characterisation. GABA production was confirmed in most strains by culturing in 5 mM MSG followed by HPLC quantification. A majority of the strains were confirmed to be GABA producers by this method, although lower production levels were recorded. Using species-specific primers, the gene encoding glutamate decarboxylase (GAD) was PCR-amplified in all but one of the GABA producers analysed. Amplicons sequences were compared to one another and to those held in databases. Except for one Lactobacillus brevis strain, none of the 24 GABA producers investigated produced toxic biogenic amines, such as tyramine, histamine or cadaverine. They were therefore considered safe. Either alone, in mixtures, or in combination with industrial starter or adjunct cultures, these strains might be useful in the development of health-oriented dairy products.


Assuntos
Produtos Fermentados do Leite/microbiologia , GABAérgicos/metabolismo , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Ácido gama-Aminobutírico/metabolismo , Técnicas Bacteriológicas , Cromatografia Líquida de Alta Pressão , Glutamato Descarboxilase/genética , Lactobacillales/classificação , Lactobacillales/enzimologia , Reação em Cadeia da Polimerase
19.
Int J Mol Sci ; 20(9)2019 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31035460

RESUMO

A total of 85 strains of lactic acid bacteria were isolated from corn silage in this study and analyzed in vitro for their cholesterol removal, NPC1L1 protein down-regulation and bile salt deconjugation ability, respectively. Nineteen strains were selected for further analysis for their probiotic potential. Finally, 3 strains showing better probiotic potential were evaluated for their cholesterol-lowering activity in hamsters. The strains showing the greater cholesterol removal and NPC1L1 protein down-regulation activity had no significant effects on serum and hepatic cholesterol levels in hamsters (p > 0.05). However, Lactobacillus plantarum CAAS 18008 (1 × 109 CFU/d) showing the greater bile salt deconjugation ability significantly reduced serum low-density lipoprotein cholesterol, total cholesterol, and hepatic total cholesterol levels by 28.8%, 21.7%, and 30.9%, respectively (p < 0.05). The cholesterol-lowering mechanism was attributed to its bile salt hydrolase activity, which enhanced daily fecal bile acid excretion levels and thereby accelerated new bile acid synthesis from cholesterol in liver. This study demonstrated that the strains showing greater cholesterol removal and NPC1L1 protein down-regulation activity in vitro hardly reveal cholesterol-lowering activity in vivo, whereas the strains showing greater bile salt deconjugation ability in vitro has large potential to decrease serum cholesterol levels in vivo.


Assuntos
Lactobacillales/isolamento & purificação , Probióticos/isolamento & purificação , Silagem/microbiologia , Zea mays/microbiologia , Animais , Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Colesterol 7-alfa-Hidroxilase , Cricetinae , Fezes/química , Humanos , Lactobacillales/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Proteínas de Membrana/metabolismo , Redes e Vias Metabólicas , Viabilidade Microbiana , Probióticos/metabolismo , Esteroides/química , Esteroides/isolamento & purificação
20.
Int J Food Microbiol ; 301: 61-72, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31100643

RESUMO

Phyllosphere microorganisms are common contaminants of fruit or vegetable containing foods. The aim of this study was to identify and characterize lactic acid bacteria isolated from fruits and vegetables from Reunion Island, regarding possible application in food. Among 77 isolates, a large diversity of species was observed, with isolates belonging to Lactobacillus plantarum (3 isolates), other species of Lactobacillus (3), Lactococcus lactis (13), Leuconostoc pseudomesenteroides (25), Leuconostoc lactis (1), Leuconostoc mesenteroides (7), Leuconostoc citreum (14), Weissella cibaria (4), Weissella confusa (4), other species of Weissella (2) and Fructobacillus tropaeoli (1). Several of these species, although belonging to lactic acid bacteria, are poorly characterized, because of their low occurrence in dairy products. Lactobacillus, Lactococcus, Leuconostoc and Weissella isolates were classified by (GTG)5 fingerprinting in 3, 6, 21 and 10 genetic groups, respectively, suggesting a large intra-species diversity. Several Weissella and Lactobacillus isolates were particularly tolerant to acid and osmotic stress, whereas Lc. pseudomesenteroides 60 was highly tolerant to oxidative stress. Isolates of Weissella 30, 64 and 58, Leuconostoc 60 and 12b, Lactobacillus 75 and Fructobacillus 77 present relevant characteristics for their use as starters or as preservative cultures for fruits and vegetables.


Assuntos
Microbiologia de Alimentos , Frutas/microbiologia , Lactobacillales/genética , Verduras/microbiologia , Fermentação , Lactobacillales/isolamento & purificação , Lactobacillales/fisiologia , RNA Ribossômico 16S/genética , Clima Tropical
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