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1.
Artigo em Inglês | MEDLINE | ID: mdl-38578275

RESUMO

As required by Rule 54 of the International Code of Nomenclature of Prokaryotes, the authors propose the replacement specific epithet 'allocomposti' for the illegitimate prokaryotic name Sphingobacterium composti Yoo et al. 2007, the replacement subspecific epithet 'bovistauri' for Mycobacterium chelonae subsp. bovis Kim et al. 2017 and the replacement subspecific epithet 'allosunkii' for Lactobacillus delbrueckii subsp. sunkii Kudo et al. 2012. Meanwhile, new combinations Christiangramia oceanisediminis and Christiangramia crocea are also proposed as replacements for the illegitimate prokaryotic names Gramella oceanisediminis Yang et al. 2023 and Gramella crocea Zhang et al. 2023, respectively.


Assuntos
Lactobacillus delbrueckii , Lactobacillus , Mycobacteriaceae , Mycobacterium chelonae , Sphingobacterium , Análise de Sequência de DNA , DNA Bacteriano/genética , Filogenia , Técnicas de Tipagem Bacteriana , RNA Ribossômico 16S/genética , Composição de Bases , Ácidos Graxos/química
2.
Molecules ; 29(6)2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38542894

RESUMO

The lactic acid bacteria Streptococcus thermophilus and Lactobacillus helveticus are commonly used as starter cultures in dairy product production. This study aimed to investigate the characteristics of fermented milk using different ratios of these strains and analyze the changes in volatile compounds during fermentation and storage. A 10:1 ratio of Streptococcus thermophilus CICC 6063 to Lactobacillus helveticus CICC 6064 showed optimal fermentation time (4.2 h), viable cell count (9.64 log10 colony-forming units/mL), and sensory evaluation score (79.1 points). In total, 56 volatile compounds were identified and quantified by solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS), including aldehydes, ketones, acids, alcohols, esters, and others. Among these, according to VIP analysis, 2,3-butanedione, acetoin, 2,3-pentanedione, hexanoic acid, acetic acid, acetaldehyde, and butanoic acid were identified as discriminatory volatile metabolites for distinguishing between different time points. Throughout the fermentation and storage process, the levels of 2,3-pentanedione and acetoin exhibited synergistic dynamics. These findings enhance our understanding of the chemical and molecular characteristics of milk fermented with Streptococcus thermophilus and Lactobacillus helveticus, providing a basis for improving the flavor and odor of dairy products during fermentation and storage.


Assuntos
Lactobacillus delbrueckii , Lactobacillus helveticus , Pentanonas , Animais , Leite/química , Streptococcus thermophilus/metabolismo , Fermentação , Acetoína/análise , Lactobacillus delbrueckii/metabolismo , Cetonas/análise
3.
Cell Biochem Funct ; 42(2): e3981, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38509733

RESUMO

Systemic lupus erythematosus (SLE) is known as an autoimmune disorder that is characterized by the breakdown of self-tolerance, resulting in disease onset and progression. Macrophages have been implicated as a factor in the development of SLE through faulty phagocytosis of dead cells or an imbalanced M1/M2 ratio. The study aimed to investigate the immunomodulatory effects of Lactobacillus delbrueckii and Lactobacillus rhamnosus on M1 and M2 macrophages in new case lupus patients. For this purpose, blood monocytes were collected from lupus patients and healthy people and were cultured for 5 days to produce macrophages. For 48 h, the macrophages were then cocultured with either probiotics or lipopolysaccharides (LPS). Flow cytometry and real-time polymerase chain reaction were then used to analyze the expression of cluster of differentiation (CD) 14, CD80, and human leukocyte antigen - DR (HLADR) markers, as well as cytokine expression (interleukin [IL]1-ß, IL-12, tumor necrosis factor α [TNF-α], IL-10, and transforming growth factor beta [TGF-ß]). The results indicated three distinct macrophage populations, M0, M1, and M2. In both control and patient-derived macrophage-derived monocytes (MDMs), the probiotic groups showed a decrease in CD14, CD80, and HLADR expression compared to the LPS group. This decrease was particularly evident in M0 and M2 macrophages from lupus patients and M1 macrophages from healthy subjects. In addition, the probiotic groups showed increased levels of IL-10 and TGF-ß and decreased levels of IL-12, IL1-ß, and TNF-α in MDMs from both healthy and lupus subjects compared to the LPS groups. Although there was a higher expression of pro-inflammatory cytokines in lupus patients, there was a higher expression of anti-inflammatory cytokines in healthy subjects. In general, L. delbrueckii and L. rhamnosus could induce anti-inflammatory effects on MDMs from both healthy and lupus subjects.


Assuntos
Lacticaseibacillus rhamnosus , Lactobacillus delbrueckii , Lúpus Eritematoso Sistêmico , Probióticos , Humanos , Monócitos/metabolismo , Monócitos/patologia , Interleucina-10 , Lactobacillus delbrueckii/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Citocinas/metabolismo , Anti-Inflamatórios/farmacologia , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Interleucina-12/metabolismo , Interleucina-12/farmacologia , Interleucina-12/uso terapêutico , Fator de Crescimento Transformador beta/metabolismo , Probióticos/farmacologia
4.
Appl Environ Microbiol ; 90(3): e0193623, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38376234

RESUMO

In the context of sustainable diet, the development of soy-based yogurt fermented with lactic acid bacteria is an attractive alternative to dairy yogurts. To decipher the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during soy juice (SJ) fermentation, the whole genome of the strain CIRM-BIA865 (Ld865) was sequenced and annotated. Then Ld865 was used to ferment SJ. Samples were analyzed throughout fermentation for their cell number, carbohydrate, organic acid, free amino acid, and volatile compound contents. Despite acidification, the number of Ld865 cells did not rise, and microscopic observations revealed the elongation of cells from 3.6 µm (inoculation) to 36.9 µm (end of fermentation). This elongation was observed in SJ but not in laboratory-rich medium MRS. Using transcriptomic analysis, we showed that the biosynthesis genes of peptidoglycan and membrane lipids were stably expressed, in line with the cell elongation observed, whereas no genes implicated in cell division were upregulated. Among the main sugars available in SJ (sucrose, raffinose, and stachyose), Ld865 only used sucrose. The transcriptomic analysis showed that Ld865 implemented the two transport systems that it contains to import sucrose: a PTS system and an ABC transporter. To fulfill its nitrogen needs, Ld865 probably first consumed the free amino acids of the SJ and then implemented different oligopeptide transporters and proteolytic/peptidase enzymes. In conclusion, this study showed that Ld865 enables fast acidification of SJ, despite the absence of cell division, leads to a product rich in free amino acids, and also leads to the production of aromatic compounds of interest. IMPORTANCE: To reduce the environmental and health concerns related to food, an alternative diet is recommended, containing 50% of plant-based proteins. Soy juice, which is protein rich, is a relevant alternative to animal milk, for the production of yogurt-like products. However, soy "beany" and "green" off-flavors limit the consumption of such products. The lactic acid bacteria (LAB) used for fermentation can help to improve the organoleptic properties of soy products. But metabolic data concerning LAB adapted to soy juice are lacking. The aim of this study was, thus, to decipher the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during fermentation of a soy juice, based on a multidisciplinary approach. This result will contribute to give tracks for a relevant selection of starter. Indeed, the improvement of the organoleptic properties of these types of products could help to promote plant-based proteins in our diet.


Assuntos
Lactobacillales , Lactobacillus delbrueckii , Animais , Fermentação , Lactobacillus/metabolismo , Lactobacillales/metabolismo , Aminoácidos/metabolismo , Sacarose/metabolismo , Lactobacillus delbrueckii/genética , Iogurte/microbiologia
5.
Food Funct ; 15(5): 2655-2667, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38362628

RESUMO

Peptides in milk fermented with Lactobacillus delbrueckii QS306 before and after ultrahigh pressure treatment were identified using proteomics. Subsequently, 16 stable tripeptides were screened out based on activity score prediction, PeptideCutter analysis, and hydrophobicity calculations. Among them, WRP, WSR, and YRP showed the best angiotensin-converting enzyme (ACE) inhibitory activity, and their semi-inhibitory concentrations were 46.707, 300.121, and 89.555 µM, respectively. WRP and WSR were competitive inhibitors, whereas YRP was non-competitive. Gastrointestinal simulation revealed that WRP and YRP had better gastrointestinal stability. The values of RMSD, ΔGbind, ΔGpol, and RSMF obtained from molecular dynamics simulation indicated that the interaction of WRP and ACE was stable. Thus, Lactobacillus delbrueckii QS306-fermented milk can serve as an important source of ACE inhibitory peptides both before and after ultrahigh pressure treatment. The strategy of in silico screening, activity evaluation, and molecular dynamics simulation adopted in this study can be applied to the large-scale screening of novel peptides with high ACE inhibitory activity.


Assuntos
Lactobacillus delbrueckii , Lactobacillus , Leite , Animais , Leite/química , Lactobacillus delbrueckii/metabolismo , Inibidores da Enzima Conversora de Angiotensina/química , Simulação de Dinâmica Molecular , Peptídeos/química , Peptidil Dipeptidase A/metabolismo , Simulação de Acoplamento Molecular
6.
Int J Biol Macromol ; 259(Pt 2): 129112, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38176482

RESUMO

This study assessed the potential prebiotic characteristics of the previously reported Lactiplantibacillus plantarum extracellular polysaccharide (EPS-T1) with immunological activity. EPS-T1 was a novel heteropolysaccharide composed of glucose and galactose (1.00:1.21), with a molecular weight of 1.41 × 106 Da. The monosaccharide composition, molecular weight, fourier transform infrared, and 1H NMR analysis showed that EPS-T1 was well tolerated in the simulated oral cavity, gastric fluid, and small intestinal fluid environments, and was not easily degraded. Meanwhile, EPS-T1 could effectively be used as a carbon source to promote the growth of beneficial Lactobacillus species (Lactobacillus delbrueckii ssp. Bulgaricus, Streptococcus thermophilus, Lacticaseibacillus rhamnose GG, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei and Lactobacillus reuteri). After 24 h of fecal fermentation, EPS-T1(5 mg/mL) effectively reduced the relative abundance of harmful bacteria such as the Escherichia-Shigella, Citrobacter, Fusobacterium, Parasutterella, and Lachnoclostridium. While, the level content of beneficial flora (Bacteroides, Blautia, Phascolarctobacterium, Bifidobacterium, Parabacteroides, and Subdoligranulum) were significantly increased. In addition, EPS-T1 was able to significantly promote the enrichment of short-chain fatty acids such as acetic acid, propionic acid and butyric acid. These results provide some basis for the functional application of EPS-T1 as a potential prebiotic.


Assuntos
Microbioma Gastrointestinal , Lactobacillus delbrueckii , Lactobacillus plantarum , Polissacarídeos Bacterianos/química , Digestão , Prebióticos , Lactobacillus/metabolismo , Lactobacillus plantarum/metabolismo , Fermentação
7.
Int J Biol Macromol ; 260(Pt 1): 129468, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38242412

RESUMO

This study investigated the possibility of sodium carboxymethyl celluloses (Na-CMC) in protecting the viability of lactic acid bacteria (LAB) against freeze-drying stress. 1 % concentration of Na-CMC with a 0.7 substitution degree and viscosity of 1500 to 3100 (MPa.s) was found to protect Lactobacillus delbrueckii subsp. bulgaricus CICC 6098 best, giving a high survival rate of 23.19 ± 0.88 %, high key enzymatic activities, and 28-day storage stability. Additionally, Na-CMC as cryoprotectant provided good protection for other 7 lactic acid bacterial strains subjected to freeze-drying. The highest survival rate was 48.79 ± 0.20 U/mg for ß-GAL, 2.75 ± 0.15 U/mg for Na+-K+-ATPase, and 2.73 ± 0.41 U/mg for Ca2+-Mg2+-ATPase as 48.48 ± 0.46 % for freeze-dried Pediococcus pentosaceus CICC 22228. It was Interesting to note that the presence of Na-CMC reduced the freezable water content of the lyophilized powders containing the tested strains through its hydroxyl group, and supplied micro-holes and fibers for protecting the integrated structure of LAB cell membrane and wall against the freezing damage. It is clear that addition of Na-CMC should be promising as a new cryoprotective agent available for processing the lyophilized stater cultures of LAB strains.


Assuntos
Lactobacillales , Lactobacillus delbrueckii , Crioprotetores/farmacologia , Crioprotetores/química , Carboximetilcelulose Sódica , Liofilização , Ácido Láctico , Sódio , Adenosina Trifosfatases
8.
J Dairy Sci ; 107(1): 123-140, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37641256

RESUMO

This study aimed to investigate the symbiosis between Streptococcus thermophilus CICC 6038 and Lactobacillus delbrueckii ssp. bulgaricus CICC 6047. In addition, the effect of their different inoculum ratios was determined, and comparison experiments of fermentation characteristics and storage stability of milk fermented by their monocultures and cocultures at optimal inoculum ratio were performed. We found the time to obtain pH 4.6 and ΔpH during storage varied among 6 inoculum ratios (1:1, 2:1, 10:1, 19:1, 50:1, 100:1). By the statistical model to evaluate the optimal ratio, the ratio of 19:1 was selected, which exhibited high acidification rate and low postacidification with pH values remaining between 4.2 and 4.4 after a 50-d storage. Among the 3 groups included in our analyses (i.e., the monocultures of S. thermophilus CICC 6038 [St] and Lb. bulgaricus CICC 6047 [Lb] and their cocultures [St+Lb] at 19:1), the coculture group showed higher acidification activity, improved rheological properties, richer typical volatile compounds, more desirable sensor quality after the fermentation process than the other 2 groups. However, the continuous accumulation of acetic acid during storage showed that acetic acid was more highly correlated with postacidification than d-lactic acid for the Lb group and St+Lb group. Our study emphasized the importance of selecting an appropriate bacterial consortium at the optimal inoculum ratio to achieve favorable fermentation performance and enhanced postacidification stability during storage.


Assuntos
Lactobacillus delbrueckii , Iogurte , Animais , Iogurte/microbiologia , Streptococcus thermophilus , Fermentação , Acetatos
9.
Tissue Barriers ; 12(1): 2184157, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-36852963

RESUMO

Lactic acid bacteria (LAB) are commonly used probiotics that improve human health in various aspects. We previously reported that yogurt starter strains, Lactobacillus delbrueckii subsp. bulgaricus 2038 and Streptococcus thermophilus 1131, potentially enhance the intestinal epithelial barrier function by inducing the expression of antimicrobial peptides in the small intestine. However, their effects on physical barrier functions remain unknown. In this study, we found that both strains ameliorated the decreased trans-epithelial resistance and the increased permeability of fluorescein isothiocyanate-dextran induced by tumor necrosis factor (TNF)-α and interferon (IFN)-γ in Caco-2 cells. We also demonstrated that LAB prevented a decrease in the expression and disassembly of tight junctions (TJs) induced by TNF-α and IFN-γ. To assess the repair activity of TJs, a calcium switch assay was performed. Both strains were found to promote the reassembly of TJs, and their activity was canceled by the inhibitor of AMP-activated protein kinase (AMPK). Moreover, these strains showed increased AMPK phosphorylation. These observations suggest that the strains ameliorated physical barrier dysfunction via the activation of AMPK. The activities preventing barrier destruction induced by TNF-α and IFN-γ were strain-dependent. Several strains containing L. bulgaricus 2038 and S. thermophilus 1131 significantly suppressed the barrier impairment, and L. bulgaricus 2038 showed the strongest activity among them. Our findings suggest that the intake of L. bulgaricus 2038 and S. thermophilus 1131 is a potential strategy for the prevention and repair of leaky gut.


Assuntos
Proteínas Quinases Ativadas por AMP , Lactobacillus delbrueckii , Humanos , Proteínas Quinases Ativadas por AMP/metabolismo , Células CACO-2 , Iogurte/microbiologia , Fator de Necrose Tumoral alfa/metabolismo , Lactobacillus delbrueckii/metabolismo
10.
Int J Food Microbiol ; 411: 110523, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38134579

RESUMO

Traditional products are particularly appreciated by consumers and among these products, cheese is a major contributor to the Italian mountainous area economics. In this study, shotgun metagenomics and volatilomics were used to understand the biotic and abiotic factors contributing to mountain Caciotta cheese typicity and diversity. Results showed that the origin of cheese played a significant role; however, curd cooking temperature, pH, salt concentration and water activity also had an impact. Viral communities exhibited higher biodiversity and discriminated cheese origins in terms of production farms. Among the most dominant bacteria, Streptococcus thermophilus showed higher intraspecific diversity and closer relationship to production farm when compared to Lactobacillus delbrueckii. However, despite a few cases in which the starter culture was phylogenetically separated from the most dominant strains sequenced in the cheese, starter cultures and dominant cheese strains clustered together suggesting substantial starter colonization in mountain Caciotta cheese. The Caciotta cheese volatilome contained prominent levels of alcohols and ketones, accompanied by lower proportions of terpenes. Volatile profile not only demonstrated a noticeable association with production farm but also significant differences in the relative abundances of enzymes connected to flavor development. Moreover, correlations of different non-homologous isofunctional enzymes highlighted specific contributions to the typical flavor of mountain Caciotta cheese. Overall, this study provides a deeper understanding of the factors shaping typical mountain Caciotta cheese, and the potential of metagenomics for characterizing and potentially authenticating food products.


Assuntos
Queijo , Lactobacillus delbrueckii , Animais , Queijo/microbiologia , Bactérias , Temperatura , Itália , Leite/microbiologia
11.
Ultrason Sonochem ; 102: 106726, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38113583

RESUMO

In this study, the effects of ultrasonicated Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactiplantibacillus plantarum AF1 (100 W, 30 kHz, 3 min) on the safety and bioactive properties of stirred yoghurt during storage (4 °C for 21 days) were investigated. The results showed that sonicated cultures were more effective in reducing pathogens than untreated ones. The highest antioxidant activity (DPPH and ABTS), α-glucosidase and α-amylase inhibition capacity were found in yoghurt containing sonicated probiotic + sonicated yoghurt starter cultures (P + Y + ). The highest amount of peptides (12.4 mg/g) was found in P + Y + yoghurts at the end of the storage time. There were not significant differences between the exopolysaccharide content of P + Y+ (17.30 mg/L) and P + Y- (17.20 mg/L) yoghurts, although it was significantly (P ≤ 0.05) higher than the other samples. The use of ultrasonicated cultures could enhance the safety of stirred yoghurt and improve its functional and bioactive properties.


Assuntos
Lactobacillus delbrueckii , Lactobacillus plantarum , Lactobacillus delbrueckii/fisiologia , Streptococcus thermophilus , Iogurte , Fermentação
12.
Sci Bull (Beijing) ; 68(20): 2405-2417, 2023 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-37718237

RESUMO

Traditional fermented milks are produced by inoculating technique, which selects well-adapted microorganisms that have been passed on through generations. Few reports have used naturally fermented milks as model ecosystems to investigate the mechanism of formation of intra-species microbial diversity. Here, we isolated and whole-genome-sequenced a total of 717 lactic acid bacterial isolates obtained from 12 independent naturally fermented milks collect from 12 regions across five countries. We further analyzed the within-sample intra-species phylogenies of 214 Lactobacillus helveticus isolates, 97 Lactococcus lactis subsp. lactis isolates, and 325 Lactobacillus delbrueckii subsp. bulgaricus isolates. We observed a high degree of intra-species genomic and functional gene diversity within-/between-sample(s). Single nucleotide polymorphism-based phylogenetic reconstruction revealed great within-sample intra-species heterogeneity, evolving from multiple lineages. Further phylogenetic reconstruction (presence-absence gene profile) revealed within-sample inter-clade functional diversity (based on carbohydrate-active enzyme- and peptidase-encoding genes) in all three investigated species/subspecies. By identifying and mapping clade-specific genes of intra-sample clades of the three species/subspecies to the respective fermented milk metagenome, we found extensive potential inter-/intra-species horizontal gene transfer events. Finally, the microbial composition of the samples is closely linked to the nucleotide diversity of the respective species/subspecies. Overall, our results contribute to the conservation of lactic acid bacteria resources, providing ecological insights into the microbial ecosystem of naturally fermented dairy products.


Assuntos
Lactobacillales , Lactobacillus delbrueckii , Lactococcus lactis , Animais , Leite/microbiologia , Lactobacillales/genética , Lactobacillus/genética , Ecossistema , Filogenia , Lactobacillus delbrueckii/genética
13.
J Biotechnol ; 374: 90-100, 2023 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-37572793

RESUMO

The fermentation process of milk to yoghurt using Lactobacillus delbrueckii subsp. bulgaricus in co-culture with Streptococcus thermophilus is hallmarked by the breakdown of lactose to organic acids such as lactate. This leads to a substantial decrease in pH - both in the medium, as well as cytosolic. The latter impairs metabolic activities due to the pH-dependence of enzymes, which compromises microbial growth. To quantitatively elucidate the impact of the acidification on metabolism of L. bulgaricus in an integrated way, we have developed a proton-dependent computational model of lactose metabolism and casein degradation based on experimental data. The model accounts for the influence of pH on enzyme activities as well as cellular growth and proliferation of the bacterial population. We used a machine learning approach to quantify the cell volume throughout fermentation. Simulation results show a decrease in metabolic flux with acidification of the cytosol. Additionally, the validated model predicts a similar metabolic behaviour within a wide range of non-limiting substrate concentrations. This computational model provides a deeper understanding of the intricate relationships between metabolic activity and acidification and paves the way for further optimization of yoghurt production under industrial settings.


Assuntos
Lactobacillus delbrueckii , Lactobacillus delbrueckii/metabolismo , Lactose , Metabolismo dos Carboidratos , Fermentação , Concentração de Íons de Hidrogênio
14.
Molecules ; 28(13)2023 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-37446903

RESUMO

Yak yogurt, which is rich in microorganisms, is a naturally fermented dairy product prepared with ancient and modern techniques by Chinese herdsmen in the Qinghai-Tibet Plateau. The objective of this research was to assess the impact of Lactobacillus bulgaricus and Streptococcus thermophilus starter cultures on the quality and shelf life of yak yogurt, as well as the genetic stability across multiple generations, in comparison to commercially available plain yogurt and peach oat flavor yogurt. Following that, the samples were evenly divided into four treatment groups denoted as T1 (treatment 1), T2, T3, and T4, with each group employing a distinct source of yogurt formulation. T1 included L. bulgaricus, T2 comprised S. thermophilus, T3 consisted of plain yogurt, and T4 represented peach oat yogurt flavor. The findings indicate that T1 yogurt consistently presents a lower pH and higher acidity compared to the other three yogurt types throughout the entire generation process. Moreover, the fat content in all generations of the four yogurt types exceeds the national standard of 3.1 g/100 g, while the total solid content shows a tendency to stabilize across generations. The protein content varies significantly among each generation, with T1 and T4 yogurt indicating higher levels compared to the T2 and T3 yogurt groups. In terms of overall quality, T1 and T4 yogurt are superior to T2 and T3 yogurt, with T1 yogurt being the highest in quality among all groups. The findings revealed that the inclusion of L. bulgaricus led to enhanced flavor, texture, and genetic stability in yak yogurt. This study will serve as a valuable source of data, support, and methodology for the development and screening of compound starters to be utilized in milk fermentation in future research and applications.


Assuntos
Lactobacillus delbrueckii , Iogurte , Animais , Bovinos , Iogurte/análise , Leite/química , Tibet , Lactobacillus delbrueckii/metabolismo , Streptococcus thermophilus/metabolismo , Fermentação
15.
Sci Rep ; 13(1): 11215, 2023 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-37433826

RESUMO

This research aimed to investigate the properties of bio rayeb milk that results from goats fed on feed supplemented with different concentrations of coriander oil. The study design included a control treatment (C) and two coriander oil concentrations, a low level of (0.95%) T1 and a high level of (1.9%) T2. A probiotic starter culture, Direct Vat Set (DVS) of lactobacillus delbrueckii ssp. bulgaricus and streptococcus salivarius ssp. thermophilus in the ratio (1:1) was used to prepare bio rayeb. All treatments were stored at 4 °C for 2 weeks and analyzed on day one and at the end of storage. Results showed that the coagulation time during bio rayeb manufacturing remained consistent at almost 6 h for all batches. However, using a high coriander oil level (1.90%) significantly decreased the apparent viscosity and the content of monounsaturated fatty acids. The DPPH inhibition and the content of monounsaturated fatty acids increased. The electrophoresis chromatogram exhibited a high degree of proteolysis in T2 compared to the control and T1. Microbiologically, yeast, molds, and coliforms were absent in all treatments. Feeding goats on provender supplemented with a low concentration of coriander oil may positively impact the resultant milk's technological and sensorial properties.


Assuntos
Lactobacillus delbrueckii , Óleos Voláteis , Animais , Leite , Cabras , Saccharomyces cerevisiae , Ácidos Graxos Monoinsaturados , Streptococcus thermophilus
16.
Int J Mol Sci ; 24(14)2023 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-37511069

RESUMO

Lactobacillus delbrueckii, the type species of the genus Lactobacillus, is widely recognized as the primary starter culture in the dairy industry due to its proteolytic activity, which enables it to growth in milk. In this study, a comprehensive genomic analysis of the proteolytic system was conducted on L. delbrueckii strains. The analysis included 27 genomes of L. delbrueckii, with a specific focus on the key enzyme involved in this system, the cell envelope-associated proteinase (CEP). The amino acid sequences, as well as the protein-structure prediction of the CEPs, were compared. Additionally, syntenic analysis of the genomic locus related to the CEPs revealed high conservation in L. delbrueckii subsp. bulgaricus strains, while L. delbrueckii subsp. lactis strains exhibited greater variability, including the presence of insertion sequences, deletions, and rearrangements. Finally, the CEP promoter region and putative regulatory elements responsible for controlling the expression of the proteolytic system in lactobacilli were investigated. Our genomic analysis and in silico characterization of the CEPs contribute to our understanding of proteolytic activity and the potential applications of these lactic acid bacteria in the dairy industry. Further research in this area will expand our knowledge and potential practical uses of these findings.


Assuntos
Lactobacillus delbrueckii , Lactobacillus delbrueckii/genética , Peptídeo Hidrolases/metabolismo , Lactobacillus , Sequência de Aminoácidos , Genômica
17.
J Sci Food Agric ; 103(15): 7374-7380, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37427487

RESUMO

BACKGROUND: Lactose maldigestion or intolerance affects a large number of individuals worldwide. If lactose is hydrolyzed by the ß-galactosidase enzyme during the fermentation process, lactose-intolerant individuals can consume milk products without experiencing diarrhea, flatulence, or other symptoms. RESULTS AND CONCLUSION: We isolated and characterized Streptococcus thermophilus, which exhibits high ß-galactosidase activity. This was then used as a starter culture with Lactobacillus delbrueckii subsp. bulgaricus in yogurt to determine the effects of different starter ratios and fermentation temperatures on its organoleptic and physical properties. The ß-galactosidase activity of the isolated strain was 2.60 units mg-1 . The optimal temperature was 42 °C for St. thermophilus to acidify yogurt faster than at other temperatures and it was effective in hydrolyzing the lactose in the media and yogurt. The lactic acid bacteria (LAB) population in 37 °C fermented yogurt was higher than in the other samples, but the starters St. thermophilus and Lb. bulgaricus with a ratio of 2:1 used lactose more effectively than other sample ratios. The lactose content decreased significantly at 37 °C, where it was ~50% hydrolyzed. The acceptability of the sensory properties of yogurt was unaffected by relative lower fermentation temperatures (30 and 37 °C), despite using different ratios of St. thermophilus and Lb. bulgaricus as starter cultures. © 2023 Society of Chemical Industry.


Assuntos
Lactobacillus delbrueckii , Lactose , Humanos , Animais , Streptococcus thermophilus , Iogurte , Diarreia , Fermentação , Leite , beta-Galactosidase
18.
Biotechnol Bioeng ; 120(8): 2186-2198, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37428554

RESUMO

Genome-scale metabolic models and flux balance analysis (FBA) have been extensively used for modeling and designing bacterial fermentation. However, FBA-based metabolic models that accurately simulate the dynamics of coculture are still rare, especially for lactic acid bacteria used in yogurt fermentation. To investigate metabolic interactions in yogurt starter culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, this study built a dynamic metagenome-scale metabolic model which integrated constrained proteome allocation. The accuracy of the model was evaluated by comparing predicted bacterial growth, consumption of lactose and production of lactic acid with reference experimental data. The model was then used to predict the impact of different initial bacterial inoculation ratios on acidification. The dynamic simulation demonstrated the mutual dependence of S. thermophilus and L. d. bulgaricus during the yogurt fermentation process. As the first dynamic metabolic model of the yogurt bacterial community, it provided a foundation for the computer-aided process design and control of the production of fermented dairy products.


Assuntos
Lactobacillales , Lactobacillus delbrueckii , Iogurte/microbiologia , Metagenoma , Lactobacillus delbrueckii/genética , Fermentação
19.
J Sci Food Agric ; 103(15): 7494-7505, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37411001

RESUMO

BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) is a pathogen that causes traveler's diarrhea, for which an effective vaccine is lacking. Previous studies showed that Limosilactobacillus reuteri could inhibit E. coli, effectively increase the expression of its tight junction protein, and reduce the adhesion of ETEC to the intestinal epithelial Caco-2 cell line. In this study, three kinds of yogurt with different starter cultures were first prepared: Lm. reuteri yogurt (fermented by Lm. reuteri alone), traditional yogurt (fermented by Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus at a ratio of 1:1) and mixed yogurt (fermented by Lm. reuteri, S. thermophilus and L. delbrueckii subsp. bulgaricus at a ratio of 1:1:1). The physiological properties, oxidative stress, intestinal barrier function, tight junction protein, pathological conditions and intestinal microbiota composition were investigated. RESULTS: The data showed that Lm. reuteri-fermented yogurt pregavage could effectively alleviate the intestinal barrier impairment caused by ETEC in mice. It alleviated intestinal villus shortening and inflammatory cell infiltration, decreased plasma diamine oxidase concentration and increased claudin-1 and occludin expression in the jejunum of ETEC-infected mice. In addition, Lm. reuteri-fermented yogurt significantly reduced the ETEC load in fecal samples, reversed the increase in Pseudomonadota abundance and decreased Bacteroidota abundance caused by ETEC infection. Furthermore, the composition of the intestinal microbiota could maintain a stable state similar to that in healthy mice. CONCLUSION: These findings indicate that Lm. reuteri-fermented yogurt could alleviate intestinal barrier damage, inhibit ETEC growth and maintain the stability of the intestinal microbiota during ETEC infection. © 2023 Society of Chemical Industry.


Assuntos
Escherichia coli Enterotoxigênica , Infecções por Escherichia coli , Lactobacillus delbrueckii , Limosilactobacillus reuteri , Humanos , Animais , Camundongos , Diarreia/prevenção & controle , Iogurte , Células CACO-2 , Viagem , Lactobacillus delbrueckii/metabolismo , Infecções por Escherichia coli/prevenção & controle , Proteínas de Junções Íntimas/metabolismo
20.
Int J Biol Macromol ; 245: 125375, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37321439

RESUMO

We present the structure, biological activity, peptide composition, and emulsifying properties of pea protein isolate (PPI) after hydrolysis by cell envelope proteinase (CEP) from Lactobacillus delbrueckii subsp. bulgaricus. Hydrolysis resulted in the unfolding of the PPI structure, characterized by an increase in fluorescence and UV absorption, which was related to thermal stability as demonstrated by a significant increase in ΔH and the thermal denaturation temperature (from 77.25 ± 0.05 to 84.45 ± 0.04 °C). The hydrophobic amino acid of PPI significantly increased from 218.26 ± 0.04 to 620.77 ± 0.04 followed by 557.18 ± 0.05 mg/100 g, which was related to their emulsifying properties, with the maximum emulsifying activity index (88.62 ± 0.83 m2/g, after 6 h hydrolysis) and emulsifying stability index (130.77 ± 1.12 min, after 2 h hydrolysis). Further, the results of LC-MS/MS analysis demonstrated that the CEP tended to hydrolyze peptides with an N-terminus dominated by Ser and a C-terminus dominated by Leu, which enhanced the biological activity of pea protein hydrolysates, as supported by their relatively high antioxidant (ABTS+ and DPPH radical scavenging rates were 82.31 ± 0.32% and 88.95 ± 0.31%) and ACE inhibitory (83.56 ± 1.70%) activities after 6 h of hydrolysis. 15 peptide sequences (score > 0.5) possessed both antioxidant and ACE inhibitory activity potential according to the BIOPEP database. This study provides theoretical guidance for the development of CEP-hydrolyzed peptides with antioxidant and ACE inhibitory activity that can be used as emulsifiers in functional foods.


Assuntos
Lactobacillus delbrueckii , Peptídeo Hidrolases , Peptídeo Hidrolases/metabolismo , Lactobacillus delbrueckii/metabolismo , Hidrolisados de Proteína/química , Antioxidantes/farmacologia , Cromatografia Líquida , Espectrometria de Massas em Tandem , Peptídeos/química , Endopeptidases
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