scholarly journals Production of γ-aminobutyric acid (GABA) by lactic acid bacteria strains isolated from traditional, starter-free dairy products made of raw milk

2019 ◽  
Vol 10 (5) ◽  
pp. 579-587 ◽  
Author(s):  
J.A. Valenzuela ◽  
A.B. Flórez ◽  
L. Vázquez ◽  
O.M. Vasek ◽  
B. Mayo
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Dairy Products ◽  
Culture Media ◽  
Monosodium Glutamate ◽  
Lactobacillus Brevis ◽  
Raw Milk ◽  
Starter Cultures ◽  
Aminobutyric Acid ◽  
Gaba Production

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.

scholarly journals Diversity of lactic acid bacteria isolated from traditional Montenegrin dairy products

Genetika ◽  
2018 ◽  
Vol 50 (2) ◽  
pp. 465-482
Author(s):  
Mirjana Bojanic-Rasovic ◽  
Sigrid Mayrhofer ◽  
Mary Ochome ◽  
Erna Ajanovic ◽  
Marija Zunabovic ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Dairy Products ◽  
Local Population ◽  
Geographical Area ◽  
Streptococcus Thermophilus ◽  
Raw Milk ◽  
Starter Cultures ◽  
Lactobacillus Species ◽  
Production Environment

Traditional production of fermented dairy products in Montenegro is carried out without adding defined starter cultures. This way of production involves lactic acid bacteria (LAB) that are normally present in the raw milk and production environment. This autochthonous ("wild") fermentation microbiota represents a reservoir of unknown strains. In order to study the LAB diversity, 25 indigenous dairy products in Montenegro have been tested. Isolation was performed on microbial media M17 and MRS agar with or without supplementations under aerobic and anaerobic conditions at temperatures of 30?C, 37 ?C and 44?C. Identification of these isolates at species level was done by species-specific PCR and gene regions sequencing of representatives of each RAPD-cluster. RAPD-PCR was used to characterize the isolates at strain level. Nine Lactobacillus species, five Leuconostoc species, four Enterococcus species as well as strains of the species Lactococcus lactis, Pediococcus pentosaceus and Streptococcus thermophilus were detected. It can be concluded that a rich lactic acid bacteria diversity existed in the analyzed Montenegrin dairy products. Further examination of the isolates could lead to the development of autochthonous starter cultures that would contribute to a product that is characteristic for the geographical area and to which the local population is accustomed.

Evaluating the technological properties of lactic acid bacteria in Wagyu cattle milk

2021 ◽  
pp. 1-7
Author(s):  
Harutoshi Tsuda ◽  
Kana Kodama
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Raw Milk ◽  
Starter Cultures ◽  
Technological Properties ◽  
Mature Milk ◽  
16S Rdna Sequence Analysis ◽  
Physiological And Biochemical Characteristics ◽  
Fermented Dairy Products ◽  
Fermented Dairy

Abstract This paper reveals the technological properties of lactic acid bacteria isolated from raw milk (colostrum and mature milk) of Wagyu cattle raised in Okayama Prefecture, Japan. Isolates were identified based on their physiological and biochemical characteristics as well as 16S rDNA sequence analysis. Streptococcus lutetiensis and Lactobacillus plantarum showed high acid and diacetyl-acetoin production in milk after 24 h of incubation at 40 and 30°C, respectively. These strains are thought to have potential for use as starter cultures and adjunct cultures for fermented dairy products.

scholarly journals Screening and enumeration of lactic acid bacteria in milk using three different culture media in Petrifilm™ Aerobic Count plates and conventional pour plate methodology

2007 ◽  
Vol 74 (4) ◽  
pp. 387-391 ◽  
Author(s):  
Maria BT Ortolani ◽  
Gabriela N Viçosa ◽  
Vanerli Beloti ◽  
Luís A Nero
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Culture Media ◽  
Skim Milk ◽  
Raw Milk ◽  
Excellent Correlation ◽  
Anaerobic Conditions ◽  
Milk Samples ◽  
Experimental Inoculation

This study aimed to compare Petrifilm™ Aerobic Count (AC) plates and the conventional pour plate methodology using de Mann-Rogosa-Sharpe (MRS), Kang-Fung (KF) and Kang-Fung-Sol (KFS) culture media for screening and enumeration of lactic acid bacteria (LAB) in milk. Suspensions of 10 LAB species in reconstituted powder skim milk and 30 raw milk samples, without experimental inoculation, were tested. For selective enumeration, all samples were previously diluted in MRS, KF and KFS broths and then plated in Petrifilm™ AC and conventional pour plate methodology, using the same culture media with added agar. All plates were incubated at 37°C for 48 h in anaerobic conditions. Differences in the counts were observed only for raw milk samples using KFS in conventional methodology, when compared with the counts obtained from MRS and KF (P⩽0·05). The results showed excellent correlation indexes between both methodologies using the three culture media for LAB suspensions (r=0·97 for MRS, KF and KFS). For raw milk samples, the correlation indexes were excellent (r=0·97, for MRS) and good (r=0·84 for KF, and r=0·82 for KFS), showing some interference in Petrifilm™ AC when supplements were added, especially lactic acid. These results indicate the possibility of using Petrifilm™ AC plates for enumeration of LAB in milk, even with the use of selective supplements.

scholarly journals GlnR Negatively Regulates Glutamate-Dependent Acid Resistance in Lactobacillus brevis

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Luchan Gong ◽  
Cong Ren ◽  
Yan Xu
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Glutamate Decarboxylase ◽  
Wild Type Strain ◽  
Acid Resistance ◽  
Lactobacillus Brevis ◽  
Deletion Strain ◽  
Content Type ◽  
Gaba Production ◽  
Encoding Gene

ABSTRACT Lactic acid bacteria often encounter a variety of multiple stresses in their natural and industrial fermentation environments. The glutamate decarboxylase (GAD) system is one of the most important acid resistance systems in lactic acid bacteria. In this study, we demonstrated that GlnR, a nitrogen regulator in Gram-positive bacteria, directly modulated γ-aminobutyric acid (GABA) conversion from glutamate and was involved in glutamate-dependent acid resistance in Lactobacillus brevis. The glnR deletion strain (ΔglnR mutant) achieved a titer of 284.7 g/liter GABA, which is 9.8-fold higher than that of the wild-type strain. The cell survival of the glnR deletion strain was significantly higher than that of the wild-type strain under the condition of acid challenge and was positively correlated with initial glutamate concentration and GABA production. Quantitative reverse transcription-PCR assays demonstrated that GlnR inhibited the transcription of the glutamate decarboxylase-encoding gene (gadB), glutamate/GABA antiporter-encoding gene (gadC), glutamine synthetase-encoding gene (glnA), and specific transcriptional regulator-encoding gene (gadR) involved in gadCB operon regulation. Moreover, GABA production and glutamate-dependent acid resistance were absolutely abolished in the gadR glnR deletion strain. Electrophoretic mobility shift and DNase I footprinting assays revealed that GlnR directly bound to the 5′-untranslated regions of the gadR gene and gadCB operon, thus inhibiting their transcription. These results revealed a novel regulatory mechanism of GlnR on glutamate-dependent acid resistance in Lactobacillus. IMPORTANCE Free-living lactic acid bacteria often encounter acid stresses because of their organic acid-producing features. Several acid resistance mechanisms, such as the glutamate decarboxylase system, F1Fo-ATPase proton pump, and alkali production, are usually employed to relieve growth inhibition caused by acids. The glutamate decarboxylase system is vital for GAD-containing lactic acid bacteria to protect cells from DNA damage, enzyme inactivation, and product yield loss in acidic habitats. In this study, we found that a MerR-type regulator, GlnR, was involved in glutamate-dependent acid resistance by directly regulating the transcription of the gadR gene and gadCB operon, resulting in an inhibition of GABA conversion from glutamate in L. brevis. This study represents a novel mechanism for GlnR's regulation of glutamate-dependent acid resistance and also provides a simple and novel strategy to engineer Lactobacillus strains to elevate their acid resistance as well as GABA conversion from glutamate.

scholarly journals Cultivation media for lactic acid bacteria used in dairy products

2019 ◽  
Vol 86 (4) ◽  
pp. 490-502 ◽  
Author(s):  
Saeed A. Hayek ◽  
Rabin Gyawali ◽  
Sulaiman O. Aljaloud ◽  
Albert Krastanov ◽  
Salam A. Ibrahim
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Growth ◽  
Dairy Products ◽  
Microbial Control ◽  
Starter Cultures ◽  
Isolation And Identification ◽  
Defined Media ◽  
Growth Requirements ◽  
Large Numbers

AbstractThis review aims to familiarize the reader with research efforts on the cultivation media of lactic acid bacteria (LAB). We have also included a brief discussion on standard ingredients used in LAB media and chemically defined media as related to bacterial growth requirements. Recent research has focused on modifying standard media for the enumeration, differentiation, isolation, and identification of starter cultures and probiotics. Even though large numbers of these media have been developed to serve dairy microbial control, they have failed to provide consistent results. The research consequently points to the need to develop a reliable lactobacilli growth medium for the dairy industry.

scholarly journals Synthesis of γ-Aminobutyric Acid by Lactic Acid Bacteria Isolated from a Variety of Italian Cheeses

2007 ◽  
Vol 73 (22) ◽  
pp. 7283-7290 ◽  
Author(s):  
S. Siragusa ◽  
M. De Angelis ◽  
R. Di Cagno ◽  
C. G. Rizzello ◽  
R. Coda ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Brevis ◽  
Amino Acid Sequences ◽  
Lactobacillus Delbrueckii ◽  
Aminobutyric Acid ◽  
Nucleotide Sequence Analysis ◽  
Rrna Gene ◽  
Gaba A ◽  
Health Promoting

ABSTRACT The concentrations of γ-aminobutyric acid (GABA) in 22 Italian cheese varieties that differ in several technological traits markedly varied from 0.26 to 391 mg kg−1. Presumptive lactic acid bacteria were isolated from each cheese variety (total of 440 isolates) and screened for the capacity to synthesize GABA. Only 61 isolates showed this activity and were identified by partial sequencing of the 16S rRNA gene. Twelve species were found. Lactobacillus paracasei PF6, Lactobacillus delbrueckii subsp. bulgaricus PR1, Lactococcus lactis PU1, Lactobacillus plantarum C48, and Lactobacillus brevis PM17 were the best GABA-producing strains during fermentation of reconstituted skimmed milk. Except for L. plantarum C48, all these strains were isolated from cheeses with the highest concentrations of GABA. A core fragment of glutamate decarboxylase (GAD) DNA was isolated from L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48 by using primers based on two highly conserved regions of GAD. A PCR product of ca. 540 bp was found for all the strains. The amino acid sequences deduced from nucleotide sequence analysis showed 98, 99, 90, and 85% identity to GadB of L. plantarum WCFS1 for L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48, respectively. Except for L. lactis PU1, the three lactobacillus strains survived and synthesized GABA under simulated gastrointestinal conditions. The findings of this study provide a potential basis for exploiting selected cheese-related lactobacilli to develop health-promoting dairy products enriched in GABA.

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 Typical Moroccan goat Lactic Acid Bacteria and their assay as starters

2021 ◽  
Author(s):  
Linda Zaaraoui ◽  
Abdellah Bouksaim ◽  
Maha Elhamdani ◽  
Aouatif Benali ◽  
Mohammed Oukassou ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Research Study ◽  
Goat Milk ◽  
Lactobacillus Brevis ◽  
Raw Milk ◽  
Isolation And Identification ◽  
Lactobacillus Pentosus ◽  
Factors Affecting ◽  
Main Factors

The knowledge of lactic acid bacteria of raw milk and the main factors affecting their variability are particularly important issues for the control of cheese processing and the bioconservation of farm raw milk food products. The present research study concerned the isolation and identification of twenty strains of the Lactobacillus genus from goat milk originating from the Oulmes region, using the API 50 CH system. All isolates found represented five species: Lactobacillus plantarum (43.75 %), Lactobacillus brevis (37.75 %), Lactobacillus pentosus (6.25 %), Lactobacillus salivarus (6.25 %), and Lactobacillus acidophilus (6.25 %). According to biochemical activities, the majority of the strains displayed weak acidification and autolysis activities in milk. In contrast, they showed high extracellular proteolytic activity. All isolates produced exopolysaccharides and most of them could metabolize citrate. The absence of hemolytic activity may suggest the use of these isolates as adjunct starters in the food fermentation process.

scholarly journals Tolerance of autochthonous lactic acid bacteria to different processing conditions in vitro

2020 ◽  
Vol 47 (2) ◽  
pp. 119-129
Author(s):  
Mirjana Grujović ◽  
Katarina Mladenović ◽  
Ljiljana Čomić
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Dairy Products ◽  
Starter Cultures ◽  
Processing Conditions ◽  
Dairy Processing ◽  
Nacl Concentration ◽  
Different Temperatures

In this paper, the effect of different temperatures, pH, and NaCl concentration on the growth of autochthonous lactic acid bacteria isolated from traditionally made Serbian cheese (Sokobanja area) was investigated by using the spectrophotometric method. Growth of tested Lactobacillus (Lb. fermentum, Lb. plantarum, and Lb. brevis) and Lactococcus lactis subsp. lactis biovar. diacetylactis five isolates were better in acidic pH, while the growth of Enterococcus isolates (E. durans, E. faecium, and E. faecalis) was better in basic pH, at 37 °C. At 4 °C after 24 h, none of the tested bacteria showed growth. Since the autochthonous isolates were tolerant to a tested range of dairy processing conditions, further studies need to include the characterization of enzymatic activity of selected isolates, as well as the ability to use these isolates like starter cultures or food supplements in dairy or non-dairy products.

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