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Chickpea is a nutritious staple pulse with numerous consumption patterns. It is also used in bakery products, especially in bread, in the forms of chickpea flour, fermented-chickpea liquor (FCL), and chickpea yeast (FCL-fermented sourdough) in various countries. However, a large variation exists in the traditional fermentation of FCL and chickpea yeast (CY). In this study, fermentation parameters (cracked-chickpea size, water-chickpea ratio, fermentation temperature, and fermentation time) for the production of FCL and CY were sequentially optimized through separate RSM designs. Therefore, this study aimed at optimization of the fermentation conditions for the preparations of both FCL and CY. First, FCL production parameters of fermentation temperature, time, chickpea particle size, and waterchickpea ratio were optimized and determined to be 40°C, 26 h, 2-6 mm, and 4:1 ratio, respectively. Secondly, the CY process parameters (fermentation temperature and time) were optimized using the optimized FCL conditions and determined to be 38°C and 9 h. The validation studies proved that there is no statistical difference (p>0.05) between the RSM-model predicted and experimental responses. At the optimized fermentation conditions, the FCL and CY had pH values of 4.44 and 4.31, and LAB counts of 9.87 and 9.08 log cfu g-1. The optimum fermentation conditions determined in this study are somewhat comparable to those commonly employed in the traditional preparations of both FCL and CY. Such optimization could lead to the better utilization of FCL and CY in the food industry and improved consumer health outcomes. [ABSTRACT FROM AUTHOR]

Background: Establishing novel preharvest intervention strategies for leafy green growers is of critical need with the rise in foodborne outbreaks associated with these products. Recent studies have shown that lactic acid bacteria (LAB) are able to reduce the presence of Escherichia coli O157:H7 in various food matrices. Electrostatic application of organic acids has been shown to be effective as a postharvest safety intervention to reduce E.coli O157:H7 on leafy greens. The effect of LAB electrostatically applied and sprinkler irrigated once over a 4 week growth cycle was evaluated against E. coli O157:H7 on spinach. Results: The results indicated that E. coli O157:H7 when applied once during the 4 week growth cycle will survive in the soil and spinach leaves at harvest. LAB applied electrostatically and by sprinkler irrigation water on the soil and/or leaf surface within the first 4 weeks of the growing cycle resulted in a significant reduction (almost a 3 log10 reduction) of E. coli O157:H7 both on the leaf and in the soil at harvest, regardless of the application time (P < 0.01). Conclusion: LAB surface treatments have the potential to improve the safety of leafy green plants as a preharvest food safety intervention when combined with good agricultural practices. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) are attractive hosts for the expression of heterologous proteins and can be engineered to deliver therapeutic proteins or peptides to mucosal surfaces. The gastric stable pentadecapeptide BPC-157 is able to prevent and treat gastrointestinal inflammation by reducing the production of reactive oxygen species (ROS). In this study, we used LAB Lactococcus lactis as a vector to deliver BPC-157 by surface display and trypsin shedding or by secretion to the growth medium. Surface display of BPC-157 was achieved by fusing it with basic membrane protein A (BmpA) or with the peptidoglycan binding domain of AcmA and Usp45 secretion signal. While the expression of BmpA-fusion proteins was higher than that of AcmA/Usp45-fusion protein, the surface display ability of BPC-157 was approximately 14-fold higher with AcmA/Usp45-fusion protein. Release of BPC-157 from the bacterial surface or from isolated fusion proteins by trypsinization was demonstrated with anti-BPC-157 antibodies or by mass spectrometry. The concentration of BPC-157 delivered by surface display via AcmA/Usp45-fusion was 30 ng/ml. This increased to 117 ng/ml by Usp45 signal-mediated secretion, making the latter the most effective lactococcal delivery approach for BPC-157. Secreted BPC-157 significantly decreased ROS production in 149BR fibroblast cell model, suggesting its potential benefit in the treatment of intestinal inflammations. Additionally, a comparison of different modes of small peptide delivery by L. lactis, performed in the present study, will facilitate the future use of L. lactis as peptide delivery vehicle. [ABSTRACT FROM AUTHOR]

Abstract The objective of the study was to assess the development of the biogenic amine content in model cheese samples individually inoculated with two biogenic amine producing non-starter lactic acid bacteria strains of Lactobacillus curvatus subsp. curvatus (DEPE T3 and DEPE T36) and two biogenic amine producing non-starter lactic acid bacteria strains of Lactobacillus paracasei (DEPE T51 and DEPE T52) over the course of a 90 day storage period (10 ± 1 °C). During the entire ripening period, the dominant biogenic amine was tyramine. After just two months of ripening, tyramine concentration 167 mg/kg was detected in the model cheeses with the DEPE T3 strain (moreover a total biogenic amine concentration was 220 mg/kg), whilst in the case of the DEPE T36 strain it was even 211 mg/kg of tyramine (sum of biogenic amine was 302 mg/kg). In the samples with the added DEPE T51 and DEPE T52 strains, tyramine concentration after 90 days of ripening almost reached the level of 50 mg/kg. Highlights • The ability of NSLAB isolates to produce biogenic amine was observed in cheese. • Strains of Lb. curvatus subsp. curvatus and Lb. paracasei were tested. • Biogenic amine production by Lb. curvatus was significantly higher during ripening. • Tyramine (PubChem CID: 5610) was the most common biogenic amine. [ABSTRACT FROM AUTHOR]

The microbial diversity and pasting properties of three sourdoughs produced from composite gluten-free flours were investigated using 16S rRNA gene clone libraries and the Rapid Viscoanalyser. Finger millet-pearl millet (FP), Pearl millet-sorghum (PS) and Finger millet-sorghum (FS) sourdoughs were produced. Eleven aerobic bacteria and twelve lactic acid bacteria (LAB) were randomly selected from the sourdoughs. Presumptive Bacillus subtilis and Pediococcus spp. were identified in all the sourdoughs after 48 h of fermentation, while yeast was not detected in any of the products. The LAB population and pH ranged from log 7.70 CFU g −1 to log 10.52 CFU g −1 and 3.8 to 4.2 respectively. The findings showed that well-developed sourdough could be produced from these composite flours by spontaneous fermentation. Significant differences were observed in the pasting properties of all the sourdoughs. Decline in the tendency to retrograde occurred in all sourdoughs, thereby justifying the lower staling rate of final products. This study enhanced the corpus of existing knowledge on the microbial diversity of gluten-free sourdough and provided a basis for the possible application of Pediococcus spp. and Weisella spp. as a starter culture(s) in fermented products. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria are fully recognized for their industrial applications among which the production and release of exopolysaccharides. In the present investigation, we screened fifteen Lactobacilli in order to find ropy strains, quantify exopolysaccharides and detect proteins specifically associated with the ropy-exopolysaccharide production. The highest ropy-exopolysaccharide producer ( L. helveticus 6E8), was grown in stimulating and basal condition (10% and 2% lactose) and subjected to comparative proteomic analysis. The levels of 4 proteins were found significantly increased in the membrane fraction under stimulating conditions: a specific exopolysaccharide biosynthetic protein, a stress-induced protein, a protein involved in secretion and an ATP-synthase subunit. Conversely, several enzymes involved in anabolism and protein synthesis were decreased. These results suggest a general shift from growth to exopolysaccharide-mediated protection from the hyperosmotic environment. Due to the great interest in exopolysaccharides with novel features, the identification of these proteins could have implications for future improvements of industrial strains. [ABSTRACT FROM AUTHOR]

The isolation of bacteria from artisanal dairy products has increased in different countries, it has reported special technological properties, responsible for giving to dairy products unique characteristics. The kinetic parameters of native microorganisms are important for biotechnological scaling. This research, to evaluated the kinetics of bacterial growth under optimal conditions of lactic acid bacterial isolated from artisanal fermented milk "Suero Costeño" Lactobacillus plantarum (Lp), Streptococcus infantarius (Si) and Lactococcus lactis (Ll), identified by 16S rRNA. There were fast rate acidification of Si and Ll as a typical dairy starter culture. Lp showed a slowly rate acidification and highest pH resistance. It is necessary a pH control between 5,3 and 5,7 in order to obtain higher consume of substrate and yield biomass. Si and Ll can be used as primary cultures in fermentations as a result of their rapid acidification and Lp as an adjunct culture through the slow acid production. [ABSTRACT FROM AUTHOR]

In this study, a novel sampling method was established to study changes in the activity of lactic acid bacteria during spray drying. Before spray drying, a sampling device with a refrigerant and a magnet was pre-cooled and positioned in a spray-drying tower. Carbonyl iron powder (CIP) was added to the drying media to increase the sampling mass by the magnetic effect. During drying, a temperature sensor measured the particle contact temperature. After drying, the sample in the sampling device was taken out to analyze the characteristics, including the mass, water content, and bacteria livability in the sample. The sampling device and method were optimized with a sampling cup with a depth of 3.5 cm (for contact temperatures below 79.1°C) or 5 cm (for contact temperatures below 89.1°C). The ratio of CIP to reconstituted skim milk (RSM) was 1:10, and RSM concentration was not lower than 20% (w/w). This method was then applied to spray drying of Lactobacillus bulgaricus sp1.1. Furthermore, it was demonstrated that 2 mL of sterile water placed in the sampling cup prior to drying resulted in a more accurate measurement of cell viability. This sampling method can be used in practical spray drying applications for biological materials without using a special instrument or drying tower. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to evaluate the antibiotic susceptibility of lactic acid bacteria (LAB) and coagulase‐negative staphylococci (CNS) strains isolated from naturally fermented smoked pork produced in Hunan, China. A total of 48 strains were isolated by selective medium and identified at the species level by 16S rRNA gene sequencing as follows: Staphylococcus carnosus (23), Lactobacillus plantarum (12), Lactobacillus brevis (10), Lactobacillus sakei (1), Weissella confusa (1), and Weissella cibaria (1). All strains were typed by RAPD‐PCR, and their susceptibility to 15 antibiotics was determined and expressed as the minimum inhibitory concentration (MIC) using agar dilution method. High resistance to penicillin G, streptomycin, gentamycin, vancomycin, chloramphenicol, norfloxacin, ciprofloxacin, kanamycin, and neomycin was found among the isolates. All the strains were sensitive to ampicillin, while the susceptibility to tetracycline, oxytetracycline, erythromycin, lincomycin, and roxithromycin varied. The presence of relevant resistance genes was investigated by PCR and sequencing, with the following genes detected: str(A), str(B), tet(O), tet(M), ere(A), and catA. Eleven strains, including 3 S. carnosus, 6 L. plantarum, and 2 L. brevis, harbored more than 3 antibiotic resistance genes. Overall, multiple antibiotic resistance patterns were widely observed in LAB and S. carnosus strains isolated from Hunan smoked pork. Risk assessment should be carried out with regard to the safe use of LAB and CNS in food production. Practical Application: We evaluated the antibiotic resistance of lactic acid bacteria and coagulase‐negative staphylococci strains isolated from Chinese naturally fermented smoked pork. Our results may provide important data on establishing breakpoint standards for LAB and CNS and evaluating the safety risk of these strains for commercial use. [ABSTRACT FROM AUTHOR]

Dates are commercially consumed as semi-dried fruit or processed into juice and puree for further food production. However, the date residue after juice and puree production is not used, although it appears to be nutrient enriched. Here, date residue was fermented by a lactic acid bacterium, Lactobacillus brevis , which has been generally recognized as safe. Through degradation of sodium glutamate added to the residue during the fermentation, γ-aminobutyric acid (GABA), which reduces neuronal excitability, was produced at the conversion rate of 80–90% from glutamate. In order to achieve this GABA production level, pretreatment of the date residue with carbohydrate-degrading enzymes, i.e., cellulase and pectinase, was necessary. All ingredients used for this GABA fermentation were known as being edible. These results provide us with a solution for the increasing commercial demand for GABA in food industry with the use of date residue that has been often discarded. [ABSTRACT FROM AUTHOR]

An efficient bioprocess using immobilized lactic acid bacteria to obtain 5-iodouracil-2′-deoxyriboside, known as idoxuridine, is reported. This nucleoside analogue is an antiviral agent used in the treatment of viral infections in the absence of efficient vaccines. Idoxuridine conversion was close to 90% in different nonconventional media. A bionanocomposite (alginate-nanoclay) was employed as matrix to stabilize Lactobacillus animalis ATCC 35046 with improved stability in the presence of organic cosolvents. In this study, an eco-compatible and alternative bioprocess to obtain idoxuridine was developed for the first time. The scale-up biosynthesis of idoxuridine afforded a product yield close to 0.4 gr/L in the presence of 20% of DMSO. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the influence of different starch liberation and saccharification methods on microbiological contamination of distillery mashes. Moreover, the effect of hop α-acid preparation for protection against microbial infections was assessed. The quality of agricultural distillates was also evaluated. When applying the pressureless liberation of starch (PLS) and malt as a source of amylolytic enzymes, the lactic acid bacteria count in the mashes increased several times during fermentation. The mashes obtained using the pressure-thermal method and malt enzymes revealed a similar pattern. Samples prepared using cereal malt exhibited higher concentrations of lactic and acetic acids, as compared to mashes prepared using enzymes of microbial origin. The use of hop α-acids led to the reduction of bacterial contamination in all tested mashes. As a result, fermentation of both mashes prepared with microbial origin enzyme preparations and with barley malt resulted in satisfactory efficiency and distillates with low concentrations of aldehydes. [ABSTRACT FROM AUTHOR]

Acidified wort produced biologically using lactic acid bacteria (LAB) has application during sour beer production and in breweries adhering to the German purity law ( Reinheitsgebot). LAB cultures, however, suffer from end product inhibition and low pH, leading to inefficient lactic acid (LA) yields. Three brewing-relevant LAB ( Pediococcus acidilactici AB39, Lactobacillus amylovorus FST2.11 and Lactobacillus plantarum FST1.7) were examined during batch fermentation of wort possessing increasing buffering capacities (BC). Bacterial growth was progressively impaired when exposed to higher LA concentrations, ceasing in the pH range of 2.9-3.4. The proteolytic rest (50°C) during mashing was found to be a major factor improving the BC of wort. Both a longer mashing profile and the addition of an external protease increased the BC (1.21 and 1.24, respectively) compared with a control wort (1.18), and a positive, linear correlation ( R2 = 0.957) between free amino nitrogen and BC was established. Higher levels of BC led to significant greater LA concentration (up to +24%) after 48 h of fermentation, reaching a maximal value of 11.3 g/L. Even higher LA (maximum 12.8 g/L) could be obtained when external buffers were added to wort, while depletion of micronutrient(s) (monosaccharides, amino acids and/or other unidentified compounds) was suggested as the cause of LAB growth cessation. Overall, a significant improvement in LA production during batch fermentation of wort is possible when BC is improved through mashing and/or inclusion of additives (protease and/or external buffers), with further potential for optimization when strain-dependent nutritional requirements, e.g. sugar and amino acids, are considered. Copyright © 2017 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Hardaliye is a lactic acid fermented beverage produced from red grape or grape juice with addition of crushed mustard seeds and benzoic acid and it is widely produced and consumed in the Thrace region of Turkey. The aim of this study was to determine the dominant lactic acid bacteria (LAB) species found in hardaliye and to investigate their technological properties related to probiotic action and potential use as a starter culture for production of hardaliye. For this aim; LAB were isolated from 28 hardaliye samples (23 hardaliye samples that were obtained from different regions of Kirklareli, Turkey and 5 hardaliye samples were produced by using traditional methods in laboratory conditions). After carrying out conventional and molecular biological methods, it was found that all LAB species isolated belonged to genus Lactobacillus. The dominant species in the microbiota was found to be Lactobacillus plantarum while around 98% of the isolates were similar to each other. Therefore, it was well understood that a small diversity of LAB strains played role during the fermentation process. The results of this study revealed that the isolates had the potential to be used as starter cultures in hardaliye production due to their antimicrobial effects and acid production capabilities. [ABSTRACT FROM AUTHOR]

Spray-drying of lactic cultures provides direct-to-vat starters, which facilitate their commercialization and use. However, this process may alter the metabolic activity and deteriorate technological features. In this work, we assessed the influence of spray-drying on the survival and aroma production of two strains of mesophilic lactobacilli: Lactobacillus paracasei 90 and Lactobacillus plantarum 91, which have already been characterized as good adjunct cultures. The spray-drying was carried out using a laboratory scale spray and the dried cultures were monitored during the storage for the survival rate. The dried cultures were applied to two cheese models: sterile cheese extract and miniature soft cheese. The influence on the carbohydrate metabolism and the production of organic acids and volatile compounds was determined. Both strains retained high levels of viable counts in the powder after drying and during the storage at 5 °C for twelve months. In addition, they also remained at high level in both cheese models during incubation or ripening. Similar profiles of carbohydrate fermentation and bioformation of volatile compounds were observed in the cheese extracts for each of the strains when tested as both fresh and dried cultures. In addition, the ability of Lb. paracasei 90 to increase the production of acetoin and diacetyl remarkably in cheese models was also confirmed for the spray-dried culture. [ABSTRACT FROM AUTHOR]

Aims To determine the effect of three different freezing temperatures on post-freeze-drying survival rates of wine yeasts and lactic acid bacteria ( LAB). To know if a similar freeze-drying protocol can be used for both micro-organisms. Methods and Results Cells from liquid culture media were recovered and concentrated in appropriate lyoprotectants. Aliquots of each strain were frozen at −20, −80 and −196°C before vacuum drying. Viable cell counts were done before freezing and after freeze-drying. Survival rates were calculated. Freezing temperatures differently affected yeast and bacteria survival. The highest survival rates were obtained at −20 and −80°C for yeasts, but at −196°C for LAB. Major differences in survival rates were recorded among freeze-dried yeasts, but were less drastic for LAB. Yeasts Pichia membranifaciens, Starmerella bacillaris and Metschnikowia pulcherrima, and LAB Lactobacillus paracasei, Pediococcus parvulus and Lactobacillus mali, were the most tolerant species to freeze-drying, regardless of freezing temperature. Conclusions Yeast and LAB survival rates differed for each tested freezing temperature. For yeasts, −20°C ensured the highest post-freeze-drying viability and −196°C for LAB. Significance and Impact of the Study Freezing temperature to freeze-dry cells is a crucial factor for ensuring good wine yeast and LAB survival. These results are important for appropriately preserving micro-organisms and for improving starter production processes. [ABSTRACT FROM AUTHOR]

Studies on the health-promoting effects of lactic acid bacteria (LAB) are numerous, but few provide examples of the relationship between LAB function and culture conditions. We verified the effect of differences in culture conditions on Lactobacillus plantarum OLL2712 functionality; this strain exhibits anti-inflammatory activity and preventive effects against metabolic disorders. We measured interleukin-10 (IL-10) and IL-12 production in murine immune cells treated with OLL2712 cells prepared under various culture conditions. The results showed that the IL-10-inducing activities of OLL2712 cells on murine immune cells differed dramatically between OLL2712 groups at different culture phases and using different culture medium components, temperatures, and neutralizing pHs. In particular, exponential-phase cells had much more IL-10-inducing activity than stationary-phase cells. We confirmed that the Toll-like receptor 2 (TLR2) stimulation activity of OLL2712 cells depended on culture conditions in conjunction with IL-10-inducing activity. We also demonstrated functional differences by culture phases in vivo; OLL2712 cells at exponential phase had more anti-inflammatory activity and anti-metabolic-disorder effects on obese and diabetic mice than those by their stationary-phase counterparts. These results suggest that culture conditions affect the functionality of antiinflammatory LAB. IMPORTANCE While previous studies demonstrated that culture conditions affected the immunomodulatory properties of lactic acid bacteria (LAB), few have comprehensively investigated the relationship between culture conditions and LAB functionality. In this study, we demonstrated several culture conditions of Lactobacillus plantarum OLL2712 for higher anti-inflammatory activity. We also showed that culture conditions concretely influenced the health-promoting functions of OLL2712 in vivo, particularly against metabolic disorders. Further, we characterized a novel mechanism by which changing LAB culture conditions affected immunomodulatory properties. Our results suggest that culture condition optimization is important for the production of LAB with anti-inflammatory activity. [ABSTRACT FROM AUTHOR]

Lactobacillus plantarum is a lactic acid bacterium that can degrade food tannins by the successive action of tannase and gallate decarboxylase enzymes. In the L. plantarum genome, the gene encoding the catalytic subunit of gallate decarboxylase (lpdC, or lp_2945) is only 6.5 kb distant from the gene encoding inducible tannase (L. plantarum tanB [tanBLp], or lp_2956). This genomic context suggests concomitant activity and regulation of both enzymatic activities. Reverse transcription analysis revealed that subunits B (lpdB, or lp_0271) and D (lpdD, or lp_0272) of the gallate decarboxylase are cotranscribed, whereas subunit C (lpdC, or lp_2945) is cotranscribed with a gene encoding a transport protein (gacP, or lp_2943). In contrast, the tannase gene is transcribed as a monocistronic mRNA. Investigation of knockout mutations of genes located in this chromosomal region indicated that only mutants of the gallate decarboxylase (subunits B and C), tannase, GacP transport protein, and TanR transcriptional regulator (lp_2942) genes exhibited altered tannin metabolism. The expression profile of genes involved in tannin metabolism was also analyzed in these mutants in the presence of methyl gallate and gallic acid. It is noteworthy that inactivation of tanR suppresses the induction of all genes overexpressed in the presence of methyl gallate and gallic acid. This transcriptional regulator was also induced in the presence of other phenolic compounds, such as kaempferol and myricetin. This study complements the catalog of L. plantarum expression profiles responsive to phenolic compounds, which enable this bacterium to adapt to a plant food environment. IMPORTANCE Lactobacillus plantarum is a bacterial species frequently found in the fermentation of vegetables when tannins are present. L. plantarum strains degrade tannins to the less-toxic pyrogallol by the successive action of tannase and gallate decarboxylase enzymes. The genes encoding these enzymes are located close to each other in the chromosome, suggesting concomitant regulation. Proteins involved in tannin metabolism and regulation, such GacP (gallic acid permease) and TanR (tannin transcriptional regulator), were identified by differential gene expression in knockout mutants with mutations in genes from this region. This study provides insights into the highly coordinated mechanisms that enable L. plantarum to adapt to plant food fermentations. [ABSTRACT FROM AUTHOR]

Volatile compounds in fermented sourdoughs were formed by using starter cultures [Lactobacillus brevis (St-I), Lactobacillus fermentum (St-II) and Lactobacillus plantarum (St-III)] along with control starter culture (Saccharomyces cerevisiae). Sourdough samples were obtained by fermenting the dough with starter cultures at different fermentation times (12, 18 and 24 hrs). Furthermore, the fermented samples were analyzed for pH, total titratable acidity (TTA), organic acids, sugars and volatile compounds. From the results, it is noticed that the pH decreased as a function of fermentation time in all starter cultures and maximum pH drop was observed in St-II after 24 h of fermentation followed by St-I at the same time interval. However, least drop in pH was recorded in the control starter culture. Moreover, highest TTA (10.30%) was produced by St-I after 24 h of fermentation followed by the same culture at 18 h of fermentation (9.90%). Conversely, the control samples yielded lowest TTA. In case of organic acids and sugars after evaluating by HPLC depicted that St-I gave more concentrations of sugar fractions (maltose and fructose) and St-II produce higher concentrations of organic acids, all sugar contents and organic acids increased with passage of time. Sourdough samples were analyzed for volatile compounds by GC-MS through headspace analysis. Sourdough produced by the addition of starter cultures yielded 1-hexanol, hexanal, octanal and ethyl acetate in general whereas, diacetyl was produced in St-III ferments only. [ABSTRACT FROM AUTHOR]

Weissella are obligate heterofermentative lactic acid bacteria belonging to the Leuconostocaceae family. Some Weissella can be found in salted and fermented foods, such as kimchi and jeotgal, and plays an important role in the fermentation process. In the present study, for the first time, a rapid and accurate identification method for Weissella species from kimchi and jeotgal was developed based on MALDI-TOF MS, supplemented with an in-house database. Of the 135 Weissella spectra aligned with the MALDI bioTyper database, 56 isolates (41.5%) yielded no reliable identification results with low log scores (< 1.7). After registering the spectra of six Weissella reference strains, all of the isolates were correctly identified, of which 113 (83.7%) and 22 (16.3%) were identified at the species and genus level, respectively. Moreover, a dendrogram generated by protein profiles of the different Weissella species clearly presented distinctive clusters, and PCA analysis separated the spectra of Weissella species into four clusters. In comparing food origins, different Weissella species were identified from two fermented foods. W. soli and W. cibaria were isolated from kimchi, while W. thailandensis and W. halotolerans were isolated from jeotgal. The results of our proteomic approach confirm that the MALDI bioTyper database, with our in-house Weissella database, is sufficient for Weissella identification. The MALDI-TOF MS method provides fast and reliable discrimination between different species in the genus Weissella and, therefore, will be useful for safety control in fish farms or in the production of fermented foods. This method can also be applied to the control of opportunistic pathogenic Weissella in human clinical infections. [ABSTRACT FROM AUTHOR]

In the last two decades knowledge on lactic acid bacteria (LAB) associated with wine has increased considerably. Investigations on genetic and biochemistry of species involved in malolactic fermentation, such as Oenococcus oeni and of Lactobacillus have enabled a better understand of their role in aroma modification and microbial stability of wine. In particular, the use of molecular techniques has provided evidence on the high diversity at species and strain level, thus improving the knowledge on wine LAB taxonomy and ecology. These tools demonstrated to also be useful to detect strains with potential desirable or undesirable traits for winemaking purposes. At the same time, advances on the enzymatic properties of wine LAB responsible for the development of wine aroma molecules have been undertaken. Interestingly, it has highlighted the high intraspecific variability of enzymatic activities such as glucosidase, esterase, proteases and those related to citrate metabolism within the wine LAB species. This genetic and biochemistry diversity that characterizes wine LAB populations can generate a wide spectrum of wine sensory outcomes. This review examines some of these interesting aspects as a way to elucidate the link between LAB diversity with wine aroma and flavour. In particular, the correlation between inter- and intra-species diversity and bacterial metabolic traits that affect the organoleptic properties of wines is highlighted with emphasis on the importance of enzymatic potential of bacteria for the selection of starter cultures to control MLF and to enhance wine aroma. [ABSTRACT FROM AUTHOR]

The present study investigates the changes in intestinal histomorphology, autochthonous microbiota and growth performance of the oscar, Astronotus ocellatus, following dietary administration of different levels of xylooligosaccharide ( XOS). One hundred forty-four oscars (8.88 ± 0.23 g; n = 144) were randomly stocked in 12 aquaria (100-L) assigned to four treatments repeated in triplicate. Fish were fed a commercial diet, Biomar, supplemented with different levels (0 [control], 0.5, 1, 2%) of XOS for 8 weeks. Treatments were investigated under static aerated water conditions with a 70% daily water exchange. Evaluation of intestinal histomorphology (villus height, enterocytes height and thickness of the tunica muscularis) revealed no significant differences between XOS-fed groups and the control treatment (P > 0.05). However, administration of XOS in the oscar diet increased the total autochthonous intestinal heterotrophic bacteria significantly (P < 0.05). Autochthonous lactic acid bacteria levels were also significantly elevated in XOS-fed groups (P < 0.05). Furthermore, dietary XOS remarkably increased growth performance (control: 22.76 ± 2.79, 2% XOS: 29.13 ± 2. 8; n = 12) parameters of the oscar (P < 0.05). These results demonstrated the beneficial effects of XOS on the growth performance and intestinal microbiota of A. ocellatus. [ABSTRACT FROM AUTHOR]

Natural lactic acid bacteria (LAB) populations in tropical grasses and their fermentation characteristics on silage prepared with cellulase enzyme and LAB inoculants were studied. A commercial inoculant Lactobacillus plantarum Chikuso 1 (CH), a local selected strain Lactobacillus casei TH14 (TH14), and 2 cellulases, Acremonium cellulase (AC) and Maicelase (MC; Meiji Seika Pharma Co. Ltd., Tokyo, Japan), were used as additives to silage preparation with fresh and wilted (6 h) Guinea grass and Napier grass. Silage was prepared using a laboratory-scale fermentation system. Treatments were CH, TH14, AC at 0.01% fresh matter, AC 0.1%, MC 0.01%, MC 0.1%, CH+AC 0.01%, CH+AC 0.1%, CH+MC 0.01%, CH+MC 0.1%, TH14+AC 0.1%, TH14+AC 0.01%, TH14+MC 0.1%, and TH14+MC 0.01%. Microorganism counts of Guinea grass and Napier grass before ensiling were 102 LAB and 106 aerobic bacteria; these increased during wilting. Based on morphological and biochemical characteristics, and 16S rRNA gene sequence analysis, natural strains from both grasses were identified as L. plantarum, L. casei, Lactobacillus acidipiscis, Leuconostoc pseudomesenteroides, Leuconostoc garlicum, Weissella confusa, and Lactococcus lactis. Lactobacillus plantarum and L. casei are the dominant species and could grow at lower pH and produce more lactic acid than the other isolates. Crude protein and neutral detergent fiber were 5.8 and 83.7% of dry matter (DM) for Guinea grass, and 7.5 and 77.1% of DM for Napier grass. Guinea grass had a low level of water-soluble carbohydrates (0.39% of DM). Guinea grass silage treated with cellulase had a lower pH and higher lactic acid content than control and LAB treatments. The 0.1% AC and MC treatments had the best result for fermentation quality. All high water-soluble carbohydrate (2.38% DM) Napier grass silages showed good fermentation quality. Compared with control and LAB-inoculated silage, the cellulasetreated silages had significantly higher crude protein content and lower neutral detergent fiber and acid detergent fiber contents. The results confirmed that cellulase could improve tropical silage quality, inhibiting protein degradation and promoting fiber degradation. [ABSTRACT FROM AUTHOR]

The application of correct numbers of viable microorganisms to forages at the time of ensiling is one of the most important factors affecting the probability of a beneficial effect from an inoculant. The objective of this study was to determine relationships between numbers of expected lactic acid bacteria (LAB) from silage inoculants in application tanks and various factors that might affect their viability. The pH and temperature of inoculant-water mixes were measured in applicator tanks (n = 53) on farms in Wisconsin, Minnesota, South Dakota, and California during the corn harvest season of 2012. Samples were collected on-farm and plated on de Man, Rogosa, and Sharpe agar to enumerate LAB and establish the number of viable LAB (cfu/mL). Expected numbers of LAB were calculated from the minimum label guarantees for viable bacteria and mixing rates with water. In addition, the pH of the inoculant-water mixes at sampling, the ambient temperature at sampling, and the length of time that the samples had been in the tank were measured and obtained. The log difference between the measured and expected numbers of LAB was calculated and expressed as ΔM - E in log scale. Ambient temperature at sampling had no relationship with time in the tank or ΔM - E. Most (83%) of the inoculants had been mixed with water in the applicator tanks for <10 h. For these samples, a negative linear correlation (R2 = 0.36) existed between time that the inoculant-water mixes were in the applicators tanks and ΔM - E. The pH of the inoculant-water mixes was also negatively correlated (R2 = 0.28) with time in the applicator tank, but pH was not related to ΔM - E. The temperatures of the inoculant-water mixtures were negatively correlated with ΔM - E (R2 = 0.39). Seven of 8 samples whose ΔM - E were at least -0.95 or more lower than expected (equivalent of about 1 or more log concentration less than expected) had water temperatures above 35°C. These data support our previous laboratory findings and suggest that high temperatures of inoculant-water mixes have the potential to negatively affect the final application rate of some inoculants, which may affect their overall effectiveness to improve silage fermentation. [ABSTRACT FROM AUTHOR]

Background: Lactic acid bacteria (LAB) are part of the gut microbiota and produce ribosomally synthesized antimicrobial peptides or bacteriocins with interest as natural food preservatives and therapeutic agents. Bacteriocin-producing LAB are also attractive as probiotics. Griffon vultures (Gyps fulvus subspecies fulvus) are scavenger birds that feed almost exclusively on carrion without suffering apparent ill effects. Therefore, griffon vultures might be considered a reservoir of bacteriocinproducing lactic acid bacteria (LAB) with potential biotechnological applications. Results: Griffon vulture feces were screened for LAB with antimicrobial activity, genes encoding bacteriocins, potential virulence determinants, susceptibility to antibiotics, genotyping and characterization of bacteriocins. In this study, from 924 LAB evaluated 332 isolates (36 %) showed direct antimicrobial activity against Gram-positive bacteria only. The molecular identification of the most antagonistic 95 isolates showed that enterococci was the largest LAB group with antimicrobial activity (91 %) and E. faecium (40 %) the most identified antagonistic species. The evaluation of the presence of bacteriocin structural genes in 28 LAB isolates with the highest bacteriocinogenic activity in their supernatants determined that most enterococcal isolates (75 %) encoded multiple bacteriocins, being enterocin A (EntA) the largest identified (46 %) bacteriocin. Most enterococci (88 %) were resistant to multiple antibiotics. ERIC-PCR and MLST techniques permitted genotyping and recognition of the potential safety of the bacteriocinogenic enterococci. A multiple-step chromatographic procedure, determination of the N-terminal amino acid sequence of purified bacteriocins by Edman degradation and a MALDI TOF/TOF tandem MS procedure permitted characterization of bacteriocins present in supernatants of producer cells. Conclusions: Enterococci was the largest LAB group with bacteriocinogenic activity isolated from griffon vulture feces. Among the isolates, E. faecium M3K31 has been identified as producer of enterocin HF (EntHF), a bacteriocin with remarkable antimicrobial activity against most evaluated Listeria spp. and of elevated interest as a natural food preservative. E. faecium M3K31 would be also considered a safe probiotic strain for use in animal nutrition. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) can interfere with pathogens through different mechanisms; one is the production of biosurfactants, a group of surface-active molecules, which inhibit the growth of potential pathogens. In the present study, biosurfactants produced by Lactobacillus reuteri DSM 17938, Lactobacillus acidophilus DDS-1, Lactobacillus rhamnosus ATCC 53103, and Lactobacillus paracasei B21060 were dialyzed (1 and 6 kDa) and characterized in term of reduction of surface tension and emulsifying activity. Then, aliquots of the different dialyzed biosurfactants were added to Streptococcus mutans ATCC 25175 and Streptococcus oralis ATCC 9811 in the culture medium during the formation of biofilm on titanium surface and the efficacy was determined by agar plate count, biomass analyses, and flow cytometry. Dialyzed biosurfactants showed abilities to reduce surface tension and to emulsifying paraffin oil. Moreover, they significantly inhibited the adhesion and biofilm formation on titanium surface of S. mutans and S. oralis in a dose-dependent way, as demonstrated by the remarkable decrease of cfu/ml values and biomass production. The antimicrobial properties observed for dialyzed biosurfactants produced by the tested lactobacilli opens future prospects for their use against microorganisms responsible of oral diseases. [ABSTRACT FROM AUTHOR]

The consumption of lactic acid bacteria capable of binding or degrading food-borne carcinogens may reduce human exposure to these deleterious compounds. In this study, 25 Lactobacillus strains isolated from human, plant, or dairy environments were investigated for their potential probiotic capacity against perfluorooctanoate (PFOA) toxicity. The PFOA binding, tolerance ability, and acid and bile salt tolerance were investigated and assessed by principal component analysis. Additionally, the effect of different pH levels and binding times was assessed. These strains exhibited different degrees of PFOA binding; the strain with the highest PFOA binding capability was Lactobacillus plantarum CCFM738, which bound to 49.40 ± 1.5 % of available PFOA. This strain also exhibited relatively good cellular antioxidative properties, acid and bile salt tolerance, and adhesion to Caco-2 cells. This study suggests that L. plantarum CCFM738 could be used as a potential probiotic in food applications against PFOA toxicity. [ABSTRACT FROM AUTHOR]

In the last two decades, there has been increasing evidence supporting the role of the intestinal microbiota in health and disease, as well as the use of probiotics to modulate its activity and composition. Probiotic bacteria selected for commercial use in foods, mostly lactic acid bacteria and bifidobacteria, must survive in sufficient numbers during the manufacturing process, storage, and passage through the gastro-intestinal tract. They have several modes of action and it is crucial to unravel the mechanisms underlying their postulated beneficial effects. To track their survival and persistence, and to analyse their interaction with the gastro-intestinal epithelia it is essential to discriminate probiotic strains from endogenous microbiota. Fluorescent reporter proteins are relevant tools that can be exploited as a non-invasive marker system for in vivo real-time imaging in complex ecosystems as well as in vitro fluorescence labelling. Oxygen is required for many of these reporter proteins to fluoresce, which is a major drawback in anoxic environments. However, some new fluorescent proteins are able to overcome the potential problems caused by oxygen limitations. The current available approaches and the benefits/disadvantages of using reporter vectors containing fluorescent proteins for labelling of bacterial probiotic species commonly used in food are addressed. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) are promising vectors of choice to deliver active molecules to mucosal tissues. They are recognized as safe by the World Health Organization and some strains have probiotic properties. The wide range of potential applications of LAB-driven mucosal delivery includes control of inflammatory bowel disease, vaccine delivery, and management of auto-immune diseases. Because of this potential, strategies for the display of proteins at the surface of LAB are gaining interest. To display a protein at the surface of LAB, a signal peptide and an anchor domain are necessary. The recombinant protein can be attached to the membrane layer, using a transmembrane anchor or a lipoprotein-anchor, or to the cell wall, by a covalent link using sortase mediated anchoring via the LPXTG motif, or by non-covalent liaisons employing binding domains such as LysM or WxL. Both the stability and functionality of the displayed proteins will be affected by the kind of anchor used. The most commonly surfaced exposed recombinant proteins produced in LAB are antigens and antibodies and the most commonly used LAB are lactococci and lactobacilli. Although it is not necessarily so that surface-display is the preferred localization in all cases, it has been shown that for certain applications, such as delivery of the human papillomavirus E7 antigen, surface-display elicits better biological responses, compared to cytosolic expression or secretion. Recent developments include the display of peptides and proteins targeting host cell receptors, for the purpose of enhancing the interactions between LAB and host. Surfacedisplay technologies have other potential applications, such as degradation of biomass, which is of importance for some potential industrial applications of LAB. [ABSTRACT FROM AUTHOR]

It is tempting to look at bacteria from our human egocentric point of view and label them as either 'good' or 'bad'. However, a microbial society has its own system of government -- 'microcracy' -- and its own rules of play. Lactic acid bacteria are often referred to as representatives of the good ones, and there is little doubt that those belonging to the normal intestinal flora are beneficial for human health. But we should stop thinking of lactic acid bacteria as always being 'friendly' -- they may instead behave like fledgling cuckoos. [ABSTRACT FROM AUTHOR]

In this study, acid- and bile-tolerant yeast and lactic acid bacteria (LAB) were isolated from Inner Mongolian cheeses ( khuruud, zȍȍkhii, tsur ) and an alcoholic drink ( saaliin arhi ) and its starter ( khȍrȍnggȍ ), and the alcohol-brewing capacities of the isolates were tested. Among 69 yeast and 89 LAB isolates, 6 typical yeast (5 Saccharomyces cerevisiae and 1 Naumovozyma castellii ) and 6 LAB ( Lactobacillus plantarum ) strains were selected on the basis of acid tolerance (pH 3.5), bile tolerance, and/or lactose fermentation properties. The selected yeasts, particularly the S. cerevisiae SY1 strain isolated from khȍrȍnggȍ , produced high levels of ethanol in both a small Japanese sake brewing model and in grape juice fermentation. Among the selected L. plantarum strains, ZL1 and KL1, isolated from zȍȍkhii and Saaliin arhi, respectively, showed weak and strong lactose fermentation in milk. Although a monoculture of S. cerevisiae SY1 could not produce ethanol during milk fermentation, it produced high levels of ethanol in a co-culture with L. plantarum strain ZL1. In contrast, in co-culture with a more vigorous lactose fermenter, strain KL1, S. cerevisiae SY1 was not able to produce a comparable level of ethanol. These results demonstrate co-fermentation roles for yeast and LAB in traditional fermented dairy foods. [ABSTRACT FROM AUTHOR]

Lactobacillus spp. from Mexican Cocido cheese were shown to produce bacteriocin-like substances (BLS) active against Staphylococcus aureus, Listeria innocua, Escherichia coli, and Salmonella typhimurium by using the disk diffusion method. Crude extracts of Lactobacillus fermentum showed strong inhibitory activity against Staph. aureus, L. innocua, E. coli, and Salmonella cholerae. Complete inactivation of antimicrobial activity was observed after treatment of crude extracts with proteinase K, pronase, papain, trypsin, and lysozyme, confirming their proteinaceous nature. However, antimicrobial activity was partly lost for some of the crude extracts when treated with α-amylase, indicating that carbohydrate moieties were involved. The antimicrobial activity of the crude extracts was stable at 65°C for 30 min over a wide pH range (2-8), and addition of potassium chloride, sodium citrate, ethanol, and butanol did not affect antibacterial activity. However, antimicrobial activity was lost after heating at 121°C for 15 min, addition of methanol or Tween 80. Fourteen out of 18 Lactobacillus spp. showed antimicrobial activity against different test microorganisms, and 12 presented bacteriocin-like substances. Generation time and growth rate parameters indicated that the antimicrobial activity of crude extracts from 3 different strains was effective against the 4 indicator microorganisms. One of the crude extracts showed inhibition not only against gram-positive but also against gram-negative bacteria. Bacteriocin-like substances produced by this specific Lactobacillus strain showed potential for application as a food biopreservative. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) have a long history of safe exploitation by humans, being used for centuries in food production and preservation and as probiotic agents to promote human health. Interestingly, some species of these Gram-positive bacteria, which are generally recognized as safe organisms by the US Food and Drug Administration (FDA), are able to survive through the gastrointestinal tract (GIT), being capable to reach and colonize the intestine, where they play an important role. Besides, during the last decades, an important effort has been done for the development of tools to use LAB as microbial cell factories for the production of proteins of interest. Given the need to develop effective strategies for the delivery of prophylactic and therapeutic molecules, LAB have appeared as an appealing option for the oral, intranasal and vaginal delivery of such molecules. So far, these genetically modified organisms have been successfully used as vehicles for delivering functional proteins to mucosal tissues in the treatment of many different pathologies including GIT related pathologies, diabetes, cancer and viral infections, among others. Interestingly, the administration of such microorganisms would suppose a significant decrease in the production cost of the treatments agents since being live organisms, such vectors would be able to autonomously amplify and produce and deliver the protein of interest. In this context, this review aims to provide an overview of the use of LAB engineered as a promising alternative as well as a safety delivery platform of recombinant proteins for the treatment of a wide range of diseases. [ABSTRACT FROM AUTHOR]

The goal of this study was to assess the potential of fermented Cudrania tricuspidata leaf (CTL) aqueous extract as a functional food material. The CTL aqueous extract was fermented using lactic acid bacteria (LAB) isolated from soybean-fermented foods and the biological effects of the resultant fermented extracts on MG-63 human osteoblastic cells and 3T3-L1 mouse pre adipocytes were examined in vitro. We found that (1) the radical scavenging activities of CTL extracts fermented by various LAB strains (fermented CTL, F-CTL) were ~2- fold higher than that of non-fermented CTL extract (NFCTL), (2) F-CTL extract enhanced MG-63 cell proliferation compared to NF-CTL-treated cells, (3) the level of alkaline phosphatase activity in F-CTL-treated MG-63 cells was significantly higher than that in NF-CTL-treated cells, and (4) 3T3-L1 cell differentiation was dramatically decreased by F-CTL treatment, but not by NF-CTL. These findings suggest that CTL that has undergone LAB-mediated fermentation may be beneficial for promoting osteogenic differentiation of osteoblastic cells and inhibiting fat accumulation in adipocytes. [ABSTRACT FROM AUTHOR]

Viral infections in the aquaculture of salmonids can lead to high mortality and substantial economic losses. Thus, there is industrial interest in new molecules active against these viruses. Here we describe the production, purification, and the physicochemical and structural characterization of high molecular weight dextrans synthesized by Lactobacillus sakei MN1 and Leuconostoc mesenteroides RTF10. The purified dextrans, and commercial dextrans with molecular weights ranging from 10 to 2000 kDa, were assayed in infected BF-2 and EPC fish cell-line monolayers for antiviral activity. Only T2000 and dextrans from MN1 and RTF10 had significant antiviral activity. This was similar to results obtained against infectious pancreatic necrosis virus. However the dextran from MN1 showed ten-fold higher activity against hematopoietic necrosis virus than T2000. In vivo assays using the MN1 polymer confirmed the in vitro results and revealed immunomodulatory activity. These results together with the high levels of dextran production (2 g L −1 ) by Lb. sakei MN1, indicate the compounds potential utility as an antiviral agent in aquaculture. [ABSTRACT FROM AUTHOR]

The cereal-based fermented food Egyptian Kishk constitutes a major source of high quality dietary nutrients for Upper Egyptians and is popular among all social strata. Lactic acid bacteria were one of the main flora which is responsible for fermentation. To-date, kishk is still traditional making and the diversity of LAB in Kishk has not been fully investigated and improving the Kishk throughout using selected cultures for its processing has never been established. In this work, LAB have been isolated from samples collect ed during traditional making the Kishk. The obtained results showed that the dominant lactic acid bacteria isolates were obligatory hetero- fermentative and Enterococci spp. The homofermentative LAB were found in the first steps of the fermentation. Homofermentative and facultative heterofermentative of lactobacilli were found in the first fermentation process steps and then- almost disappeared after that in Kishk. On the other hand obligatory hetero fermentative and Enterococci spp. were detected in all steps of kishk manufacturing while Lactococcus was a minor isolate during fermentation process. The majority of isolates are γ - haemolytic except one isolate of Enterococci spp. which was β haemolytic. There are significant differences (P ≤ 0.01) in organoleptic characteri stics (colour, taste, smell, texture, appearance) and overall acceptability among all isolates used to ferment the milk. Fifteen isolates that received the highest levels of overall organoleptic properties are selected as starter culture in improving the Kishk making. [ABSTRACT FROM AUTHOR]

Between July 2011 and May 2012, 1 6 pooled faecal samples were collected on eight occasions (40 fish/occasion) from Atlantic salmon fed two commercial diets in a farm in Tasmania, Australia. From a second Tasmanian farm, 12 pooled faecal samples were collected on three occasions (80 fish/occasion) from salmon fed four trial diets. From these samples a total of 160 lactic acid bacteria (LAB) were isolated on MRS agar. Strains were initially typed using PhP-LB plates (PhPlate, AB) and divided into common types (CTs). Strains which belonged to the same CT and found on numerous sampling occasions (n=73) were identified using 16S rRNA sequencing and tested for cytotoxins production, bacteriocins, adherence to Atlantic salmon kidney cells as well as competitively exclude 16 bacterial strains in vitro. These strains were also tested for their resistance against nine antibiotics commonly used in Aquaculture. The 73 LAB strains belonged to six species namely Enterococcus casseliflavus, E. faecalis, E. faecium, Pediococcus acidilactici, and Weisella hellenica of which, three different strains of W. hellenica and one P. acidilactici met most criteria including medium to high adherence and pathogen exclusion capability in vitro. The potential of these strains to serve as probiotic candidates is discussed. [ABSTRACT FROM AUTHOR]

The effect of natural and lactic acid bacteria ( LAB) fermentation processes on metabolite changes in pastes of soybeans and soybean-maize blends was studied. Pastes composed of 100% soybeans, 90% soybeans and 10% maize, and 75% soybeans and 25% maize were naturally fermented ( NFP), and were fermented by lactic acid bacteria ( LFP). LAB fermentation processes were facilitated through back-slopping using a traditional fermented gruel, thobwa as an inoculum. Naturally fermented pastes were designated 100S, 90S, and 75S, while LFP were designated 100 SBS, 90 SBS, and 75 SBS. All samples, except 75 SBS, showed highest increase in soluble protein content at 48 h and this was highest in 100S (49%) followed by 90 SBS (15%), while increases in 100 SBS, 90S, and 75S were about 12%. Significant ( P < 0.05) increases in total amino acids throughout fermentation were attributed to cysteine in 100S and 90S; and methionine in 100S and 90 SBS. A 3.2% increase in sum of total amino acids was observed in 75 SBS at 72 h, while decreases up to 7.4% in 100 SBS at 48 and 72 h, 6.8% in 100S at 48 h and 4.7% in 75S at 72 h were observed. Increases in free amino acids throughout fermentation were observed in glutamate ( NFP and 75 SBS), GABA and alanine ( LFP). Lactic acid was 2.5- to 3.5-fold higher in LFP than in NFP, and other organic acids detected were acetate and succinate. Maltose levels were the highest among the reducing sugars and were two to four times higher in LFP than in NFP at the beginning of the fermentation, but at 72 h, only fructose levels were significantly ( P < 0.05) higher in LFP than in NFP. Enzyme activities were higher in LFP at 0 h, but at 72 h, the enzyme activities were higher in NFP. Both fermentation processes improved nutritional quality through increased protein and amino acid solubility and degradation of phytic acid (85% in NFP and 49% in LFP by 72 h). [ABSTRACT FROM AUTHOR]

Indigenous fermented milk products contain microbiota composed of technologically important species and strains which are gradually getting lost with new technologies. We investigated the microbial diversity in amabere amaruranu, a traditionally fermented milk product from Kenya. Sixteen samples of the product from different containers were obtained. One hundred and twenty isolates of lactic acid bacteria (LAB) and 67 strains of yeasts were identified using API 50 CH and API 20 C AUX identification kits, respectively. The average pH of all the traditional fermented samples was 4.00 ± 0.93. Lactobacilli, yeasts, and molds as well as Enterobacteriaceae counts from the plastic containers were significantly higher ( P < 0.05) than those from gourd. Enterobacteriaceae were below 1.00 ± 1.11 log10 cfu/mL in products from the gourds and 2.17 ± 1.92 log10 cfu/mL from the plastic containers. The LAB species were identified as Streptococcus thermophilus (25%), Lactobacillus plantarum (20%), and Leuconostoc mesenteroides (20%). The predominant yeasts were Saccharomyces cerevisiae (25%), Trichosporum mucoides (15%), Candida famata (10%), and Candida albicans (10%). The type of vessel used for fermentation had no significant influence on the type of isolated and identified species. The diverse mixture of LAB and yeasts microflora forms a potential consortium for further product innovation in amabere amaruranu and other fermented milk products. [ABSTRACT FROM AUTHOR]

2-Butanol has been an issue of industries in many areas, for example, biofuel production (as an advanced alternate fuel), fermented beverages, and food (as taste-altering component). Thus, its source of production, the biological pathway, and the enzymes involved are of high interest. In this study, 42 different isolates of lactic acid bacteria from nine different species were screened for their capability to consume meso-2,3-butanediol and produce 2-butanol. Lactobacillus brevis was the only species that showed any production of 2-butanol. Five of ten tested isolates of L. brevis were able to convert meso-2,3-butanediol to 2-butanol in a synthetic medium ( SM2). However, none of them showed the same capability in a complex medium such as MRS indicating that the ability to produce 2-butanol is subject to some kind of repression mechanism. Furthermore, by evaluating the performance of the enzymes required to convert meso-2,3-butanediol to 2-butanol, that is, the secondary alcohol dehydrogenase and the diol dehydratase, it was shown that the latter needed the presence of a substrate to be expressed. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, a YGNGV-motif-based assay was developed and applied. Given that there is an increasing demand for natural preservatives, we set out to obtain lactic acid bacteria (LAB) that produce bacteriocins against Gram-positive and Gram-negative bacteria. We here isolated 123 LAB strains from 5 types of traditional Chinese fermented food and screened them for the production of bacteriocins using the agar well diffusion assay (AWDA). Then, to acquire LAB producing class IIa bacteriocins, we used a YGNGV-motif-based assay that was based on 14 degenerate primers matching all class IIa bacteriocin-encoding genes currently deposited in NCBI. Eight of the LAB strains identified by AWDA could inhibit Gram-positive and Gram-negative bacteria; 5 of these were YGNGV-amplicon positive. Among these 5 isolates, amplicons from 2 strains (Y31 and Y33) matched class IIa bacteriocin genes. Strain Y31 demonstrated the highest inhibitory activity and the best match to a class IIa bacteriocin gene in NCBI, and was identified as Enterococcus faecium. The bacteriocin from Enterococcus avium Y33 was 100% identical to enterocin P. Both of these strains produced bacteriocins with strong antimicrobial activity against Listeria monocytogenes, Escherichia coli, and Bacillus subtilis, hence these bacteriocins hold promise as potential bio-preservatives in the food industry. These findings also indicated that the YGNGV-motif-based assay used in this study could identify novel class IIa bacteriocinogenic LAB, rapidly and specifically, saving time and labour by by-passing multiple separation and purification steps. [Copyright &y& Elsevier]

BACKGROUND Fermentation of vegetables and fruits is a traditional preservation technique, e.g. in Eastern Europe. Although usually spontaneous fermentation processes are applied, the addition of lactic acid bacteria ( LAB) starter cultures could accelerate processing and improve the consistency and quality of the end-products. RESULTS The application of Lactobacillus plantarum IMDO 788 as a starter culture strain for cauliflower and mixed vegetable fermentations resulted in accelerated acidification as compared with the spontaneous fermentations. The strain dominated the background microbiota throughout the process, whereas the spontaneous fermentations were characterised by widely variable species diversity. During the spontaneous fermentations, almost all carbohydrates were converted into lactic acid, ethanol, mannitol and acetic acid, indicating the participation of both heterofermentative and homofermentative LAB species. During the starter culture-added fermentations, residual carbohydrates were found and lactic acid and ethanol were the main end-metabolites. Vegetable-associated aromas, ethyl acetate and isoamyl acetate were produced during all fermentations. The high concentration of ethanol and the production of ethyl acetate and isoamyl acetate suggested the involvement of yeasts during all fermentations. CONCLUSION Lactobacillus plantarum IMDO 788 was an adequate starter culture strain for vegetable fermentations, prevailing over endogenous LAB communities. Further optimisation of the starter culture formulation is necessary to avoid yeast growth. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In the last few years the need to produce food with added value has fueled the search for new ingredients and health-promoting compounds. In particular, to improve the quality of bakery products with distinct nutritional properties, the identification of new raw materials, appropriate technologies, and specific microbial strains is necessary. In this study, different doughs were prepared, with 10% and 20% flour from immature wheat grain blended with type "0 America" wheat flour. Immature flour was obtained from durum wheat grains harvested 1 to 2 weeks after anthesis. Doughs were obtained by both the straight-dough and sourdough processes. Two selected exopolysaccharide-producing strains of lactic acid bacteria (LAB), Leuconostoc lactis A95 and Lactobacillus curvatus69B2, were used as starters. Immature flour contained 2.21 g/100 g (dry weight) of fructo-oligosaccharides. Twenty percent immature flour in dough resulted in a shorter leavening time (4.23 ± 0.03 h) than with the control and dough with 10% immature flour. The total titratable acidity of sourdough with 20% immature flour was higher (12.75 ± 0.15 ml 0.1 N NaOH) than in the control and sourdough with 10% immature wheat flour (9.20 ml 0.1 N NaOH). Molecular analysis showed that all samples contained three LAB species identified as L. lactis, L. curvatus, andPediococcus acidilactici. A larger amount of exopolysaccharide was found in sourdough obtained with 20% immature flour (5.33 ± 0.032 g/kg), positively influencing the exopolysaccharide content of the bread prepared by the sourdough process (1.70 ± 0.03 g/kg). The addition of 20% immature flour also led to a greater presence of fructo-oligosaccharides in the bread (900 mg/100 g dry weight), which improved its nutritional characteristics. While bread volume decreased as the concentration of immature wheat flour increased, its mechanical characteristics (stress at a strain of 30%) were the same in all samples obtained with different percentages of fructo-oligosaccharides. These data support the use of immature wheat grain flour, and exopolysaccaride-producing lactic acid bacteria in formulating functional prebiotic baked goods whose nutritional value can be suitably improved. [ABSTRACT FROM AUTHOR]

Yeasts and lactic acid bacteria (LAB) are commonly found in tempeh and has been studied separately. However, comprehensive study on population dynamics of yeasts and LAB during tempeh production, including the effect of the difference tempeh production methods has not been reported. This research was aimed in studying the effect of different methods of tempeh production applied in tempeh home industry on the dynamics of yeast and LAB communities. Population dynamics was expressed as both changes of colony number and its phylotype. Samples were obtained from five stages and from two different methods of tempeh production. Observations were carried out employing colony counting on selective media followed by Terminal Restriction Fragment Length Polymorphism (T-RFLP). The study indicated that the population of yeasts and LAB during tempeh production were dynamic and different between these methods. Tempeh production methods affected the presence of yeasts and LAB population as indicated by difference in colony number, the number and diversity of phylotype, as well as number of specific phylotypes grew on plates. [ABSTRACT FROM AUTHOR]

In this study, continuous operation of a pilot-scale upflow anaerobic sludge blanket (UASB) reactor for sewage treatment was conducted for 630 days to investigate the physical and microbial characteristics of the retained sludge. The UASB reactor with a working volume of 20.2 m³ was operated at ambient temperature (16-29 °C) and seeded with digested sludge. After 180 days of operation, when the sewage temperature had dropped to 20 °C or lower, the removal efficiency of both total suspended solids (TSS) and total biochemical oxygen demand (BOD) deteriorated due to washout of retained sludge. At low temperature, the cellulose concentration of the UASB sludge increased owing to the rate limitation of the hydrolytic reaction of suspended solids in the sewage. However, after an improvement in sludge retention (settleability and concentration) in the UASB reactor, the process performance stabilized and gave sufficient results (68% of TSS removal, 75% of total BOD removal) at an hydraulic retention time (HRT) of 9.7 h. The methanogenic activity of the retained sludge significantly increased after day 246 due to the accumulation of Methanosaeta and Methanobacterium following the improvement in sludge retention in the UASB reactor. Acid-forming bacteria from phylum Bacteroidetes were detected at high frequency; thus, these bacteria may have an important role in suspended solids degradation. [ABSTRACT FROM AUTHOR]

A lab-scale expanded granular sludge bed (EGSB) reactor was seeded with granular sludge and operated to investigate the influence of temperature decrease on both process performance and the microbial community structure of the granular sludge. Synthetic wastewater containing sucrose and volatile fatty acids was used as feed. The EGSB reactor was brought online at a starting temperature of 15°C and was reduced stepwise to a final temperature of 5°C. The reactor exhibited sufficient COD removal efficiency between 10°C and 15°C. However at 5°C serious deterioration of process performance was observed. The methane-producing activity of the retained sludge increased when it was compared to the activity of the seed sludge (day 0) during 10°C to 15°C operation. When hydrogen fed, sludge showed much higher methanogenic activity as compared with seed sludge activity at test temperatures of 15°C and 20°C on day 196 of reactor operation. At this time, proliferation of the genus Methanospirillum in the retained sludge was observed and a decrease in Methanobacterium species was also measured. Throughout the experiment, the genus Methanosaeta was detected in abundance and the community structure of the Domain Bacteria was stably maintained. The sugar-degrading acid-forming bacteria, Lactococcus and Anaerovibrio were detected in the retained sludge throughout the experiment as well and the propionate-degrading acetogen Syntrophobacter fumaroxidans was also detected, although its population size decreased at 5°C. [ABSTRACT FROM AUTHOR]

Microflora were investigated in traditional starter cultures for fermented milk, hurunge, which are used for fermented dairy products by nomadic families in the Inner Mongolia Autonomic Region, China. The acid-forming bacteria and yeast counts ranged from 1.8 × 105 to 5.3 × 108 c.f.u./g and from 6.1 × 105 to 3.2 × 106 c.f.u./g, respectively. Sixty-six strains of lactic acid bacteria and 30 strains of yeasts were isolated and identified from three hurunge samples collected from the nomadic families. Lactococcus raffinolactis was the most predominant lactococci isolated from these samples. The other lactococci were Lactococcus lactis ssp. lactis, Lactococcus lactis ssp. cremoris, and Leuconostoc mesenteroides ssp. cremoris. Two major lactobacilli strains, Lactobacillus plantarum and Lactobacillus casei, were identified. In addition, Lactobacillus kefiranofaciens, Lactobacillus acetotolerans, which grew in 11% acetic acid culture medium, and Lactobacillus homohiochii, which grew in the culture medium containing 16% ethanol, were also identified. The isolated yeast strains were identified as Candida kefyr, Saccharomyces cerevisiae, Kluyveromyces marxianus var. lactis, Candida krusei and Candida valida. [ABSTRACT FROM AUTHOR]

The effects of spore-bearing lactic acid-forming bacteria (Bacillus coagulans SANK 70258) on intestinal flora and decomposition products in the intestine, as well as on various dermal characteristics were determined in healthy humans and rats. Improvement of fecal shape, change of fecal color from dark brown to yellowish brown, decrease of fecal odor and fecal pH and an increase in defecation frequency in persons whose defecation frequency was relatively low were observed after administration. The number of intestinal bifidobacteria significantly (p <0.05) increased, whereas the number of intestinal Clostridium perfringens significantly (p <0.05) decreased after administration compared with the values before the intake. The concentrations of intestinal ammonia, indole and p-cresol decreased. The activities of β-glucuronidase and tryptophanase decreased significantly compared with the levels during the control period (p <0.05). The spore-bearing lactic acid-forming bacilli group was given B. coagulans SANK 70258, while kept on a basic diet adjusted to 60% protein. Protein was supplied by casein. After removing back hair, the rats were exposed to radiation of UV-B 0.5 MED once a day. Two weeks after the start of radiation, measurements were made for the number of exanthema (the number of flare and papula). The number of exanthema decreased as constipation alleviated as a result of the intake of B. coagulans SANK 70258. In experiment 2, improvement of fecal shape, change of fecal color from dark brown to yellowish brown, decrease of fecal odor, the fecal pH and increase in defecation frequency of persons whose frequency was relatively low were observed after administration. The number of intestinal bifidobacteria significantly (p <0.05) increased, whereas the number of intestinal C. perfringens significantly (p <0.05) decreased after administration compared with the values before the intake. The concentrations of intestinal ammonia, indole and p-cresol content decreased. The activity of β-glucuronidase and tryptophanase decreased significantly (p <0.05) compared with the levels during the control period. The number of comedones decreased as constipation was alleviated as a result of the intake of B. coagulans SANK 70258. These results indicate that the administration of B. coagulans SANK 70258 improves the intestinal environment, defecation frequency, fecal characteristics and dermal characteristics. [ABSTRACT FROM AUTHOR]

The production of rice-based beverages fermented by lactic acid bacteria (LAB) can increase the consumption of rice in the form of a dairy replacement. This study investigated volatile and nonvolatile components in rice fermented by 12 different LABs. Volatile compounds of fermented rice samples were analyzed using gas chromatography-mass spectrometry (GC-MS) combined with solid-phase microextraction (SPME), while nonvolatile compounds were determined using gas chromatography-time-of-flight/mass spectrometry (GC-TOF/MS) after derivatization. The 47 identified volatile compounds included acids, aldehydes, esters, furan derivatives, ketones, alcohols, benzene and benzene derivatives, hydrocarbons, and terpenes, while the 37 identified nonvolatile components included amino acids, organic acids, and carbohydrates. The profiles of volatile and nonvolatile components generally differed significantly between obligatorily homofermentative/facultatively heterofermentative LAB and obligatorily heterofermentative LAB. The rice sample fermented by Lactobacillus sakei (RTCL16) was clearly differentiated from the other samples on principal component analysis (PCA) plots. The results of PCA revealed that the rice samples fermented by LABs could be distinguished according to microbial strains. [ABSTRACT FROM AUTHOR]