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Molecules (Basel, Switzerland) Nov 2019CCK940, which exhibits glycosyltransferase activity, produces oligosaccharides using sucrose and maltose as donor and receptor molecules, respectively. The...
CCK940, which exhibits glycosyltransferase activity, produces oligosaccharides using sucrose and maltose as donor and receptor molecules, respectively. The oligosaccharides produced were purified by Bio-gel P2 chromatography and the purified oligosaccharides (CCK-oligosaccharides) consisted of only glucose. H-NMR analysis revealed that the CCK-oligosaccharides were composed of 77.6% α-1,6 and 22.4% α-1,4 glycosidic linkages, and the molecular weight of the CCK-oligosaccharides was found to be 9.42 × 10 Da. To determine the prebiotic effect of the CCK-oligosaccharides, various carbon sources were added in modified media. Growth of six probiotic strains, , , , , , and , was better when the CCK-oligosaccharides were used as the sole carbon source compared to fructo-oligosaccharides, which are widely used as prebiotics. These results showed that the CCK-oligosaccharides produced from CCK940 could serve as good candidates for novel prebiotics.
Topics: Bifidobacterium; Fermentation; Lactobacillus; Leuconostoc; Maltose; Oligosaccharides; Prebiotics; Probiotics; Sucrose
PubMed: 31694205
DOI: 10.3390/molecules24213998 -
Microbial Cell Factories Jan 2021Lactic acid bacteria can synthesize dextran and oligosaccharides with different functionality, depending on the strain and fermentation conditions. As natural...
BACKGROUND
Lactic acid bacteria can synthesize dextran and oligosaccharides with different functionality, depending on the strain and fermentation conditions. As natural structure-forming agent, dextran has proven useful as food additive, improving the properties of several raw materials with poor technological quality, such as cereal by-products, fiber-and protein-rich matrices, enabling their use in food applications. In this study, we assessed dextran biosynthesis in situ during fermentation of brewers´ spent grain (BSG), the main by-product of beer brewing industry, with Leuconostoc pseudomesenteroides DSM20193 and Weissella confusa A16. The starters performance and the primary metabolites formed during 24 h of fermentation with and without 4% sucrose (w/w) were followed.
RESULTS
The starters showed similar growth and acidification kinetics, but different sugar utilization, especially in presence of sucrose. Viscosity increase in fermented BSG containing sucrose occurred first after 10 h, and it kept increasing until 24 h concomitantly with dextran formation. Dextran content after 24 h was approximately 1% on the total weight of the BSG. Oligosaccharides with different degree of polymerization were formed together with dextran from 10 to 24 h. Three dextransucrase genes were identified in L. pseudomesenteroides DSM20193, one of which was significantly upregulated and remained active throughout the fermentation time. One dextransucrase gene was identified in W. confusa A16 also showing a typical induction profile, with highest upregulation at 10 h.
CONCLUSIONS
Selected lactic acid bacteria starters produced significant amount of dextran in brewers' spent grain while forming oligosaccharides with different degree of polymerization. Putative dextransucrase genes identified in the starters showed a typical induction profile. Formation of dextran and oligosaccharides in BSG during lactic acid bacteria fermentation can be tailored to achieve specific technological properties of this raw material, contributing to its reintegration into the food chain.
Topics: Beer; Dextrans; Edible Grain; Fermentation; Gene Expression Regulation, Enzymologic; Glucosyltransferases; Hydrogen-Ion Concentration; Lactobacillales; Leuconostoc; Mannitol; Oligosaccharides; Polysaccharides; Sucrose; Viscosity; Weissella
PubMed: 33482833
DOI: 10.1186/s12934-021-01515-4 -
International Journal of Food... Aug 2018Fresh cut iceberg lettuce spoilage was studied considering the microbial and biochemical activity, the formation of volatile organic compounds (VOC) and consumer...
Fresh cut iceberg lettuce spoilage was studied considering the microbial and biochemical activity, the formation of volatile organic compounds (VOC) and consumer acceptability. Lettuce was packaged under three different packaging conditions and stored at 4 °C for 10 days: anaerobic packaging (ANAER), equilibrium modified atmosphere packaging with 3% O (EMAP) and perforated packages (AIR). Results indicated a clear distinction between packaging conditions. EMAP and AIR resulted in a short shelf life (≤5.6 days) which was limited due to browning, leading to consumer rejection as assessed via the Weibull hazard analysis method, while no off-odors were detected. Culture- independent 16 s rRNA gene amplicon sequencing revealed Pseudomonas spp. as the dominating species. In contrast, under ANAER conditions, lactic acid bacteria dominated with genera of Leuconostoc spp. and Lactococcus spp. proliferating, while also oligotypes of Pseudomonas spp. were found. Spoilage under ANAER occurred after 6.6 days and it was related to strong fermentative-like off-odors that were present by the end of storage. As revealed by selective ion flow tube mass spectrometry (SIFT-MS), these odors were associated with several VOCs such as: ethanol, 3-methyl-1-butanol, 2,3-butanediol, (Z)-3-hexen-1-ol, hexanal, acetic acid, ethyl acetate and dimethyl sulfide. Panelists rejected the iceberg lettuce due to the formation of off-odors while the overall appearance remained good throughout the study. Hence a sensor based technology incorporated in the packaging, detecting VOCs and in particular ethanol as dominant compound, could serve as a spoilage indicator for ANAER packed lettuce, which proved to have the longest shelf life.
Topics: Anaerobiosis; Colony Count, Microbial; Food Microbiology; Food Packaging; Food Preservation; Lactococcus; Lactuca; Leuconostoc; Odorants; Oxygen; Pseudomonas; Volatile Organic Compounds
PubMed: 29715602
DOI: 10.1016/j.ijfoodmicro.2018.04.034 -
Journal of Bacteriology Feb 1998A citrate lyase (EC 4.1.3.6) was purified 25-fold from Leuconostoc mesenteroides and was shown to contain three subunits. The first 42 amino acids of the beta subunit...
A citrate lyase (EC 4.1.3.6) was purified 25-fold from Leuconostoc mesenteroides and was shown to contain three subunits. The first 42 amino acids of the beta subunit were identified, as well as an internal peptide sequence spanning some 20 amino acids into the alpha subunit. Using degenerated primers from these sequences, we amplified a 1.2-kb DNA fragment by PCR from Leuconostoc mesenteroides subsp. cremoris. This fragment was used as a probe for screening a Leuconostoc genomic bank to identify the structural genes. The 2.7-kb gene cluster encoding citrate lyase of L. mesenteroides is organized in three open reading frames, citD, citE, and citF, encoding, respectively, the three citrate lyase subunits gamma (acyl carrier protein [ACP]), beta (citryl-S-ACP lyase; EC 4.1.3.34), and alpha (citrate:acetyl-ACP transferase; EC 2.8.3.10). The gene (citC) encoding the citrate lyase ligase (EC 6.2.1.22) was localized in the region upstream of citD. Protein comparisons show similarities with the citrate lyase ligase and citrate lyase of Klebsiella pneumoniae and Haemophilus influenzae. Downstream of the citrate lyase cluster, a 1.4-kb open reading frame encoding a 52-kDa protein was found. The deduced protein is similar to CitG of the other bacteria, and its function remains unknown. Expression of the citCDEFG gene cluster in Escherichia coli led to the detection of a citrate lyase activity only in the presence of acetyl coenzyme A, which is a structural analog of the prosthetic group. This shows that the acetyl-ACP group of the citrate lyase form in E. coli is not complete or not linked to the protein.
Topics: Acyl Carrier Protein; Amino Acid Sequence; Bacterial Proteins; Base Sequence; Carbon-Sulfur Ligases; Cloning, Molecular; Coenzyme A-Transferases; DNA, Bacterial; Escherichia coli; Gene Expression; Genes, Bacterial; Leuconostoc; Molecular Sequence Data; Multienzyme Complexes; Multigene Family; Oxo-Acid-Lyases; Sequence Analysis, DNA; Sequence Homology, Amino Acid
PubMed: 9457870
DOI: 10.1128/JB.180.3.647-654.1998 -
Scientific Reports Apr 2021Nicotinamide mononucleotide (NMN), an intermediate in nicotinamide adenine dinucleotide biosynthesis, is recently attracting much attention for its pharmacological and...
Nicotinamide mononucleotide (NMN), an intermediate in nicotinamide adenine dinucleotide biosynthesis, is recently attracting much attention for its pharmacological and anti-aging efficacies. However, current commercial products containing NMN are very high-priced because efficient and facile methods for industrial NMN production are limited. In this study, aiming for its nutraceutical application, we attempted to screen lactic acid bacteria for intracellular and/or extracellular NMN production. Using a bioassay system with an auxotrophic yeast that requires nicotinamide riboside (NR; dephosphorylated NMN), three candidates were obtained from a library of 174 strains of facultative anaerobic lactic acid bacteria. All three candidates belonged to the genus Fructobacillus and produced NR in the culture media (0.8-1.5 mg/l). Lactic acid bacteria of the genus Fructobacillus are known to use D-fructose as an electron acceptor in anaerobic lactic acid fermentation; addition of D-fructose to the medium caused intracellular accumulation of NMN and NR, but no extracellular production of these compounds was observed. Draft genome sequencing for one of the candidates suggested that nicotinamide phosphoribosyltransferase, which exists commonly in mammals but is less reported in microorganisms, is a key enzyme for NMN and NR production in the fructophilic bacteria.
Topics: Escherichia coli; Fructose; Lactobacillales; Leuconostoc; Niacinamide; Nicotinamide Mononucleotide; Nicotinamide Phosphoribosyltransferase; Pyridinium Compounds
PubMed: 33828213
DOI: 10.1038/s41598-021-87361-1 -
Applied and Environmental Microbiology Dec 2015A levan-producing strain, BD1707, was isolated from Tibetan kefir and identified as Leuconostoc citreum. The effects of carbon sources on the growth of L. citreum BD1707...
A levan-producing strain, BD1707, was isolated from Tibetan kefir and identified as Leuconostoc citreum. The effects of carbon sources on the growth of L. citreum BD1707 and levan production in tomato juice were measured. The changes in pH, viable cell count, sugar content, and levan yield in the cultured tomato juice supplemented with 15% (wt/vol) sucrose were also assayed. L. citreum BD1707 could synthesize more than 28 g/liter of levan in the tomato juice-sucrose medium when cultured at 30°C for 96 h. Based on the monosaccharide composition, molecular mass distribution, Fourier transform infrared (FTIR) spectra, and nuclear magnetic resonance (NMR) spectra, the levan synthesized by L. citreum BD1707 was composed of a linear backbone consisting of consecutive β-(2→6) linked d-fructofuranosyl units, with an estimated average molecular mass of 4.3 × 10(6) Da.
Topics: Culture Media; Food Microbiology; Fructans; Hydrogen-Ion Concentration; Leuconostoc; Solanum lycopersicum; Magnetic Resonance Spectroscopy; Microbial Viability; Molecular Weight; Spectroscopy, Fourier Transform Infrared; Sucrose; Temperature; Tibet; Time Factors
PubMed: 26682858
DOI: 10.1128/AEM.02944-15 -
Applied and Environmental Microbiology Jun 2018Spontaneous vegetable fermentations, with their rich flavors and postulated health benefits, are regaining popularity. However, their microbiology is still poorly...
Spontaneous vegetable fermentations, with their rich flavors and postulated health benefits, are regaining popularity. However, their microbiology is still poorly understood, therefore raising concerns about food safety. In addition, such spontaneous fermentations form interesting cases of man-made microbial ecosystems. Here, samples from 38 carrot juice fermentations were collected through a citizen science initiative, in addition to three laboratory fermentations. Culturing showed that were outcompeted by lactic acid bacteria (LAB) between 3 and 13 days of fermentation. Metabolite-target analysis showed that lactic acid and mannitol were highly produced, as well as the biogenic amine cadaverine. High-throughput 16S rRNA gene sequencing revealed that mainly species of and (as identified by 8 and 20 amplicon sequence variants [ASVs], respectively) mediated the fermentations in subsequent order. The analyses at the DNA level still detected a high number of , but their relative abundance was low when RNA-based sequencing was performed to detect presumptive metabolically active bacterial cells. In addition, this method greatly reduced host read contamination. Phylogenetic placement indicated a high LAB diversity, with ASVs from nine different phylogenetic groups of the genus complex. However, fermentation experiments with isolates showed that only strains belonging to the most prevalent phylogenetic groups preserved the fermentation dynamics. The carrot juice fermentation thus forms a robust man-made microbial ecosystem suitable for studies on LAB diversity and niche specificity. The usage of fermented food products by professional chefs is steadily growing worldwide. Meanwhile, this interest has also increased at the household level. However, many of these artisanal food products remain understudied. Here, an extensive microbial analysis was performed of spontaneous fermented carrot juices which are used as nonalcoholic alternatives for wine in a Belgian Michelin star restaurant. Samples were collected through an active citizen science approach with 38 participants, in addition to three laboratory fermentations. Identification of the main microbial players revealed that mainly species of and mediated the fermentations in subsequent order. In addition, a high diversity of lactic acid bacteria was found; however, fermentation experiments with isolates showed that only strains belonging to the most prevalent lactic acid bacteria preserved the fermentation dynamics. Finally, this study showed that the usage of RNA-based 16S rRNA amplicon sequencing greatly reduces host read contamination.
Topics: Antibiosis; Biodiversity; Colony Count, Microbial; Daucus carota; Enterobacteriaceae; Fermentation; Food Microbiology; Fruit and Vegetable Juices; Lactobacillales; Leuconostoc; Phylogeny; RNA, Ribosomal, 16S
PubMed: 29654180
DOI: 10.1128/AEM.00134-18 -
International Journal of Food... Mar 2021The microbial community of ungerminated and germinated barley grains from three different cultivars grown at four different locations in Norway was investigated by...
The microbial community of ungerminated and germinated barley grains from three different cultivars grown at four different locations in Norway was investigated by culture dependent and culture independent methods. Lactic acid bacteria (LAB) was focused in this study and was isolated from germinated barley. The number of LAB ranged between 2.8 and 4.6 log cfu/g in ungerminated grains and between 4.9 and 6.3 log cfu/g in germinated grains. In total 66 out of 190 isolates were Gram+, catalase-negative and presumptive LAB. The LAB isolates were by 16S rRNA sequencing identified to be Carnobacterium maltaromaticum (6), Lactococcus lactis (2), Enterococcus sp. (1) and Leuconostoc sp. (57). Germination significantly influenced the bacterial composition. Regarding the different cultivars and growth places no significant difference in bacterial composition was seen. The most abundant bacterial genus was Pantoea (18.5% of the total sequences), followed by Rhizobium (10.1%) and Sphingomonas (9.9%). Fungal composition was significantly influenced by the germination process and the cultivation place, but no significant difference in fungal composition was detected between the 3 cultivars. The most abundant fungal genera were Cryptococcus (43.8% of all the sequences), Cladosporium (8.2%), Pyrenophora (7.4%) and Vagicola (6.3%). This study revealed knowledge of barley grain associated microbes of Norwegian barley that can be useful to control the malt quality. Germination affected both bacterial and fungal microbiota composition. No difference in bacterial microbiota composition was seen regarding cultivars and cultivation place, however, the fungal microbiota composition was significantly influenced by the cultivation place. Differences in fungal community of ungerminated and germinated barley samples of different geographical locations were more pronounced than differences in bacterial communities.
Topics: Carnobacterium; Enterococcus; Fungi; Germination; Hordeum; Lactococcus lactis; Leuconostoc; Microbiota; Norway; RNA, Ribosomal, 16S
PubMed: 33508581
DOI: 10.1016/j.ijfoodmicro.2021.109059 -
Carbohydrate Polymers Jan 2024Several lactic acid bacteria are able to produce water-soluble and water-insoluble homoexopolysaccharides (HoEPS) from sucrose. In this study, structures of all HoEPS...
Several lactic acid bacteria are able to produce water-soluble and water-insoluble homoexopolysaccharides (HoEPS) from sucrose. In this study, structures of all HoEPS which were fermentatively produced by Leuconostoc mesenteroides subsp. dextranicum NRRL B-1121 and B-1144, Leuconostoc mesenteroides subsp. mesenteroides NRRL B-1149, B-1438 and B-1118, Leuconostoc suionicum DSM 20241, and Liquorilactobacillus satsumensis DSM 16230 were systematically analyzed. Monosaccharide analysis, methylation analysis, NMR spectroscopy, size-exclusion chromatography, and different enzymatic fingerprinting methods were used to obtain detailed structural information. All strains produced water-soluble dextrans and/or levans as well as water-insoluble glucans. Levans showed different degrees of branching and high molecular weights, whereas dextrans had comparable structures and broader size distributions. Fine structures of water-soluble HoEPS were analyzed after endo-dextranase and endo-levanase hydrolysis. Water-insoluble glucans were composed of different portions of 1,3-linkages (5 to 40 %). Hydrolysis with endo-dextranase and endo-mutanase yielded further information on block sizes and varying fine structures. Overall, clear differences between HoEPS yields and structures were observed.
Topics: Dextrans; Lactobacillales; Dextranase; Water; Leuconostoc; Glucans; Fructans
PubMed: 37940249
DOI: 10.1016/j.carbpol.2023.121417 -
International Journal of Molecular... Sep 2020DRP105 isolated from Chinese sauerkraut juice is an intensive producer of dextran. We report the complete genome sequence of DRP105. This strain contains a...
DRP105 isolated from Chinese sauerkraut juice is an intensive producer of dextran. We report the complete genome sequence of DRP105. This strain contains a dextransucrase gene () involved in the production of dextran, possibly composed of glucose monomers. To explore the dextran synthesis mechanism of DRP105, we constructed a -deficient strain derived from DRP105 using the Cre-loxP recombination system. The secondary structure prediction results showed that DRP105 dextransucrase (Dsr) was coded by and contained 17.07% -helices, 29.55% -sheets, 10.18% -turns, and 43.20% random coils. We also analyzed the dextran yield, monosaccharide change, organic acid, and amino-acid content of DRP105 and DRP105-. The result showed that the lack of changed the DRP105 sugar metabolism pathway, which in turn affected the production of metabolites.
Topics: Carbohydrate Metabolism; Genome, Bacterial; Glucosyltransferases; Leuconostoc mesenteroides
PubMed: 32916950
DOI: 10.3390/ijms21186596