scholarly journals Metabolism of Fructophilic Lactic Acid Bacteria Isolated from the Apis mellifera L. Bee Gut: Phenolic Acids as External Electron Acceptors

2016 ◽  
Vol 82 (23) ◽  
pp. 6899-6911 ◽  
Author(s):  
Pasquale Filannino ◽  
Raffaella Di Cagno ◽  
Rocco Addante ◽  
Erica Pontonio ◽  
Marco Gobbetti

ABSTRACTFructophilic lactic acid bacteria (FLAB) are strongly associated with the gastrointestinal tracts (GITs) ofApis melliferaL. worker bees due to the consumption of fructose as a major carbohydrate. Seventy-seven presumptive lactic acid bacteria (LAB) were isolated from GITs of healthyA. melliferaL. adults, which were collected from 5 different geographical locations of the Apulia region of Italy. Almost all of the isolates showed fructophilic tendencies: these isolates were identified asLactobacillus kunkeei(69%) orFructobacillus fructosus(31%). A high-throughput phenotypic microarray targeting 190 carbon sources was used to determine that 83 compounds were differentially consumed. Phenotyping grouped the strains into two clusters, reflecting growth performance. The utilization of phenolic acids, such asp-coumaric, caffeic, syringic, or gallic acids, as electron acceptors was investigated in fructose-based medium. Almost all FLAB strains showed tolerance to high phenolic acid concentrations.p-Coumaric acid and caffeic acid were consumed by all FLAB strains through reductases or decarboxylases. Syringic and gallic acids were partially metabolized. The data collected suggest that FLAB require external electron acceptors to regenerate NADH. The use of phenolic acids as external electron acceptors by the 4 FLAB showing the highest phenolic acid reductase activity was investigated in glucose-based medium supplemented withp-coumaric acid. Metabolic responses observed through a phenotypic microarray suggested that FLAB may usep-coumaric acid as an external electron acceptor, enhancing glucose dissimilation but less efficiently than other external acceptors such as fructose or pyruvic acid.IMPORTANCEFructophilic lactic acid bacteria (FLAB) remain to be fully explored. This study intends to link unique biochemical features of FLAB with their habitat. The quite unique FLAB phenome within the group lactic acid bacteria (LAB) may have practical relevance in food fermentations. The FLAB phenome may have implications for the levels of hexose metabolism products in fermented foods, as well as food probiotication. Due to the harsh conditions of honeybees' GITs, these bacteria had to develop specific physiological and biochemical characteristics, such as tolerance to phenolic acids. The screening of FLAB strains based on metabolic pathways involving phenolic acids may allow the selection of starter cultures with both technological and functional beneficial attributes. Bioconversion of phenolic compounds may contribute to the aroma attributes and biofunctionality of fermented foods. Thus, the selection of FLAB strains as starter cultures with specific enzymatic activities involving phenolic acids may have a promising role in food fermentations.

2013 ◽  
Vol 79 (18) ◽  
pp. 5670-5681 ◽  
Author(s):  
Philipp Adler ◽  
Christoph Josef Bolten ◽  
Katrin Dohnt ◽  
Carl Erik Hansen ◽  
Christoph Wittmann

ABSTRACTIn the present work, simulated cocoa fermentation was investigated at the level of metabolic pathway fluxes (fluxome) of lactic acid bacteria (LAB), which are typically found in the microbial consortium known to convert nutrients from the cocoa pulp into organic acids. A comprehensive13C labeling approach allowed to quantify carbon fluxes during simulated cocoa fermentation by (i) parallel13C studies with [13C6]glucose, [1,2-13C2]glucose, and [13C6]fructose, respectively, (ii) gas chromatography-mass spectrometry (GC/MS) analysis of secreted acetate and lactate, (iii) stoichiometric profiling, and (iv) isotopomer modeling for flux calculation. The study of several strains ofL. fermentumandL. plantarumrevealed major differences in their fluxes. TheL. fermentumstrains channeled only a small amount (4 to 6%) of fructose into central metabolism, i.e., the phosphoketolase pathway, whereas onlyL. fermentumNCC 575 used fructose to form mannitol. In contrast,L. plantarumstrains exhibited a high glycolytic flux. All strains differed in acetate flux, which originated from fractions of citrate (25 to 80%) and corresponding amounts of glucose and fructose. Subsequent, metafluxome studies with consortia of differentL. fermentumandL. plantarumstrains indicated a dominant (96%) contribution ofL. fermentumNCC 575 to the overall flux in the microbial community, a scenario that was not observed for the other strains. This highlights the idea that individual LAB strains vary in their metabolic contribution to the overall fermentation process and opens up new routes toward streamlined starter cultures.L. fermentumNCC 575 might be one candidate due to its superior performance in flux activity.


2018 ◽  
Vol 84 (17) ◽  
Author(s):  
Laura Santamaría ◽  
Inés Reverón ◽  
Félix López de Felipe ◽  
Blanca de las Rivas ◽  
Rosario Muñoz

ABSTRACTEthylphenols are strong odorants produced by microbial activity that are described as off flavors in several foods.Lactobacillus plantarumis a lactic acid bacterial species able to produce ethylphenols by the reduction of vinylphenols during the metabolism of hydroxycinnamic acids. However, the reductase involved has not been yet uncovered. In this study, the involvement in vinylphenol reduction of a gene encoding a putative reductase (lp_3125) was confirmed by the absence of reduction activity in the Δlp_3125knockout mutant. The protein encoded bylp_3125, VprA, was recombinantly produced inEscherichia coli. VprA was assayed against vinylphenols (4-vinylphenol, 4-vinylcatechol, and 4-vinylguaiacol), and all were reduced to their corresponding ethylphenols (4-ethylphenol, 4-ethylcatechol, and 4-ethylguaiacol). PCR and high-performance liquid chromatography (HPLC) detection methods revealed that the VprA reductase is not widely distributed among the lactic acid bacteria studied and that only the bacteria possessing thevprAgene were able to produce ethylphenol from vinylphenol. However, all the species belonging to theL. plantarumgroup were ethylphenol producers. The identification of theL. plantarumVprA protein involved in hydroxycinnamate degradation completes the route of degradation of these compounds in lactic acid bacteria.IMPORTANCEThe presence of volatile phenols is considered a major organoleptic defect of several fermented alcoholic beverages. The biosynthesis of these compounds has been mainly associated withBrettanomyces/Dekkerayeasts. However, the potential importance of lactic acid bacteria in volatile phenol spoilage is emphasized by reports describing a faster ethylphenol production by these bacteria than by yeasts. The genetic identification of the bacterial vinylphenol reductase involved in volatile phenol production provides new insights into the role of lactic acid bacteria in the production of these off flavors. The development of a molecular method for the detection of ethylphenol-producing bacteria could be helpful to design strategies to reduce the bacterial production of vinylphenols in fermented foods.


2020 ◽  
Vol 8 (8) ◽  
pp. 1176 ◽  
Author(s):  
Tolulope Ashaolu ◽  
Anna Reale

Lactic acid fermentation is one of the oldest methods used worldwide to preserve cereals and vegetables. Europe and Asia have long and huge traditions in the manufacturing of lactic acid bacteria (LAB)-fermented foods. They have different cultures, religions and ethnicities with the available resources that strongly influence their food habits. Many differences and similarities exist with respect to raw substrates, products and microbes involved in the manufacture of fermented products. Many of them are produced on industrial scale with starter cultures, while others rely on spontaneous fermentation, produced homemade or in traditional events. In Europe, common LAB-fermented products made from cereals include traditional breads, leavened sweet doughs, and low and non-alcoholic cereal-based beverages, whereas among vegetable ones prevail sauerkraut, cucumber pickles and olives. In Asia, the prevailing LAB-fermented cereals include acid-leavened steamed breads or pancakes from rice and wheat, whereas LAB-fermented vegetables are more multifarious, such as kimchi, sinki, khalpi, dakguadong, jiang-gua, soidon and sauerkraut. Here, an overview of the main Euro-Asiatic LAB-fermented cereals and vegetables was proposed, underlining the relevance of fermentation as a tool for improving cereals and vegetables, and highlighting some differences and similarities among the Euro-Asiatic products. The study culminated in “omics”-based and future-oriented studies of the fermented products.


2020 ◽  
Vol 74 (5) ◽  
pp. 391-397
Author(s):  
Janine Anderegg ◽  
Florentin Constancias ◽  
Leo Meile

Tyramine is a health-adverse biogenic amine, which can accumulate in fermented foods like cheese by decarboxylation of the free amino acid tyrosine by either starter cultures or resident microbes such as lactic acid bacteria including Enterococcus spp., respectively. Our study aimed to show the effect of sodium chloride concentrations on tyramine production as well as to characterise bacterial strains as anti-tyramine biocontrol agents in a 2 mL micro-cheese fermentation model. The effect of sodium chloride on tyramine production was assayed with tyramine producing strains from eight different species or subspecies. Generally, an increase in sodium chloride concentration enhanced tyramine production, e.g. from 0% to 1.5% of sodium chloride resulted in an increase of tyramine of 870% with a Staphylococcus xylosus strain. In the biocontrol screening among lactic acid bacteria, a Lactobacillus plantarum JA-1199 strain was screened that could consume in successful competition with other resident bacteria tyrosine in the micro-cheese model as a source of energy gain. Thereby tyramine accumulation was reduced between 4% to 99%. The results of this study disclose a feasible strategy for decreasing tyramine concentration and increasing the safety level of fermented food. It is an example of development and application of bacterial isolates as starter or protective cultures in food, a biocontrol topic, which Oreste Ghisalba – in his project evaluation function of SNF and later on CTI – was promoting with great emphasis in our ETH Food Biotechnology research group.


Foods ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 17 ◽  
Author(s):  
Federica Barbieri ◽  
Chiara Montanari ◽  
Fausto Gardini ◽  
Giulia Tabanelli

Lactic acid bacteria (LAB) are considered as the main biogenic amine (BA) producers in fermented foods. These compounds derive from amino acid decarboxylation through microbial activities and can cause toxic effects on humans, with symptoms (headache, heart palpitations, vomiting, diarrhea) depending also on individual sensitivity. Many studies have focused on the aminobiogenic potential of LAB associated with fermented foods, taking into consideration the conditions affecting BA accumulation and enzymes/genes involved in the biosynthetic mechanisms. This review describes in detail the different LAB (used as starter cultures to improve technological and sensorial properties, as well as those naturally occurring during ripening or in spontaneous fermentations) able to produce BAs in model or in real systems. The groups considered were enterococci, lactobacilli, streptococci, lactococci, pediococci, oenococci and, as minor producers, LAB belonging to Leuconostoc and Weissella genus. A deeper knowledge of this issue is important because decarboxylase activities are often related to strains rather than to species or genera. Moreover, this information can help to improve the selection of strains for further applications as starter or bioprotective cultures, in order to obtain high quality foods with reduced BA content.


2018 ◽  
pp. 77-80 ◽  
Author(s):  
N. E. Posokina ◽  
O. Yu. Lyalina ◽  
A. I. Zakharova ◽  
E. S. Shishlova ◽  
V. I. Tereshonok

Along with heat treatment, Smoking and drying in the sun, one of the oldest ways to preserve food is fermentation (fermentation). Fermented foods appeared long before people learned about the existence of microorganisms, and entered the traditional diet of almost all cultures. Currently, the production of salted, fermented and wetted products is an important segment of the food industry. The rate of reproduction of microorganisms in foods is affected by several factors including properties of the products (nutrient content, pH value, oxidation-reduction (redox) potential, water activity, etc.) and external factors, including storage conditions, such as temperature and relative humidity. Preservation of food products is usually based on the destruction of microorganisms or control of their reproduction and the overall composition of the microbiota. Reducing the rate or preventing microbiological spoilage of food is based on four main principles: minimization of product contamination by microorganisms; suppression of growth and reproduction of micro-organisms-contaminants; destruction of micro-organisms-contaminants; removal of micro-organisms-contaminants. Fermentation is based on a combination of the first three principles and is achieved by creating conditions for the growth of specific microorganisms that can give food the desired taste, aroma, texture and appearance. This review is devoted to the scientific aspects of vegetable fermentation, including the use of bacterial starter cultures. The characteristics of lactic acid microorganisms are given, the basic principles and advantages of the process of fermentation of vegetables and the biochemical processes taking place at the same time are given and described, the advantages of the use of bacterial starter cultures (strains of lactic acid microorganisms) for the purpose of improving the quality of the finished product are described.


Author(s):  
Nair Temis Olguin ◽  
Lucrecia Delfederico ◽  
Liliana Semorile

Some phenolic acids can either inhibit or stimulate the growth of Oenococcus oeni and other lactic acid bacteria (LAB) in wine. It has been observed that some LAB metabolism could have an influence on wine colour. In this article, some of the relationships between LAB, malolactic fermentation (MLF) and phenolic compounds are summarised; these relationships are important for the selection of LAB to make starter cultures and are of interest for wineries in terms of its effect on wine colour.


Biomolecules ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 768 ◽  
Author(s):  
Dalin Ly ◽  
Sigrid Mayrhofer ◽  
I. Agung Yogeswara ◽  
Thu-Ha Nguyen ◽  
Konrad Domig

Screening for various types of lactic acid bacteria (LAB) that form the biological agent γ-amino-butyric acid (GABA) is important to produce different kinds of GABA-containing fermented foods. So far, no GABA-producing LAB have been reported from Cambodian fermented foods. Most small-scale fermentations and even some industrial processes in this country still rely on indigenous LAB. The application of GABA-producing autochthonous starters would allow the production of Cambodian fermented foods with an additional nutritional value that meet the population’s dietary habits and that are also more attractive for the international food market. Matrix-assisted laser desorption/ionizing time-of-flight mass spectrometry (MALDI-TOF MS) and partial 16S rDNA sequencing were used to identify 68 LAB isolates from Cambodian fermented foods. These isolates were classified and grouped with (GTG)5 rep-PCR, resulting in 50 strains. Subsequently, all strains were investigated for their ability to produce GABA by thin layer chromatography. GABA-positive strains were further analyzed by the GABase assay. Of the six GABA-positive LAB strains—one Lactobacillus futsaii, two Lactobacillus namurensis, and three Lactobacillus plantarum strains—two Lactobacillus plantarum strains produced high amounts of GABA (20.34 mM, 16.47 mM). These strains should be further investigated for their potential application as GABA-producing starter cultures in the food applications.


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