1,721,036 research outputs found
Nutraceutics and high value added metabolites produced by lactic acid bacteria
No full textDue to their broad metabolic versatility, lactic acid bacteria (LAB) have been extensively used in the food industry for the elaboration of diverse fermented foods and animal feeds. Beyond their classical application as food starter cultures, in recent years LAB have been employed as microbial cell factories for the production of interesting biochemicals such as food ingredients, commodity chemicals, and nutraceuticals. The profound study of LAB physiology together with the design of novel genetic tools for metabolic engineering studies gave rise to their use for novel biotechnological applications. The state-of-the-art of the biotechnological nutraceutic production by LAB, namely polyols (low-calorie sugars), polysaccharides, bioactive peptides, plant metabolites, and in much lesser extent vitamins (this topic will be covered in another chapter) by wild type or genetically modified LAB strains will be addressed in this chapter.Fil: Hebert, Elvira Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Savoy, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin
Low-calorie sugars produced by lactic acid bacteria
No full textMannitol, sorbitol, and erythritol are naturally occurring sugar alcohols. Mannitol is produced by bacteria, yeasts, fungi, algae, and several plants. This polyol might help these organisms to cope with different environmental stresses such as osmotic and oxidative stress. Sorbitol is produced by a variety of both plants and microorganisms. Erythritol production is usually associated with yeasts but has also been reported for some lactic acid bacteria (LAB). All these polyols — mannitol, sorbitol, and erythritol — display properties that are benefi cial to human health as they are non - metabolizable, insulin - independent sweeteners, or low - calorie sugars, which make them applicable in dietetic and diabetic food products. In addition, mannitol is used in the pharmaceutical industry as a powerful osmotic diuretic agent and as an osmotic agent for decreasing brain and cellular edema. Mannitol biosynthesis through bacterial fermentation has become an interesting alternative to existing chemical production. Chemical synthesis using nickel catalyst - assisted hydrogenation shows several economic disadvantages, such as high production costs and low product recovery. Furthermore, the capability of certain LAB, belonging to both homofermentative and heterofermentative species, to synthesize mannitol offers the possibility of in situ production in foods. For this reason, different fermentation technology - based strategies for improving mannitol production by LAB have been reported. To date, 93 – 97 mol% mannitol yields are reached using a bioprocess with a heterofermentative LAB strain. Moreover, metabolic engineering of food - grade lactate dehydrogenase - deficient mutants has been reported, in particular for sorbitol production by LAB. This chapter deals with the state of the art of sugar alcohol (mannitol, sorbitol, and erythritol) production by LAB as interesting low - calorie food ingredients. In addition, the strategies employed to increase the production and application of sugar alcohols in food and pharmaceutical products, or to design new functional foods naturally enriched in mannitol will be discussed.Fil: Vrancken, Gino. Vrije Unviversiteit Brussel; BélgicaFil: Rimaux, Tom. Vrije Unviversiteit Brussel; BélgicaFil: De Vuyst, Luc. Vrije Unviversiteit Brussel; BélgicaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin
Effect of medium composition and temperature and pH changes on exopolysaccharide yields and stability during Streptococcus thermophilus LY03 fermentations
Get PDFTo increase the exopolysaccharide (EPS) yields from Streptococcus thermophilus LY03 and to unravel the nature of the EPS degradation process, fermentation experiments were carried out with this strain in a customized MRS medium, using different additional carbohydrates or amino acids possibly related to growth and EPS production. No significant increase of the EPS yields or activities of the enzymes α-phosphoglucomutase, UDP-glucose pyrophosphorylase and UDP-galactose 4-epimerase that are correlated with EPS production, or of the activity of dTDP-glucose pyrophosphorylase involved in the rhamnose synthetic branch of EPS biosynthesis, was observed. The EPS monomer composition remained unchanged for all experiments. Fermentations with a sudden temperature increase or lowered pH were carried out as well to try to avoid EPS degradation upon prolonged fermentation. It was demonstrated that EPS degradation took place enzymatically. Incubations of purified high-molecular-mass EPS with cell-free culture supernatant or cell extracts showed its degradation by enzymes with an endo-activity. This glycohydrolytic activity probably encompasses several enzymes having a molecular mass lower than 50,000 and 10,000 Da, and seems to be rather stable at high temperature and low pH. These results contribute to a better understanding of the physiological and chemical factors influencing EPS production and degradation.Fil: Degeest, Bart. Vrije Universiteit Brussel; BélgicaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Vrije Universiteit Brussel; BélgicaFil: De Vuyst, Luc. Vrije Universiteit Brussel; Bélgic
Exopolysaccharide biosynthesis by Lactobacillus helveticus ATCC 15807
Get PDFExopolysaccharide (EPS) production and the activities of the enzymes involved in sugar nucleotide biosynthesis in Lactobacillus helveticus ATCC 15807 under controlled pH conditions were investigated. Batch fermentations using lactose as energy source showed higher EPS synthesis by L. helveticus ATCC 15807 at pH 4.5 with respect to pH 6.2, the enzyme α-phosphoglucomutase (α-PGM) being correlated with both total and specific EPS production. When glucose was used as carbon source instead of lactose, the lower EPS synthesis obtained was linked to a decrease in α-PGM and galactose 1-phosphate-uridyltransferase (GalT) activities, the reduction of the latter being more pronounced. Higher EPS production by L. helveticus ATCC 15807 at the acidic constant pH of 4.5 requires that both α-PGM and GalT activities are high. These enzymes are needed to synthesize UDP-glucose and UDP-galactose for supplying the corresponding monomers for EPS biosynthesis. Although differences are observed in EPS production by this strain regarding the energy source (lactose or glucose), the monomeric composition of the polymers produced is independent of the carbohydrate used. The obtained results contribute to a better understanding of the physiological factors that affect EPS biosynthesis by lactobacilli, which could help in the correct handling of the fermentation parameters within the fermented dairy industry.Fil: Torino, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Font, Graciela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin
Whey-derived valuable products obtained by microbial fermentation
Get PDFWhey, the main by-product of the cheese industry, is considered as an important pollutant due to its high chemical and biological oxygen demand. Whey, often considered as waste, has high nutritional value and can be used to obtain value-added products, although some of them need expensive enzymatic synthesis. An economical alternative to transform whey into valuable products is through bacterial or yeast fermentations and by accumulation during algae growth. Fermentative processes can be applied either to produce individual compounds or to formulate new foods and beverages. In the first case, a considerable amount of research has been directed to obtain biofuels able to replace those derived from petrol. In addition, the possibility of replacing petrol-derived plastics by biodegradable polymers synthesized during bacterial fermentation of whey has been sought. Further, the ability of different organisms to produce metabolites commonly used in the food and pharmaceutical industries (i.e., lactic acid, lactobionic acid, polysaccharides, etc.) using whey as growth substrate has been studied. On the other hand, new low-cost functional whey-based foods and beverages leveraging the high nutritional quality of whey have been formulated, highlighting the health-promoting effects of fermented whey-derived products. This review aims to gather the multiple uses of whey as sustainable raw material for the production of individual compounds, foods, and beverages by microbial fermentation. This is the first work to give an overview on the microbial transformation of whey as raw material into a large repertoire of industrially relevant foods and products.Fil: Pescuma, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); ArgentinaFil: Font, Graciela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); Argentin
Efficient mannitol production by wild-type Lactobacillus reuteri CRL 1101 is attained at constant pH using a simplified culture medium
Get PDFMannitol is a natural polyol with multiple industrial applications. In this work, mannitol production by Lactobacillus reuteri CRL 1101 was studied at free- and controlled-pH (6.0–4.8) fermentations using a simplified culture medium containing yeast and beef extracts and sugarcane molasses. The activity of mannitol 2-dehydrogenase (MDH), the enzyme responsible for mannitol synthesis, was determined. The effect of the initial biomass concentration was further studied. Mannitol production (41.5 ± 1.1 g/l), volumetric productivity (QMtl 1.73 ± 0.05 g/l h), and yield (YMtl 105 ± 11 %) were maximum at pH 5.0 after 24 h while the highest MDH activity (1.66 ± 0.09 U/mg protein) was obtained at pH 6.0. No correlation between mannitol production and MDH activity was observed when varying the culture pH. The increase (up to 2000-fold) in the initial biomass concentration did not improve mannitol formation after 24 h although a 2-fold higher amount was produced at 8 h using 1 or 2 g cell dry weight/l comparing to the control (0.001 g cell dry weight/l). Finally, mannitol isolation under optimum fermentation conditions was achieved. The mannitol production obtained in this study is the highest reported so far by a wild-type L. reuteri strain and, more interestingly, using a simplified culture medium.Fil: Ortiz, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin
Metabolomics as a tool for the comprehensive understanding of fermented and functional foods with lactic acid bacteria
Get PDFMetabolomics, also called metabonomics or metabolic profiling, deals with the simultaneous determination and quantitative analysis of intracellular metabolites or low-molecular-mass molecules. The metabolomics field, which has begun a little more than ten years ago thanks to the development of technologies such as nuclear magnetic resonance (NMR) and mass spectrometry (MS), has been successfully applied in different areas of food science. This review deals with the recent achievements of metabolomics in the comprehensive analysis of fermented foods predominated by lactic acid bacteria, the fermentative capacity of these microorganisms and the beneficial effects of functional foods and probiotics.Fil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); Argentina;Fil: Ortiz, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); Argentina;Fil: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); Argentina;Fil: de Vuyst, Luc. Vrije Unviversiteit Brussel. Faculty of Sciences and Bio-engineering Sciences; Bélgica;Fil: Pescuma, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); Argentina
Food-grade heteropolysaccharides: ongoing research and future trends of biopolymers from lactic acid bacteria
Get PDFExopolysaccharides (EPSs) produced by lactic acid bacteria (LAB) play a major role in the manufacturing of fermented foods, especially fermented dairy products. Although the presence of heteropolysaccharides (HePSs) seems not to confer any advantage to cell growth or survival, in situ production typically imparts a desirable viscous, sometimes ‘ropy’ texture to fermented foods and milk products. These food-grade biopolymers are economically important for the food industry. Current challenges are to improve the yield of HePSs from LAB and to produce HePSs with a particular functionality on the basis of a better understanding of their biosynthesis and the relationship between their structure and function.Fil: Font, Graciela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Torino, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: De Vuyst, Luc. Vrije Unviversiteit Brussel; BélgicaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin
Draft Genome Sequence of the Mannitol-Producing Strain Lactobacillus mucosae CRL573
Get PDFLactobacillus mucosae CRL573, isolated from child fecal samples, efficiently converts fructose and/or sucrose into the lowcalorie sugar mannitol when cultured in modified MRS medium at pH 5.0. Also, the strain is capable of producing bacteriocin. The draft genome sequence of this strain with potential industrial applications is presented here.Fil: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Teran, Lucrecia Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Bonacina, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Saavedra, Maria Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin
Biotechnological and in situ food production of polyols by lactic acid bacteria
Get PDFPolyols such as mannitol, erythritol, sorbitol, and xylitol are naturally found in fruits and vegetables and are produced by certain bacteria, fungi, yeasts, and algae. These sugar alcohols are widely used in food and pharmaceutical industries and in medicine because of their interesting physicochemical properties. In the food industry, polyols are employed as natural sweeteners applicable in light and diabetic food products. In the last decade, biotechnological production of polyols by lactic acid bacteria (LAB) has been investigated as an alternative to their current industrial production. While heterofermentative LAB may naturally produce mannitol and erythritol under certain culture conditions, sorbitol and xylitol have been only synthesized through metabolic engineering processes. This review deals with the spontaneous formation of mannitol and erythritol in fermented foods and their biotechnological production by heterofermentative LAB and briefly presented the metabolic engineering processes applied for polyol formation.Fil: Ortiz, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); ArgentinaFil: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); ArgentinaFil: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentin
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