Abstract:

Polyols 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.

Author affiliation: Ortiz, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina;

Author affiliation: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina;

Author affiliation: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina;

Author affiliation: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina;

Abstract:

Lactobacillus 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.

Author affiliation: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Author affiliation: Teran, Lucrecia Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Author affiliation: Bonacina, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Author affiliation: Saavedra, Maria Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Author affiliation: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Author affiliation: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Abstract:

Mannitol is a natural low-calorie sugar alcohol produced by certain (micro)organisms applicable in foods for diabetics due to its zero glycemic index. In this work, we evaluated mannitol production and yield by the fruit origin strain Fructobacillus tropaeoli CRL 2034 using response surface methodology with central composite design (CCD) as optimization strategy. The effect of the total saccharide (glucose + fructose, 1:2) content (TSC) in the medium (75, 100, 150, 200, and 225 g/l) and stirring (S; 50, 100, 200, 300 and 350 rpm) on mannitol production and yield by this strain was evaluated by using a 22 full-factorial CCD with 4 axial points (α = 1.5) and four replications of the center point, leading to 12 random experimental runs. Fermentations were carried out at 30 °C and pH 5.0 for 24 h. Minitab-15 software was used for experimental design and data analyses. The multiple response prediction analysis established 165 g/l of TSC and 200 rpm of S as optimal culture conditions to reach 85.03 g/l [95% CI (78.68, 91.39)] of mannitol and a yield of 82.02% [95% CI (71.98, 92.06)]. Finally, a validation experiment was conducted at the predicted optimum levels. The results obtained were 81.91 g/l of mannitol with a yield of 77.47% in outstanding agreement with the expected values. The mannitol 2-dehydrogenase enzyme activity was determined with 4.6–4.9 U/mg as the highest value found. To conclude, F. tropaeoli CRL 2034 produced high amounts of high-quality mannitol from fructose, being an excellent candidate for this polyol production.

Author affiliation: Ruiz Rodríguez, Luciana Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Author affiliation: Aller, Kadri. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Center for Food and Fermentation Technologies; Estonia

Author affiliation: Bru Chauve, Elena Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Author affiliation: De Vuyst, Luc. Vrije Universiteit Brussel; Bélgica

Author affiliation: Hebert, Elvira Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Author affiliation: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Abstract:

Lactic acid bacteria display a relatively simple and well-described metabolism where the sugar source is converted mainly to lactic acid. Here we will shortly describe metabolic engineering strategies on the level of sugar metabolism, that lead to either the efficient re-routing of the lactococcal sugar metabolism to nutritional end-products other than lactic acid such as L-alanine, several low-calorie sugars and oligosaccharides or to enhancement of sugar metabolism for complete removal of (undesirable) sugars from food materials. Moreover, we will review current metabolic engineering approaches that aim at increasing the flux through complex biosynthetic pathways, leading to the production of the B-vitamins folate and riboflavin. An overview of these metabolic engineering activities can be found on the website of the Nutra Cells 5th Framework EU-project (www.nutracells.com). Finally, the impact of the developments in the area of genomics and corresponding high-throughput technologies on nutraceutical production will be discussed.

Author affiliation: Hugenholtz, Jeroen. Wageningen Centre for Food Sciences; Países Bajos. NIZO Food Research; Países Bajos

Author affiliation: Sybesma, Wilbert. Wageningen Centre for Food Sciences; Países Bajos

Author affiliation: Groot, Masja Nierop. Wageningen Centre for Food Sciences; Países Bajos

Author affiliation: Wisselink, Wouter. Wageningen Centre for Food Sciences; Países Bajos. ATO-DLO; Países Bajos

Author affiliation: Ladero, Victor. Université Catholique de Louvain, Louvain-la-neuve, Bel; Bélgica

Author affiliation: Burgess, Kay. University College Cork; Irlanda

Author affiliation: van Sinderen, Douwe. University College Cork; Irlanda

Author affiliation: Piard, Jean-Christophe. Institut National de la Recherche Agronomique; Francia

Author affiliation: Eggink, Gerrit. Wageningen Centre for Food Sciences; Países Bajos. ATO-DLO; Países Bajos

Author affiliation: Smid, Eddy J.. NIZO Food Research; Países Bajos

Author affiliation: Savoy, Graciela. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Author affiliation: Sesma, Fernando Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Author affiliation: Jansen, Tanja. NIZO Food Research; Países Bajos

Author affiliation: Hols, Pascal. Université Catholique de Louvain; Bélgica

Author affiliation: Kleerebezem, Michiel. Wageningen Centre for Food Sciences; Países Bajos. NIZO Food Research; Países Bajos

Abstract:

Diclofenac potassium is an anti-inflammatory agent classified as a class II drug as per the biopharmaceutical classification system (BCS). The poor dissolution rate of water-insoluble drugs is still a major problem confronting the pharmaceutical industry. There are several techniques to enhance the dissolution of poorly soluble drugs. Methods available include salt formation, micronization and addition of solvent or surface active agents. The objective of the present work is to improve the dissolution profile of diclofenac potassium by formation of a physical mixture and a solid dispersion with mannitol. The solid dispersion was prepared by solvent method using ethanol/water. As diclofenac potassium melts with decomposition, the compatibility study with mannitol was done with the acid form by differential scanning calorimetry (DSC). The dissolution properties and physicochemical properties of diclofenac potassium:mannitol physical mixture and solid dispersion were investigated by Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and dissolution test. This study shows that the dissolution rate of diclofenac potassium can be enhanced considerably by formulating it with mannitol, as a physical mixture or as a solid dispersion although crystallinity was maintained.

Author affiliation: Han, Yong. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Laboratorio de Control de Calidad de Medicamentos; Argentina

Author affiliation: Faudone, Sonia Nerina. Provincia de Córdoba. Ministerio de Ciencia y Técnica. Centro de Excelencia en Productos y Procesos de Córdoba; Argentina

Author affiliation: Zitto, Gustavo. Provincia de Córdoba. Ministerio de Ciencia y Técnica. Centro de Excelencia en Productos y Procesos de Córdoba; Argentina

Author affiliation: Bonafede, Silvina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Laboratorio de Control de Calidad de Medicamentos; Argentina

Author affiliation: Rosasco, María Ana. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Laboratorio de Control de Calidad de Medicamentos; Argentina

Author affiliation: Segall, Adriana Ines. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Laboratorio de Control de Calidad de Medicamentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

The selective liquid-phase hydrogenation of d-fructose was studied on Cu-based catalyst, using an ethanol-water (70:30) mixture as solvent. The catalysts were prepared by three different methods: incipient wetness impregnation (Cu/SiO2-I and Cu/Al2O3-I), precipitation–deposition (Cu/SiO2-PD) and co-precipitation (CuMgAl and CuZnAl). After the thermal treatment, the samples were characterized by X-ray diffraction (XRD) and temperature-programmed reduction (TPR). Only a tenorite-like polycrystalline phase, formed by large CuO crystallites, was identified in Cu/SiO2-I, while none crystalline phase was observed in the case of Cu/SiO2-PD. Instead, a unique spinel-like phase was detected with Cu/Al2O3-I, CuMgAl and CuZnAl. Combining XRD and TPR results, we concluded that Cu2+ is highly dispersed in the Cu/SiO2-PD, Cu/Al2O3-I, CuMgAl and CuZnAl calcined precursors. As a consequence, after reduction in H2 flow, the metal dispersion and hydrogen chemisorption capacity of these four samples were one order higher than for Cu/SiO2-I. The catalytic tests showed that Cu/SiO2-PD was not only the most active but also the most selective and stable catalyst of these series: a D-fructose conversion of around 100% was reached after 6 h reaction, with a selectivity to d-mannitol of around 78–80%. These results show that selective hydrogenation of fructose to d-mannitol is favoured over metal Cu nanoparticles dispersed on the surface of a neutral support as SiO2. Additional catalytic tests, varying fructose initial concentration (0.028–0.220 M) and hydrogen pressure (20–40 bar), were carried out with Cu/SiO2-PD. A zero reaction order respect to D-fructose and a second reaction order respect to H2 were estimated. In addition, it was found that d-mannitol selectivity is not dependent on reactant initial concentration and hydrogen pressure.

Author affiliation: Zelin, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina

Author affiliation: Meyer, Camilo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina

Author affiliation: Regenhardt, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina

Author affiliation: Sebastian, V.. Universidad de Zaragoza; España. CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN); España

Author affiliation: Garetto, Teresita Francisca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina

Author affiliation: Marchi, Alberto Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina

Abstract:

Novel linear carbohydrate-derived [m,n]-polyurethanes are successfully prepared using D-mannitol as renewable and low cost starting material. The key comonomer, 1,6-di-O-phenylcarbonyl-2,3,4,5-tetra-O-methyl-D-mannitol is polymerized with a diamine synthesized from D-mannitol or with alkylenediamines. These polymerization reactions afford, respectively, a [6,6]-polyurethane entirely based on a carbohydrate derivative or [m,n]-polyurethanes constituted by a poly-O-methyl substituted unit alternating with a polymethylene chain. All these polymers are stereoregular, as result of the C2 axis of symmetry of mannitol. The optically active polyurethanes are characterized by standard methods (FTIR, RMN, GPC, TGA, and DSC). Thus, GPC analysis reveals weight-average molecular weights between 18,000 and 25,000 Da. Thermal studies (DSC) indicate that the polymers obtained are amorphous materials with Tg values dependent on the structure and chain length of the diamine constituent.

Author affiliation: Fidalgo, Daniela Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones En Hidratos de Carbono; Argentina

Author affiliation: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones En Hidratos de Carbono; Argentina

Author affiliation: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones En Hidratos de Carbono; Argentina

Abstract:

Novel linear carbohydrate-derived [m,n]-polyurethanes are successfully prepared using d-mannitol as renewable and low cost starting material. The key comonomer, 1,6-di-O-phenylcarbonyl-2,3,4,5-tetra-O-methyl-d-mannitol is polymerized with a diamine synthesized from d-mannitol or with alkylenediamines. These polymerization reactions afford, respectively, a [6,6]-polyurethane entirely based on a carbohydrate derivative or [m,n]-polyurethanes constituted by a poly-O-methyl substituted unit alternating with a polymethylene chain. All these polymers are stereoregular, as result of the C2 axis of symmetry of mannitol. The optically active polyurethanes are characterized by standard methods (FTIR, RMN, GPC, TGA, and DSC). Thus, GPC analysis reveals weight-average molecular weights between 18,000 and 25,000 Da. Thermal studies (DSC) indicate that the polymers obtained are amorphous materials with Tg values dependent on the structure and chain length of the diamine constituent.

Author affiliation: Fidalgo, Daniela Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentina

Author affiliation: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentina

Author affiliation: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentina