The effect of hexose ratios on metabolite production in Saccharomyces cerevisiae strains obtained from the spontaneous fermentation of mezcal

Mezcal from Tamaulipas (Me´xico) is produced by spontaneous alcoholic fermentation using Agave spp. musts, which are rich in fructose. In this study eight Saccharomyces cerevisiae isolates obtained at the final stage of fermentation from a traditional mezcal winery were analysed in three semisynthetic media. Medium M1 had a sugar content of 100 g l-1 and a glucose/fructose (G/F) of 9:1. Medium M2 had a sugar content of 100 g l-1 and a G/F of 1:9. Medium M3 had a sugar content of 200 g l-1 and a G/F of 1:1. In the three types of media tested, the highest ethanol yield was obtained from the glucophilic strain LCBG-3Y5, while strain LCBG-3Y8 was highly resistant to ethanol and the most fructophilic of the mezcal strains. Strain LCBG-3Y5 produced more glycerol (4.4 g l-1) and acetic acid (1 g l-1) in M2 than in M1 (1.7 and 0.5 g l-1, respectively), and the ethanol yields were higher for all strains in M1 except for LCBG-3Y5, -3Y8 and the Fermichamp strain. In medium M3, only the Fermichamp strain was able to fully consume the 100 g of fructose l-1 but left a residual 32 g of glucose l-1. Regarding the hexose transporters, a high number of amino acid polymorphisms were found in the Hxt1p sequences. Strain LCBG-3Y8 exhibited eight unique amino acid changes, followed by the Fermichamp strain with three changes. In Hxt3p, we observed nine amino acid polymorphisms unique for the Fermichamp strain and five unique changes for the mezcal strains

Biotransformation of Chromium (VI) via a Reductant Activity from the Fungal Strain Purpureocillium lilacinum

Industrial effluents from chromium-based products lead to chromium pollution in the environment. Several technologies have been employed for the removal of chromium (Cr) from the environment, including adsorption, ion-exchange, bioremediation, etc. In this study, we isolated a Cr (VI)-resistant fungus, Purpureocillium lilacinum, from contaminated soil, which could reduce chromium. We also characterized a reductant activity of dichromate found in the cellular fraction of the fungus: optimal pH and temperature, effect of enzymatic inhibitors and enhancers, metal ions, use of electron donors, and initial Cr (VI) and protein concentration. This study also shows possible mechanisms that could be involved in the elimination of this metal. We observed an increase in the reduction of Cr (VI) activity in the presence of NADH followed by that of formate and acetate, as electron donor. This reduction was highly inhibited by EDTA followed by NaN3 and KCN, and this activity showed the highest activity at an optimal pH of 7.0 at 37 °C with a protein concentration of 3.62 µg/mL

Phytotoxic Potential of Secondary Metabolites and Semisynthetic Compounds from Endophytic Fungus Xylaria feejeensis Strain SM3e-1b Isolated from Sapium macrocarpum

Bioactivity-directed fractionation of the combined culture medium and mycelium extract of the endophytic fungus Xylaria feejeensis strain SM3e-1b, isolated from Sapium macrocarpum, led to the isolation of three known natural products: (4<i>S</i>,5<i>S</i>,6<i>S</i>)-4-hydroxy-3-methoxy-5-methyl-5,6-epoxycyclohex-2-enone or coriloxine, <b>1</b>; 2-hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, <b>2</b>; and 2,6-dihydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione or fumiquinone B, <b>3</b>. This is the first report of compound <b>3</b> being isolated from this species. Additionally, four new derivatives of coriloxine were prepared: (4<i>R</i>,5<i>S</i>,6<i>R</i>)-6-chloro-4,5-dihydroxy-3-methoxy-5-methylcyclohex-2-enone, <b>4</b>; 6-hydroxy-5-methyl-3-(methylamino)­cyclohexa-2,5- diene-1,4-dione, <b>5</b>; (4<i>R</i>,5<i>R</i>,6<i>R</i>)-4,5-dihydroxy-3-methoxy-5-methyl-6-(phenylamino)­cyclohex-2-enone, <b>6</b>; and 2-((4-butylphenyl)­amino)-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, <b>7</b>. X-ray analysis allowed us to unambiguously determine the structures and absolute configuration of semisynthetic derivatives <b>4</b>, <b>5</b>, and <b>6</b>. The phytotoxic activity of the three isolated natural products and the coriloxine derivatives is reported. Germination of the seed, root growth, and oxygen uptake of the seedlings of Trifolium pratense, Medicago sativa, Panicum miliaceum, and Amaranthus hypochondriacus were significantly inhibited by all of the tested compounds. In general, they were more effective inhibiting root elongation than suppressing the germination and seedling oxygen uptake processes as shown by their IC₅₀ values

Brosimum Alicastrum as a Novel Starch Source for Bioethanol Production

Ramon (Brosimum alicastrum) is a forest tree native to the Mesoamerican region and the Caribbean. The flour obtained from Ramon seeds is 75% carbohydrate, of which 63% is starch, indicating its potential as a novel raw material for bioethanol production. The objective of this study was to produce ethanol from Ramon flour using a 90 °C thermic treatment for 30 min and a native yeast strain (Candida tropicalis) for the fermentation process. In addition, the structure of the flour and the effects of pretreatment were observed via scanning electron microscopy. The native yeast strain was superior to the commercial strain, fermenting 98.8% of the reducing sugar (RS) at 48 h and generating 31% more ethanol than commercial yeast. One ton of flour yielded 213 L of ethanol. These results suggest that Ramon flour is an excellent candidate for ethanol production. This is the first report on bioethanol production using the starch from Ramon seed flour and a native yeast strain isolated from this feedstock. This alternative material for bioethanol production minimizes the competition between food and energy production, a priority for Mexico that has led to significant changes in public policies to enhance the development of renewable energies

Alternativas tecnológicas para la elaboración y la conservación de productos panificados

329 págs.-- 1ª ed.-- Córdoba (Argentina): Universidad Nacional de Córdoba, 2009.Índice: 1. Masas congeladas / Pablo Daniel Ribotta, Pedro de Alcântara Pessoa Filho, Carmen Cecilia Tadini.- 2. Productos precocidos congelados y refrigerados / Cristina Molina Rosell, Concha Collar.- 3. Utilización de microondas en panificación / Manuel Gómez Pallarés, Bonastre Oliete Mayorga.- 4. Elaboración de productos de panificación especialmente formulados / Manuel Gómez Pallarés, Carmen Cecilia Tadini, Gabriela Teresa Pérez.- 5. Procesos alternativos de nixtamalización del maíz y productos derivados / Eduardo San Martín–Martínez, Ruth Pedroza–Islas, Dora Luz Villagómez–Zavala, Fernando Martínez-Bustos.- 6. Procesos de obtencion de harina de maíz no–nixtamalizada y sus usos / Elevina Pérez Sira, Lilliam Sívoli, Romel Guzmán.- 7. Efecto de la formulación sobre la conservación de los productos de panificación / Concha Collar, Alberto Edel León, Cristina Molina Rosell.- 8. Materiales de envases y sistemas de envasado de productos de panificación / Abel Guarda, María José Galotto, Márcia Arocha Gularte.- 9. Aplicación de biopolímeros formadores de película en productos de panificación / Jesus Alberto Quezada Gallo, Rubén Moreno Terrazas Casildo, Ruth Pedroza Islas, Patricia Lappe–Oliveras.El pan es un alimento que se consume desde épocas remotas y que forma parte de la dieta tradicional de una vasta población localizada en América, Europa, Medio Oriente e India. Su formulación incluye tres componentes básicos: harina, agua y sal. La harina de trigo es la más utilizada, aunque también se emplean harinas provenientes de otros cereales como maíz, arroz, cebada y centeno. Con el correr del tiempo y en las diferentes regiones se han ido introduciendo en esta formulación diversos componentes y formas de procesamiento, lo que ha dado origen a un sinnúmero de productos.Dichos productos responden a las exigencias del consumidor, las que han ido variando con el correr del tiempo. Desde hace ya varios años no sólo se reclaman adecuadas propiedades nutricionales sino que se exigen alimentos de alta calidad, mínimamente procesados, libres de aditivos, seguros desde el punto de vista microbiológico y que posean beneficios para la salud.Los adelantos producidos en la Ciencia y la Tecnología de Alimentos han facilitado el paulatino conocimiento de un sistema sumamente complejo como es la matriz panaria. Esto ha permitido mejorar las propiedades y calidad del pan, a la vez que la introdución en forma paralela de nuevos equipos y tecnología de procesamiento han conducido a la obtención de nuevos productos.Este libro es producto de la Acción 106AC0301 – "Obtención de productos de panificación para necesidades específicas" – PANXTODOS, la cual es patrocinada por el Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (CYTED).Peer reviewe