Alternativa productiva para el aprovechamiento del residuo cachaza

Este trabajo de investigación, busca ofrecer al sector panelero de Colombia nuevas estrategias eco-eficientes y amigables con el medio ambiente, en pro de fortalecer las buenas prácticas agrícolas, que contribuyan con la gestión óptima de los residuos que se crean alrededor de la cadena de producción de la panela. Teniendo en cuenta que la obtención de desechos tanto orgánicos como inorgánicos, genera un impacto medioambiental negativo, se pudo identificar una de estas fuentes de contaminación, a través de un proceso de observación. Ésta es conocida como la Cachaza, la cual se genera dentro de un procedimiento denominado Limpieza del Dulce de Caña. Inicialmente, la caña se muele a través de una trituradora que exprime dulce sin tratamiento, el cual pasa por un ducto hasta regarse sobre una primera paila, donde se le aplica balso. Por medio del calor que produce una hornilla sobre la que se coloca dicha paila, se realiza un proceso de separación, el residuo consolidado en una espuma espesa, comienza a flotar por encima del dulce, siendo extraída a medida que va saliendo y depositada en otros recipientes. Considerando constantes prácticas como el vertimiento de la Cachaza sobre algunas fuentes hídricas (ríos, lagunas, etc.) y cultivos de caña ya fermentados (que elaboran nutrientes negativos sobre los mismos); se profundizará sobre los diferentes impactos ambientales que se originan en éste proceso agroindustrial. El objetivo principal del presente trabajo de investigación, consiste en la implementación de un proyecto de logística inversa, formulando estrategias para el procesamiento de la Cachaza a implementar en un trapiche de la zona de Rio negro a fin de reutilizar este residuo generando subproductos que aporten a la mitigación del impacto ambiental, dando así un valor agregado a toda la cadena. Mediante un análisis costo beneficio se evaluará qué tan fácil o difícil resulta la implementación de dicho proyecto, el cual al incluir un proceso adicional a la cadena de producción de la panela generara un suplemento alimenticio para los equinos y aprovechara el 100% de sus residuos a muy bajo costo.

Método rápido para triagem da citotoxicidade geral parte II : foto-toxicidade

Um método previamente desenvolvido destinado a afzer a triagem rápida e o escalonamento da toxicidade geral exercida por agentes físicos e químicos tendo como modelo a Saccharomyces cerevisiae é usado para estudar os efeitos da radiação UVB de banda estreita (UVB-nb). As condições de experiementação para avaliar os efeitos tóxicos expressos na forma de inibição do crescimento foram estabelecidas na primeira parte deste trabalho. A segunda parte trata da toxicidade geral induzida pela radiação ultravioleta B banda estreita (311-312 nm) (UVB-nb). Concentrações celulares conhecidas de levedura foram expostas a 550 µ W/cm2 de UVB-nb por tempos diferentes e a proliferação comparada com grupos de controlo não irradiados. Os resultados demonstraram que os efeitos na proliferação produzida por exposição a radiação UVB-nb até trinta minutos quando comparados com os controlos não tinham significado estatístico.

Tolerance of ruminant animals to high dose in-feed administration of a selenium-enriched yeast

The objective of the study was to determine if there were adverse effects on animal health and performance when a range of ruminant animals species were fed at least 10 times the maximum permitted European Union (EU) selenium (Se) dietary inclusion rate (0.568 mg Se/kg DM) in the form of selenium enriched yeast (SY) derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060. In a series of studies, dairy cows, beef cattle, calves and lambs were offered either a control diet which contained no Se supplement or a treatment diet which contained the same basal feed ingredients plus a SY supplement which increased total dietary Se from 0.15 to 6.25, 0.20 to 6.74, 0.15 to 5.86 and 0.14 to 6.63 mg Se/kg DM, respectively. The inclusion of the SY supplement (P < 0.001) increased whole blood Se concentrations, reaching maximum mean values of 716, 1,505, 1,377, and 724 ng Se/mL for dairy cattle, beef cattle, calves and lambs, respectively. Selenomethionine accounted for 10% of total whole blood Se in control animals whereas the proportion in SY animals ranged between 40 and 75%. Glutathione peroxidase (EC 1.11.1.9) activity was higher (P < 0.05) in SY animals when compared with controls. A range of other biochemical and hematological parameters were assessed, but few differences of biological significance were established between treatments groups. There were no differences between treatment groups within each species with regard to animal physical performance or overall animal health. It was concluded that there were no adverse effects on animal health, performance and voluntary feed intake to the administration of at least ten times the EU maximum, or approximately twenty times the US FDA permitted concentration of dietary Se in the form of SY derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060.

Selenium supplementation of lactating dairy cows: effects on milk production and total selenium content and speciation in blood, milk and cheese

Forty-multiparous Holstein cows were used in a 16-wk continuous design study to determine the effects of either selenium (Se) source, selenized yeast (SY) (derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060 Sel-Plex®) or sodium selenite (SS), or inclusion rate of SY on Se concentration and speciation in blood, milk and cheese. Cows received ad libitum a TMR with 1:1 forage:concentrate ratio on a dry matter (DM) basis. There were four diets (T1-T4) which differed only in either source or dose of Se additive. Estimated total dietary Se for T1 (no supplement), T2 (SS), T3 (SY) and T4 (SY) was 0.16, 0.30, 0.30 and 0.45 mg/kg DM, respectively. Blood and milk samples were taken at 28 day intervals and at each time point there were positive linear effects of SY on Se concentration in blood and milk. At day 112 blood and milk Se values for T1-T4 were 177, 208, 248, 279 ± 6.6 and 24, 38, 57, 72 ± 3.7 ng/g fresh material, respectively and indicate improved uptake and incorporation of Se from SY. While selenocysteine (SeCys) was the main selenised amino acid in blood its concentration was not markedly affected by treatment, but the proportion of total Se as selenomethionine (SeMet) increased with increasing inclusion rate of SY. In milk, there were no marked treatment effects on SeCys content, but Se source had a marked effect on the proportion of total Se as SeMet. At day 112 replacing SS (T2) with SY (T3) increased the SeMet concentration of milk from 36 to 111 ng Se/g and its concentration increased further to 157 ng Se/g as the inclusion rate of SY increased further (T4) to provide 0.45 mg Se/kg TMR. Neither Se source nor inclusion rate effected the keeping quality of milk. At day 112, milk from T1, T2, and T3 was made into a hard cheese and Se source had a marked effect on total Se and the proportion of total Se comprised as either SeMet or SeCys. Replacing SS (T2) with SY (T3) increased total Se, SeMet and SeCys content from 180 to 340 ng Se/g, 57 to 153 ng Se/g and 52 to 92 ng Se/g, respectively. Key words: dairy cow, milk and cheese, selenomethionine, selenocysteine, milk keeping quality

Selenium supplementation of lactating dairy cows: Effect on selenium concentration in blood, milk, urine and feces

The objectives were to determine effects of graded levels of selenized yeast derived from a specific strain of Saccharomyces cerevisiae (CNCM I-3060) on animal performance and in selenium concentrations in the blood, milk, feces, and urine of dairy cows compared with sodium selenite; and to provide preliminary data on the proportion of selenium as selenomethionine in the milk and blood. Twenty Holstein cows were used in a 5 × 5 Latin square design study in which all cows received the same total mixed rations, which varied only in source or concentration of dietary selenium. There were 5 experimental treatments. Total dietary selenium of treatment 1, which received no added selenium, was 0.15 mg/kg of dry matter, whereas values for treatments 2, 3, and 4, derived from selenized yeast, were 0.27, 0.33, and 0.40 mg/kg of dry matter, respectively. Treatment 5 contained 0.25 mg of selenium obtained from sodium selenite/kg of dry matter. There were no significant treatment effects on animal performance, and blood chemistry and hematology showed few treatment effects. Regression analysis noted significant positive linear effects of increasing dietary selenium derived from selenized yeast on selenium concentrations in the milk, blood, urine, and feces. In addition, milk selenium results indicated improved bioavailability of selenium from selenized yeast, compared with sodium selenite. Preliminary analyses showed that compared with sodium selenite, the use of selenized yeast increased the concentration of selenomethionine in the milk and blood. There was no indication of adverse effects on cow health associated with the use of selenized yeast.

Nuclear magnetic resonance structure of the nucleic acid-binding domain of severe acute respiratory syndrome coronavirus nonstructural protein 3

The nuclear magnetic resonance (NMR) structure of a globular domain of residues 1071 to 1178 within the previously annotated nucleic acid-binding region (NAB) of severe acute respiratory syndrome coronavirus nonstructural protein 3 (nsp3) has been determined, and N- and C-terminally adjoining polypeptide segments of 37 and 25 residues, respectively, have been shown to form flexibly extended linkers to the preceding globular domain and to the following, as yet uncharacterized domain. This extension of the structural coverage of nsp3 was obtained from NMR studies with an nsp3 construct comprising residues 1066 to 1181 [ nsp3(1066-1181)] and the constructs nsp3(1066-1203) and nsp3(1035-1181). A search of the protein structure database indicates that the globular domain of the NAB represents a new fold, with a parallel four-strand beta-sheet holding two alpha-helices of three and four turns that are oriented antiparallel to the beta-strands. Two antiparallel two-strand beta-sheets and two 3(10)-helices are anchored against the surface of this barrel-like molecular core. Chemical shift changes upon the addition of single-stranded RNAs (ssRNAs) identified a group of residues that form a positively charged patch on the protein surface as the binding site responsible for the previously reported affinity for nucleic acids. This binding site is similar to the ssRNA-binding site of the sterile alpha motif domain of the Saccharomyces cerevisiae Vts1p protein, although the two proteins do not share a common globular fold.

Population performance of collembolans feeding on soil fungi from different ecological niches

The potential reproductive value of arbuscular mycorrhizal fungi (Gloinus intraradices and Glomus invermaium), root pathogenic fungi (Rhizoctonia solani and Fusarium culmorum) and saprotrophic fungi (Penicillium hordei and Trichoderma harzianum) were examined for the collembolans Folsomia candida Willem and Folsomia fimetaria L. Dried baker's yeast (Saccharomyces cerevisiae) was used as a reference standard food in laboratory cultures. Collembolan performance was determined as final size, fecundity and population growth rate after when fed the fungal food sources for 31 days. The mycorrhizal fungi gave the least growth and fecundity compared with the other fungi, but G. intraradices gave good fecundity for F. candida. In terms of growth, Baker's yeast was a high-quality food for both adults and juveniles of both species, but it was a poorer food in terms of fecundity of F. candida. Preference of the fungi in all possible pairwise combinations showed that although F. fimetaria did not perform well on Glomus spp. and F. candida did not grow well on Glomus spp. their preference for these fungi did not reflect this. The highest fecundity was seen with the root pathogen F. culmorum. Different quality indicators such as the C:N ratio of the fungal food sources as well as other biological parameters are discussed in relation to their reproductive value and Collembola preferential feeding. (c) 2007 Elsevier Ltd. All rights reserved.

Constrained models of evolution lead to improved prediction of functional linkage from correlated gain and loss of genes

Motivation: We compare phylogenetic approaches for inferring functional gene links. The approaches detect independent instances of the correlated gain and loss of pairs of genes from species' genomes. We investigate the effect on results of basing evidence of correlations on two phylogenetic approaches, Dollo parsminony and maximum likelihood (ML). We further examine the effect of constraining the ML model by fixing the rate of gene gain at a low value, rather than estimating it from the data. Results: We detect correlated evolution among a test set of pairs of yeast (Saccharomyces cerevisiae) genes, with a case study of 21 eukaryotic genomes and test data derived from known yeast protein complexes. If the rate at which genes are gained is constrained to be low, ML achieves by far the best results at detecting known functional links. The model then has fewer parameters but it is more realistic by preventing genes from being gained more than once. Availability: BayesTraits by M. Pagel and A. Meade, and a script to configure and repeatedly launch it by D. Barker and M. Pagel, are available at http://www.evolution.reading.ac.uk .

EfeUOB (YcdNOB) is a tripartite, acid-induced and CpxAR-regulated, low-pH Fe2+ transporter that is cryptic in Escherichia coli K-12 but functional in E-coli O157 : H7

Escherichia coli possesses iron transporters specific for either Fe2+ or Fe3+. Although Fe2+ is far more soluble than Fe3+, it rapidly oxidizes aerobically at pH >= 7. Thus, FeoAB, the major Fe2+ transporter of E. coli, operates anaerobically. However, Fe2+ remains stable aerobically under acidic conditions, although a low-pH Fe2+ importer has not been previously identified. Here we show that ycdNOB (efeUOB) specifies the first such transporter. efeUOB is repressed at high pH by CpxAR, and is Fe2+-Fur repressed. EfeU is homologous to the high-affinity iron permease, Ftr1p, of Saccharomyces cerevisiae and other fungi. EfeO is periplasmic with a cupredoxin N-terminal domain; EfeB is also periplasmic and is haem peroxidase-like. All three Efe proteins are required for Efe function. The efeU gene of E. coli K-12 is cryptic due to a frameshift mutation - repair of the single-base-pair deletion generates a functional EfeUOB system. In contrast, the efeUOB operon of the enterohaemorrhagic strain, O157:1147, lacks any frameshift and is functional. A 'wild-type' K-12 strain bearing a functional EfeUOB displays a major growth advantage under aerobic, low-pH, low-iron conditions when a competing metal is provided. Fe-55 transport assays confirm the ferrous iron specificity of EfeUOB.

Eukaryotic expression: developments for structural proteomics

The production of sufficient quantities of protein is an essential prelude to a structure determination, but for many viral and human proteins this cannot be achieved using prokaryotic expression systems. Groups in the Structural Proteomics In Europe ( SPINE) consortium have developed and implemented high- throughput ( HTP) methodologies for cloning, expression screening and protein production in eukaryotic systems. Studies focused on three systems: yeast ( Pichia pastoris and Saccharomyces cerevisiae), baculovirusinfected insect cells and transient expression in mammalian cells. Suitable vectors for HTP cloning are described and results from their use in expression screening and protein-production pipelines are reported. Strategies for coexpression, selenomethionine labelling ( in all three eukaryotic systems) and control of glycosylation ( for secreted proteins in mammalian cells) are assessed.

Relationship between sublethal injury and microbial inactivation by the combination of high hydrostatic pressure and citral or tert-butyl hydroquinone

The aim was to investigate (i) the occurrence of sublethal injury in Listeria monocytogenes, Escherichia coli, and Saccharomyces cerevisiae after high hydrostatic pressure (HHP) treatment as a function of the treatment medium pH and composition and (ii) the relationship between the occurrence of sublethal injury and the inactivating effect of a combination of HHP and two antimicrobial compounds, tert-butyl hydroquinone (TBHQ) and citral. The three microorganisms showed a high proportion of sublethally injured cells (up to 99.99% of the surviving population) after HHP. In E. coli and L. monocytogenes, the extent of inactivation and sublethal injury depended on the pH and the composition of the treatment medium, whereas in S. cerevisiae, inactivation and sublethal injury were independent of medium pH or composition under the conditions tested. TBHQ alone was not lethal to E. coli or L. monocytogenes but acted synergistically with HHP and 24-h refrigeration, resulting in a viability decrease of >5 log(10) cycles of both organisms. The antimicrobial effect of citral depended on the microorganism and the treatment medium pH. Acting alone for 24 h under refrigeration, 1,000 ppm of citral caused a reduction of 5 log(10) cycles of E. coli at pH 7.0 and almost 3 log(10) cycles of L. monocytogenes at pH 4.0. The combination of citral and HHP also showed a synergistic effect. Our results have confirmed that the detection of sublethal injury after HHP may contribute to the identification of those treatment conditions under which HHP may act synergistically with other preserving processes.

In vitro investigation into the potential prebiotic activity of honey oligosaccharides

The effect of honey oligosaccharides on the growth of fecal bacteria was studied using an in vitro fermentation system. Prior to treatment, glucose and fructose (31.73 and 21.41 g/100 g of product, respectively) present in honey, which would be digested in the upper gut, were removed to avoid any influence on bacterial populations in the fermentations. Nanofiltration, yeast (Saccharomyces cerevisiae) treatment, and adsorption onto activated charcoal were used to remove monosaccharides. Prebiotic (microbial fermentation) activities of the three honey oligosaccharide fractions and the honey sample were studied and compared with fructooligosaccharide (FOS), using 1% (w/v) fecal bacteria in an in vitro fermentation system (10 mg of carbohydrate, 1.0 mL of basal medium). A prebiotic index (PI) was calculated for each carbohydrate source. Honey oligosaccharides seem to present potential prebiotic activity (PI values between 3.38 and 4.24), increasing the populations of bifidobacteria and lactobacilli, although not to the levels of FOS (PI of 6.89).

Selenium supplementation of lactating dairy cows: effects on milk production and total selenium content and speciation in blood, milk and cheese

Forty multiparous Holstein cows were used in a 16-week continuous design study to determine the effects of either selenium (Se) source, selenised yeast (SY) (derived from a specific strain of Saccharomyces cerevisiae CNCM 1-3060) or sodium selenite (SS), or Se inclusion rate in the form of SY in the diets of lactating dairy cows on the Se concentration and speciation in blood, milk and cheese. Cows received ad libitum a total mixed ration (TMR) with a 1 : 1 forage: concentrate ratio on a dry matter (DM) basis. There were four diets (T-1 to T-4), which differed only in either source or dose of Se additive. Estimated total dietary Se for T, (no supplement), T-2 (SS), T-3 (SY) and T-4 (SY) was 0.16, 0.30, 0.30 and 0.45 mg/kg DM, respectively. Blood and milk samples were taken at 28-day intervals and at each time point there were positive linear effects of Se in the form of SY on the Se concentration in blood and milk. At day 112 blood and milk Se values for T-1 to T-4 were 177, 208, 248 and 279 +/- 6.6 and 24, 38, 57 and 72 +/- 3.7 ng/g fresh material, respectively, and indicate improved uptake and incorporation of Se from SY. In whole blood, selenocysteine (SeCys) was the main selenised amino acid and the concentration of selenomethionine (SeMet) increased with the increasing inclusion rate of SY In milk, there were no marked treatment effects on the SeCys content, but Se source had a marked effect on the concentration of SeMet. At day 112 replacing SS (T-2) with SY (T-3) increased the SeMet concentration of milk from 36 to 111 ng Se/g and its concentration increased further to 157ng Se/g dried sample as the inclusion rate of SY increased further (T-4) to provide 0.45 mg Se/kg TMR. Neither Se source nor inclusion rate affected the keeping quality of milk. At day 112 milk from T-1, T-2 and T-3 was made into a hard cheese and Se source had a marked effect on total Se and the concentration of total Se comprised as either SeMet or SeCys. Replacing SS (T-2) with SY (T-3) increased total Se, SeMet and SeCys content in cheese from 180 to 340 ng Se/g, 57 to 153 ng Se/g and 52 to 92 ng Se/g dried sample, respectively. The use of SY to produce food products with enhanced Se content as a means of meeting the Se requirements is discussed

Isolation of culturable yeasts from market wines and evaluation of the 5 center dot 8S-ITS rDNA sequence analysis for identification purposes

Aims: To test the possibility that wines available in the marketplace may contain culturable yeasts and to evaluate the 5.8S-ITS rDNA sequence analysis as adequate means for the identification of isolates. Methods and Results: As a case study, typical Greek wines were surveyed. Sequence analysis of the 5.8S-ITS rDNA was tested for its robustness in species or strain identification. Sixteen isolates could be assigned into the species Brettanomyces bruxellensis, Saccharomyces cerevisiae and Rhodotorula pinicola, whereas four isolates could not be safely identified. B. bruxellensis was the dominant species present in house wines, while non-Saccharomyces sp. were viable in aged wines of high alcohol content. Conclusions: Yeast population depends on postfermentation procedures or storage conditions. Although 5.8S-ITS rDNA sequence analysis is generally a rapid method to identify wine yeast isolates at the species level, or even below that, it may not be sufficient for some genera. Significance and Impact of the Study: This is the first report to show that commercial wines may possess diverse and potentially harmful yeast populations. The knowledge of yeasts able to reside in this niche environment is essential towards integrated quality assurance programmes. For selected species, the 5.8S-ITS rDNA sequence analysis is a rapid and accurate means.

Development of a process for the production and purification of alpha- and beta-galactooligosaccharides from Bifobacterium bifidum NCIMB 41171

Synthesis of prebiotic alpha- and beta-galactooligosaccharides (GOS) using the whole cells of Bifidobacterium bifidum NCIMB 41171 was investigated. Determination of alpha- and beta-galactosidase activities showed them to be at 3 and 205 g(-1) of freeze dried biomass, respectively, and they increased to 5 and 344 U g(-1), respectively, when cells were treated with toluene. Starting with 450-500 mg mL(-1) lactose, maximum GOS concentrations were observed at 80-85% lactose conversions and the mixtures contained oligosaccharides (with a degree of polymerisation >= 3) at 77-109 mg mL(-1) and trans-galactosylated disaccharides between 85-115 mg mL(-1). The GOS yield values varied between 36% and 43%. An alpha-linked disaccharide was detected and its presence was confirmed by gas chromatography mass spectroscopy. Cells were re-used up to 8 times without changes in reaction times or the substrate conversions to GOS. Oligosaccharide synthesis was not inhibited by the presence of glucose or galactose. The mixtures were successfully purified from glucose (92% of glucose removed) by fermentation with Saccharomyces cerevisiae with no losses in the oligosaccharide content and only a small decrease on the galactose. (c) 2006 Elsevier Ltd. All rights reserved.