Fermentation, losses, and aerobic stability of sugarcane silages treated with chemical or bacterial additives

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Combining ability of Phaseolus vulgaris L. for resistance to common bacterial blight

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inoculante enzimático-bacteriano, composição química e parâmetros fermentativos das silagens dos capins Tanzânia e Mombaça

Objetivou-se, com o presente trabalho, avaliar os efeitos de idades de colheita e do uso de inoculante enzimático-bacteriano sobre os parâmetros de fermentação, de composição química e digestibilidade in vitro da matéria seca (DIVMS) das silagens dos cultivares Tanzânia e Mombaça (Panicum maximum Jacq.). As forragens foram colhidas aos 45 e 60 dias após o corte de uniformização, submetidas a dois tratamentos (A - Ensilagem sem aditivo [Controle]; B - Ensilagem com adição de inoculante enzimático-bacteriano) e distribuídas em um delineamento inteiramente casualizado em esquema fatorial (dois capins x duas inoculações x duas idades de corte), com três repetições. O conteúdo de MS das silagens confeccionadas com as plantas colhidas aos 60 dias de rebrota foi superior àquele das silagens colhidas com 45 dias. As silagens confeccionadas com as plantas colhidas aos 45 dias de rebrota apresentaram os maiores teores de PB (11,9%). Não se observaram efeitos das silagens, dos tratamentos e das idades de corte sobre os teores de hemicelulose, celulose e DIVMS e valores de pH e N-NH3. As silagens do capim-tanzânia apresentaram os maiores teores de MS, FDN, FDA, ácido lático e ácido butírico, enquanto as de capim-mombaça, os de PB e de ácido acético. A adição de inoculante enzimático-bateriano promoveu silagens com menores teores de MS, PB e lignina que as não-tratadas. Os capins tanzânia e mombaça não apresentaram limitações ao processo de ensilagem. O inoculante enzimático-bacteriano não melhorou as características qualitativas, fermentativas e nutricionais das silagens avaliadas.

Interaction between vitamin K nutriture and bacterial overgrowth in hypochlorhydria induced by omeprazole

Subjects taking a hydrogen pump blocking agent (omeprazole) develop bacterial overgrowth of the small intestine. We tested the hypothesis that this bacterial overgrowth produces menaquinones, which would meet the Vitamin requirement in situations of vitamin K deficiency. In a crossover-type design, 13 healthy Volunteers eating a phylloquinone-restricted diet for 35 d were randomly assigned to take omeprazole during the first period of study or starting on day 15 until the end of the study. Coagulation times, serum osteocalcin [total osteocalcin and undercarboxylated osteocalcin (ucOC)], plasma phylloquinone, urinary gamma-carboxyglutamic acid, and plasma undercarboxylated prothrombin (PIVKA-II) were measured. Plasma phylloquinone concentrations declined 82% with dietary phylloquinone restriction (P < 0.05) and were not significantly different in the period when the diet was combined with omeprazole treatment (P > 0.05), the mean value for PIVKA-II during the phylloquinone-restricted diet significantly increased 5.7-fold from baseline (P < 0.05); however, the combination of omeprazole treatment and the phylloquinone-restricted diet significantly reduced PIVKA-II values by 21% (P < 0.05) compared with the diet period alone. There were no alterations in total or percentage ucOC concentrations during the phylloquinone-restricted diet or during the period of diet plus omeprazole treatment. Our data support the hypothesis that bacterial overgrowth results in the synthesis and absorption of menaquinones. These menaquinones contribute to vitamin K nutriture during dietary phylloquinone restriction, but not enough to restore normal vitamin K status.

The effects of bacterial leaching on metal partitioning in sewage sludge

The partitioning of Mn, Al, Zn, Cu and Ti ions in municipal sewage sludge was investigated before and after bioleaching processes effectuated by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. Oxidation reduction potential increase and pH decrease were obtained as a result of bacterial activity. A less pronounced and constant decrease was obtained with A. ferrooxidans, whereas A. thiooxidans presented a lag phase before a steep pH decrease. Metal solubilization was accomplished in experimental systems supplemented with energy source, Fe2+ for A. ferrooxidans and S-0 for A. thiooxidans. Solubilization efficiency differed for each metal except for Al, and was relatively similar for either organism. Metal partitioning was conducted using five-step sequential extraction procedure before and after the bioleaching. The results indicated that Zn and Mn ions were mostly associated with the organic fraction, whereas Cu, Al and Ti ions with the sulphide/ residue fraction. The bioleaching process caused prompt solubilization of metals mostly associated with the more labile fractions (exchangeable, adsorbed and organically bound metals), whereas those associated to the less labile ones (EDTA and sulphide/residue fractions) were exchanged towards more labile fractions.

Characterization of methylcellulose produced from sugar cane bagasse cellulose: Crystallinity and thermal properties

In the present work, methylcellulose produced from sugar cane bagasse was characterized by FTIR, WAXD, DTA and TGA techniques. Two samples were synthesized: methylcellulose A and rnethylcellulose B. The only difference in the process was the addition of fresh reactants during the preparation of methylcellulose B. The ratio between the absorption intensities of the C-H stretching band at around 2900 cm(-1) and C-H stretching at around 3400 cm(-1) for methylcellulose B is higher than for methylcellulose A, indicating that methylcellulose B showed an increase in the degree of substitution (DS). Methylcellulose A presents a more heterogeneous structure, which is similar to the original cellulose as seen through FTIR and DTA. Methylcellulose B showed thermal properties similar to commercial methylcellulose. The modification of rnethylcellulose preparation method allows the production of a material with higher DS, crystallinity and thermal stability in relation to the original cellulose and to methylcellulose A. (c) 2006 Elsevier Ltd. All rights reserved.

Effect of different irrigation solutions and calcium hydroxide on bacterial LPS

Aim To evaluate the effect of biomechanical preparation with different irrigating solutions and calcium hydroxide dressing in dog root canals containing bacterial endotoxin (lipopolysaccharides; LPS).Methodology One hundred and forty premolar roots from seven dogs were filled with Escherichia coli LPS for 10 days (three roots were lost during histological processing). The following irrigating solutions were used for biomechanical preparation: 1% (group I, n = 20), 2.5% (group II, n = 19) and 5% sodium hypochlorite (group III, n = 19), 2% chlorhexidine digluconate (group IV, n = 20) and physiological saline solution (group V, n = 19). In group VI (n = 20), the LPS solution was maintained in the root canal during the entire experiment and in group VII (n = 20), after biomechanical preparation with saline solution, the root canals were filled with a calcium hydroxide dressing (Calen; control). After 60 days, the animals were sacrificed and the following parameters of periapical disease were evaluated: (a) inflammatory infiltrate, (b) periodontal ligament thickness, (c) cementum resorption and (d) bone resorption. Scores were given and data were analysed statistically with the Kruskal-Wallis and Dunn tests (P < 0.05).Results Histopathological evaluation showed that groups I-VI had more inflammatory infiltrate, greater periodontal ligament thickening and greater cementum and bone resorption (P < 0.05) compared to group VII, which received the calcium hydroxide intracanal dressing.Conclusions Biomechanical preparation with the irrigating solutions did not inactivate the effects of the endotoxin but the calcium hydroxide intracanal dressing did appear to inactivate the effects induced by the endotoxin in vivo.

BACTERIAL LEACHING OF URANIUM ORE FROM FIGUEIRA-PR, BRAZIL, AT LABORATORY AND PILOT-SCALE

A bacterial leaching program was carried out in order to evaluate the potential of applying this process to leach uranium from the ore of Figueira-PR, Brazil. The experiments were carried out in shake flasks, column percolation (laboratory and semipilot scale) and in heap leaching. In shake flasks and in column percolation experiments at laboratory scale, bacterial activity on the ore was confirmed: approximately 60% of uranium was leached, against around 30% in sterilized controls. Column percolation experiments at semipilot scale and heap leaching (850 tons of ore) showed uranium extractions of approximately 50%. In both experiments, a complementary sulfuric acid attack, after the bacterial leaching phase, was necessary to reach this level of uranium extraction.

Lability of heavy metal species in aquatic humic substances characterized by ion exchange with cellulose phosphate

Labile metal species in aquatic humic substances (HSs) were characterized by ion exchange on cellulose phosphate (CellPhos) by applying an optimized batch procedure. The HSs investigated were pre-extracted from humic-rich waters by ultrafiltration and a resin XAD 8 procedure. The HS-metal species studied were formed by complexation with Cd(II), Ni(II), Cu(II), Mn(II) and Pb(II) as a function of time and the ratio ions to HSs. The kinetics and reaction order of this exchange process were studied. At the beginning (<3 min), the labile metal fractions are separated relatively quickly. After 3 min, the separation of the metal ions proceeds with uniform half-lives of about 12-14 min, revealing rather slow first-order kinetics. The metal exchange between HSs and CellPhos exhibited the following order of metal lability with the studied HSs: Cu > Pb > Mn > Ni > Cd. The required metal determinations were carried out by atomic absorption spectrometry.

Thermal decomposition of microcrystalline cellulose and its pure and containing adsorbed cadmium cations derivatives.

We have studied the thermal decomposition of the microcrystalline cellulose and some of its derivative such as pure carboxymethylcellulose (CMCH), phosphate cellulose (FOSCEL) and oxycellulose (OXICEL) and also these same derivatives containing adsorbed cadmium cations. We have used the TG,DTG tecniques in order to determine the quantity of retained cadmium II cations on the surface of these adsorbents.

Utilization of Spirillum volutans for monitoring the toxicity of effluents of a cellulose and paper industry

The motility of Spirillum volutans was used for monitoring the toxicity of effluents of a cellulose and paper industry. Results indicated that there was no correlation between organic content and the toxic effects of the residues in the effluents. The effluents from the chlorination step and from the sludge ponds presented the highest toxicity. on the other hand, the final effluent from the biological treatment basin had no toxic agent. This bioassay showed to be a simple and reliable technique that can be used for adequately monitoring the toxicity of effluents.