Jarosite pseudomorph formation from arsenopyrite oxidation using Acidithiobacillus ferrooxidans

In this work, the oxidizing action of a native strain type A. ferrooxidans on a sulphide containing a predominance of arsenopyrite and pyrite has been evaluated. Incubation of the A. ferrooxidans strain in flasks containing 200 mL of T&K medium with the ore (particle size of 106 mu m) at pulp density 8% (w/v) at 35 degrees C on a rotary shaker at 200 rpm resulted in preferential oxidation of the arsenopyrite and the mobilization of 88% of the arsenic in 25 days. Mineralogical characterization of the residue after biooxidation was carried out with FTIR. XRD and SEM/XEDS techniques. An in situ oxidation of the arsenopyrite is suggested on the basis of the frequent appearance of jarosite pseudomorph replacing arsenopyrite, in which the transformations Fe(2+) -> Fe(3+), S(-2) -> S(+6) and As(-1) -> As(+3) -> As(+5) occur for the most part without formation of soluble intermediates, resulting in a type of jarosite that typically contains high concentrations of arsenic (type A-jarosite). However, during pyrite oxidation, dissolution of the constituent Fe and S predominates, which is evidenced by corrosion of pyrite particles with formation of pits, generating a type of jarosite with high quantities of K (type B-jarosite). Lastly, a third type of jarosite (type C-jarosite) also precipitated forming a thin film that covered the grains of pyrite principally. (C) 2010 Elsevier B.V. All rights reserved.

Extracellular tannase from Emericella nidulans showing hypertolerance to temperature and organic solvents

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

Produção de biomassa por fungos Filamentosos em meio de vinhaça de cana-de-açúcar suplementado com melaço

Three species of filamentous fungi, Aspergillus niger, Penicillium fellutanum and Mucor hiemalis, were selected and cultivated in vinasse media with different addition of molasses, pasteurized to 85°C for 30 minutes and with pH = 5.0. The microorganisms, previously adapted to the respective medium for 48 hours, from a solution of 107 spores.ml-1, were cultivated in pure and mixed cultures in Erlenmeyer vessel of 500ml, to 30°C, with constant agitation of 170 rpm, for 24, 48 and 72 hours, with four repetition for each samples. The biomass was separated by vacuum filtration in filter Whatman #1 and dried in oven at 105°C until right weight, the obtained liquid was submited to COD analysis. The datas were statistically analysed using a response surface methodology, to improve the effect on the molasses proportion and culture time, in the biomass production by microorganism in research. According to the obtained results (5.02% of molasses, 55.59h, 70% of spores solution of A. niger and 30% of spores solution of P. fellutanum), cultivating was carried out in Microferm Fermentor New Brunswick for 48 hours at 300 rpm, aired at 1v/v/m, using 5 liters of medium added with 5.0% of molasses on the conditions above described. The average of the results obtained (6.81g.l-1) was higher than the confidence interval (5.937 ; 6.369) and was inside the prediction interval (4.471 ; 7.834) both of them significant at 95% by the statistical test employed.

Broiler Response to Different Wind Speeds

Broiler production in Brazil has turned into a very competitive activity in the late years. Constant innovation leads to higher productivity maintaining the same cost of production, which is a desirable situation. Lately one characteristic for broiler housing in Brazil has been the increase in birds density requiring the use of controlled environment through the use of fan and fogging systems in order to achieve better birds productive performance. Most Brazilian producer already uses cooling equipment however it is still unknown the right way to control the wind speed and direction towards the birds. This present research has the objective to evaluate the effect of the wind speed on the heat transfer from the birds to the environment for broilers at 27 days old. There was used 200 birds, placed in a wind tunnel measuring 1.10 m high by 1.10m wide x 10.0 m of length, and the birds density varied from 9, 16 and 20 birds/m 2. Two wind speed were simulated 340 rpm (1.0 m/s) and 250 rpm (0.3 m/s). The increase in the wind velocity related to the smaller bird densityled to a higher heat loss and to a more uniform temperature distribution in its exposed areas.

Isolamento de fungos produtores de ácido γ-linolênico de solo da Estação Ecologica de Juréia-Itatins, SP

Fungi producing γ-linolenic acid (GLA) were isolated from soil of the Ecological Station of Juréia-Itatins, SP. This essential fatty acid has aroused great interest due to its increasing by applications in pharmaceutical industry. The GLA production by zygomycetous fungi is an alternative way of comparing seed extraction. Thirty-two zygomycetous strains of Mucorales were isolated, most of them belonging to Mucor genus. The GLA production was evaluated after 4 days of incubation at 25°C on a rotary shaker at 150 rpm in medium containing 2% glucose, and 1% yeast extract, following new medium addition (20%) and incubation for an additional period of 3 days at 12°C, without agitation. The GLA production varied according to the microorganism and the strain.

Purificação de lacases PPO-I de Botryosphaeria rhodina

Laccases are glycoprotein polyphenol oxidases which are involved in fungal pathogenicity and they are also useful for biotechnological applications. The ligninolytic ascomycete, Botryosphaeria rhodina, has been studied as producer of exopolysaccharide and PPO-I and PPO-II laccases induced by veratryl alcohol. However, as the induced laccases have not been isolated, the aim of this study was to purify the enzyme and to identify the carbohydrates constituents of the glycosidic moiety. The fungus was cultivated on broth Vogel, 1% glucose and 30.4mM veratryl alcohol during 4.5 days at 28°C/180 rpm. The extracellular fluid showed high carbohydrate concentration and the stability of PPO-I laccase under conditions of refrigeration and freezing at 4°C-18°C over 40 days. The purification was developed by ultrafiltration using a NMWL 100 and 30 kDa membrane, gelfiltration on Sephadex G-100, and ion-exchange chromatography on DEAE-cellulose. The purified laccase was identified as a glycoprotein, weight molecular 113 kDa, consisting of 40% protein and 60% carbohydrate identified by HPAEC-PAD as fucose, galactose, mannose, glucose and glucosamine.

Efeito da cadência de pedalada sobre as respostas metabólica e cardiovascular durante o exercício incremental e de carga constante em indivíduos ativos

The main purpose of this study was to analyze the effect of the pedaling cadence (500 × 100 rpm) on the heart rate (HR) and the blood lactate response during incremental and constant workload exercises in active individuals. Nine active male individuals (20.9 ± 2.9 years old; 73.9 ± 6.5 kg; 1.79 ± 0.9 m) were submitted to two incremental tests, and to 6-8 constant workload tests to determine the intensity corresponding to the maximal steady state lactate (MLSSintens) in both cadences. The maximal power (Pmax) attained during the incremental test, and the MLSSintens were significantly lower at 100 rpm (240.9 ± 12.6 W; 148.1 ± 154.W) compared to 50 rpm (263.9 ± 18.6 W; 186.1 ± 21.2 W), respectively. The HRmax did not change between cadences (50 rpm = 191.1 ± 8.8 bpm; 100 rpm = 192.6 ± 9.9 bpm). Regardless the cadence, the HRmax percentage (70, 80, 90, and 100%) determined the same lactate concentrations during the incremental test. However, when the intensity was expressed in Pmax percentage or in absolute power, the lactate and the HR values were always higher at highest cadences. The HR corresponding to MLSSintens was similar between cadences (50 rpm = 162.5 ± 9.1 bpm; 100 rpm = 160.4 ± 9.2 bpm). Based on these results, it can be conclude that regardless the cadence employed (50 × 100 rpm), the use of the HR to individualize the exercise intensity indicates similar blood lactate responses, and this relationship is also kept in the exercise of constant intensity performed at MLSSintens. On the other hand, the use of the Pmax percentages depend on the cadence used, indicating different physiological responses to a same percentage.

Benzyladenine sprays and senescent flowers removal on postproduction performance of Potted zinnia 'Profusion cherry'

'Profusion Cherry' is a dwarf zinnia with prospect for pot use in Brazil. The success of flowering potted plants depends on its performance during transport and on the period of time that it performs well indoors. Benzyladenine application may retard leaf and flower senescence, increasing postproduction longevity and quality. Senescent flowers removal by consumers, to give a fresh appearance to home flowering potted plant, could influence source-sink relationship and postproduction. This study evaluated the effect of benzyladenine and senescent flowers removal on postproduction performance of 'Profusion Cherry', and observed the senescence symptoms. When plants, produced in greenhouse at São Paulo State, Brazil, had 4 to 5 open flowers, they were sprayed to runoff a single time (20ml/pot) with benzyladenine (0.4, 0.6, 0.8 or 1.0 mmol) and placed into plastic trays, without sleeve. The experimental design was a randomized blocks with 6 treatments (control, four benzyladenine concentrations and senescent flowers removal), 4 replications (2 pots per experimental unit), totalising 12 potted plants in each plastic tray (block). To simulate highway transport, plants remained for 4 days in a dark chamber, at 20.0 °C without irrigation. To include vibration, each plastic tray, was placed in an incubator shaker for 3hr a day, at 60 rpm, 25°C and darkness. After simulated transport, plants remained indoors (10h.day-1 with 18 μmol.m-2.s-1 PPF, 21.5 to 27.0°C and, 14 h.day-1 at darkness, 18.5 to 24.0°C) during 21 days. Plants performed well during simulated transport, and also indoors for two weeks. For most of evaluated parameters there was not significant effect of benzyladenine concentrations by Tukey's test. Senescent flowers removal did not delayed senescence or improved plants quality. The symptoms associated with the loss of decorative life were ray florets color fading and wilting, without abscission of flowers or petals.

Efeitos de parâmetros de extrusão nas propriedades físicas de produtos expandidos de inhame

Effect of extrusion parameters was studied on the expansion index, specific volume, water absorption index (WAI) and water solubility index (WSI) of expanded yam snacks. The central composite design was used to study the parameters effect. It was verified three levels of temperature in the barrel (100, 115 and 130°C), three levels of screw speed (163, 204 and 245 rpm) and three levels of flour moisture (12, 15 and 18%). The results showed that expansion properties (expansion index and specific volume) depend on flour moisture and extrusion temperature. The WSI was dependant of three parameters. Higher levels of temperature and screw speed increase the water solubility index (WSI). The studied parameters did not influence the water absorption index (WAI).

Influence of the tool edge geometry on specific cutting energy at high-speed cutting

This paper presents specific cutting energy measurements as a function of the cutting speed and tool cutting edge geometry. The experimental work was carried out on a vertical CNC machining center with 7,500 rpm spindle rotation and 7.5 kW power. Hardened steels ASTM H13 (50 HRC) were machined at conventional cutting speed and high-speed cutting (HSC). TiN coated carbides with seven different geometries of chip breaker were applied on dry tests. A special milling tool holder with only one cutting edge was developed and the machining forces needed to calculate the specific cutting energy were recorded using a piezoelectric 4-component dynamometer. Workpiece roughness and chip formation process were also evaluated. The results showed that the specific cutting energy decreased 15.5% when cutting speed was increased up to 700%. An increase of 1 °in tool chip breaker chamfer angle lead to a reduction in the specific cutting energy about 13.7% and 28.6% when machining at HSC and conventional cutting speed respectively. Furthermore the workpiece roughness values evaluated in all test conditions were very low, closer to those of typical grinding operations (∼0.20 μm). Probable adiabatic shear occurred on chip segmentation at HSC Copyright © 2007 by ABCM.

Análise dos parâmetros cinéticos para produção de levana por Zymomonas mobilis utilizando fermentação submersa

Levan is an exopolysaccharide synthesized by several microorganisms during fermentation of a culture medium containing sucrose, yeast extract and minerals. This biopolymer has applications in the food segment as stabilizers, thickeners, as carriers for flavor and fragrances, as well as in the pharmaceutical segment as a hypocholesterolemic agent and for exhibiting antitumor activity. This work aimed to analyze the kinetic parameters for levan production. The microorganism used was Zymomonas mobilis CCT 4494, incubated in a synthetic medium containing 200.0 g L-1 of sucrose, in a rotary shaker at 200 rpm and 30°C. Samples were taken every 24h, during a period of 96h, in order to determine variations of pH, biomass, reducing sugar, total reducing sugar and levan formation. It was observed that yields of biomass and synthesized biopolymer in 24h were superior to those obtained in 48, 72 and 96h of fermentation.

Use of soybean oil fry waste for economical biosurfactant production by isolated Pseudomonas aeruginosa using response surface methodology

The present study sought biotensoactive production from soybean oil fry waste using Pseudomonas aeruginosa ATCC 10145 and Pseudomonas aeruginosa isolated from the soil of a petroleum station having undergone gasoline and diesel oil spills. The results of the experiments were analyzed using a complete factorial experimental design, investigating the concentration of soybean oil waste, ammonia sulfate and residual brewery yeast. Assays were performed in 250-mL Erlenmeyer beakers containing 50 mL of production medium, maintained on a rotary shaker at 200 rpm and a temperature of 30±1 °C for a 48-hour fermentation period. Biosurfactant production was monitored through the determination of rhamnose, surface tension and emulsification activity. The Pseudomonas aeruginosa ATCC 10145 strain and isolated Pseudomonas aeruginosa were able to reduce the surface tension of the initial mexlium from 61 mN/m to 32.5 mN/m and 30.0 mN/m as well as produce rhamnose at concentrations of 1.96 and 2.89 g/L with emulsification indices of 96% and 100%, respectively.

Estado físico do meio de cultura na propagação in vitro de bromeliaceae

The objective of this study was to evaluate the effect of the physical state of the culture medium on the behavior in vitro of the bromeliaceas Neoregelia cruenta, Tillandsia stricta, Vriesea gigantea, V. guttata e V. incun/ata. Micropropagated shoots had been cultivated in culture medium MS, with 30 g sucrose, 2,5 mg dm-3 BAP, and 0,5 mg dm-3 ANA, establishing the treatments: T1- half-solid with 7 g agar; T2- static liquid; T3- liquid under-agitation of 90 rpm; and T4-static liquid with bridge of paper filter. After 30 days, the use of static way of liquid culture presented better results in relation of proliferative average rate in all the species (9.4 shoots in N. cruenta, 5.6 in T. stricta, 11.5 in V. gigantea, 9.2 in V. guttata and 3.9 in V. incurvata). In relation the average height of the shoots, was distinguished for N. cruenta the liquid under-agitation (2.83 cm), T. stricta and V. incurvata the semisolid (1.76 cm and 2.02 cm, respectively) and V. gigantea and V. guttata the static liquid (0.61 cm and 1.48 cm, respectively). The use of medium MS static liquid was more suitable for in vitro culture of bromeliads species studied.

Cyclodextrin glycosyltransferase production by the Bacillus sp., subgroup alcalophilus using a central composite design

Cyclodextrin glycosyltransferase (CGTase) activity was produced by the Bacillus sp., subgroup alcalophilus in a culture medium containing cassava starch. A central composite design and response surface methodology were used to study the influence of carbon source (cassava starch), nitrogen sources (yeast extract and tryptone) and sodium carbonate in the production medium. Assays were performed in 300 mL Erlenmeyer flasks containing 100 mL of production medium maintained in a shaker at 150 rpm at 35±1°C for 72 h of fermentation. The independent variables [0.75% cassava starch, nitrogen sources (0.375% yeast extract and 0.375% tryptone) and 1% Na2CO3] produced an enzyme activity of 96.07 U mL-1.© Academic Journals Inc.

Keratinase production by new strain of Bacillus Amyloliquefaciens: Application of statistical experimental design for optimization of keratinase production

Feathers are rich in amino acids and can be employed as a dietary protein supplement for animal feed. Microbial degradation is an alternative technology for improving the nutritional value of feathers. Other potential applications of keratinase include use in the leather industry, detergents and medicine as well as the pharmaceutical for the treatment of acne, psoriasis and calluses. A new keratinolytic enzyme production bacterium was isolated from a poultry processing plant. To improve keratinase yield, statistically based experimental designs were applied to optimize three significant variables: temperature, substrate concentration (feathers) and agitation speed. Response surface methodology demonstrated an increase in keratinolytic activity at temperature, agitation speed and substrate concentration of 26.6°C, 150 rpm and 2%, respectively. Liquid chromatography revealed the release of amino acids in the Bacillus amyloliquefaciens culture broth, thereby demonstrating the potential of feather meal in the animal feed industry. © Global Science Publications.