Fluoranthene Biodegradation by Serratia sp. AC-11 Immobilized into Chitosan Beads.

The intensive production of polycyclic aromatic hydrocarbons by anthropogenic activities is a serious environmental problem. Therefore, new bioremediation methods are required to avoid widespread contamination. In this work, Serratia sp. AC-11 strain isolated from a tropical peat was selected for immobilization into chitosan beads, which were employed in the biodegradation of fluoranthene. The sizes of the produced beads were relatively uniform with an average diameter of 3 mm. The material was characterized by SEM and FT-IR, confirming the cells immobilization and the protective barrier formed by the chitosan surrounding the biomass. The immobilized bacteria were able to degrade 56% of fluoranthene (the initial concentration was 100 mg L-1) in just 1 day at twice the degradation rate achieved by free-living cells. Furthermore, the immobilized bacteria showed excellent removal during five reuse cycles, from 76% to 59% of biodegradation. These results showed the potential of this approach for remediation of contaminated sites.

Application of termite nest for adsorption of Cr(VI).

This work proposes the use of tree termite nest as an adsorbent for the reduction/removal of Cr(VI) present in aqueous solution. In laboratory experiments, adsorption of Cr(VI) was sensitive to pH in the range investigated (2-5), with maximum adsorption capacity achieved at pH 2 (3.70 ± 0.04 mg g(-1), representing 93.2% removal of Cr). The termite nest was characterized by off-line pyrolysis GC/MS (py-GC/MS), infrared spectroscopy (FTIR), and electron paramagnetic resonance spectroscopy (EPR). Pyrolysis of the adsorbent produced a complex mixture of aromatic compounds, including the guaiacyl and syringilic derivatives that are characteristic of lignocellulosic materials. Infrared spectroscopy revealed deprotonation of the carboxylic acid group of the biomass with increasing pH, which was associated with a decrease in the capacity for adsorption of Cr(VI). The EPR g-factor for the termite nest samples varied between 2.0037 and 2.0038, indicating the presence of organic free radicals that were responsible for the redox reaction. A second line with g-factor values of 1.9790, only observed for the samples after contact with Cr(VI) solutions at different pH values, was assigned to Cr(III)-Cr(III) exchange coupled pairs, which explained the capacity of the adsorbent to retain a large portion of the Cr(III) ions produced after reduction of Cr(VI) to Cr(III). Fixed-bed column experiments showed that the termite nest had a maximum adsorption capacity of 18.60 mg Cr g(-1), an adsorption efficiency varying between 60.8 and 97.4%, and a desorption efficiency varying between 54.5 and 91.4%, for three successive cycles. The adsorbent presented excellent performance in the removal of chromium under acidic conditions, with the advantage that it could be regenerated and reused.

Environmental strategies to remove volatile aromatic fractions (BTEX) from petroleum industry wastewater using biomass.

This work investigates the potentials of peat and angico hardwood sawdust to remove BTEX (benzene, toluene, ethylbenzene, and isomers of xylene) from the produced water discharged into aquatic systems during petroleum extraction. Peat and angico sawdust samples were pyrolyzed at 500°C, and found to contain n-alkenes, n-alkanes and pentacyclic triterpenes (peat), and 4-methoxyphenol, 1,4-dimethoxyphenol and 1,3,4-trimethoxyphenol (angico sawdust). In batch experiments, the removal capacities using peat were 32.4%, 50.0%, 63.0%, 67.8%, and 61.8% for benzene, toluene, ethylbenzene, m,p-xylenes and o-xylene, respectively. This compared with removal capacities using angico sawdust of 20.2%, 36.4%, 52.8%, 57.8%, and 53.7% for these compounds respectively, demonstrating the superior performance of the peat.

Inquérito soro-epidemiológico de Brucella ovis em rebanhos ovinos no semiárido baiano / Sero-erpidemiological survey for Brucella ovis infection in sheeo flocks of Bahia state, Brazil

Com o objetivo de analisar a ocorrência de anticorpos contra Brucella ovis em ovinos no semiárido baiano, este inquérito foi conduzido em rebanhos da microrregião de Juazeiro, Bahia. O teste de imunodifusão em gel de ágar (IDGA) foi utilizado para examinar 694 amostras de soro de 58 rebanhos. Anticorpos para B. ovis foram observados em cinco (0,72%) dos animais investigados. Acredita-se que o baixo número de soropositivos deva-se às características dos sistemas de produção, com predominância do tipo de exploração extensiva de animais localmente adaptados, mestiços e sem raça definida para a produção de carne e pele, com baixa produtividade e tecnificação.(AU)

In order to analyze the occurrence of antibodies to Brucella ovis in sheep in a semi-arid region, this survey was conducted in the micro-region of Juazeiro, Bahia State, Brazil. The agar gel immunodifusion test (AGID) was used to examine 694 serum samples of 58 flocks. Antibodies to B. ovis were found in 5 (0.72%) of the investigated animals. It is believed that this low number of positive cases is related to the characteristics of the production. The predominant system is the extensive one, with presence of locally adapted breeds and crossbred animals, aiming at the production of meat and skin, with low productivity rates and technical development.(AU)

Inquérito soro-epidemiológico de Brucella ovis em rebanhos ovinos no semiárido baiano

In order to analyze the occurrence of antibodies to Brucella ovis in sheep in a semi-arid region, this survey was conducted in the micro-region of Juazeiro, Bahia State, Brazil. The agar gel immunodifusion test (AGID) was used to examine 694 serum samples of 58 flocks. Antibodies to B. ovis were found in 5 (0.72%) of the investigated animals. It is believed that this low number of positive cases is related to the characteristics of the production. The predominant system is the extensive one, with presence of locally adapted breeds and crossbred animals, aiming at the production of meat and skin, with low productivity rates and technical development.

Com o objetivo de analisar a ocorrência de anticorpos contra Brucella ovis em ovinos no semiárido baiano, este inquérito foi conduzido em rebanhos da microrregião de Juazeiro, Bahia. O teste de imunodifusão em gel de ágar (IDGA) foi utilizado para examinar 694 amostras de soro de 58 rebanhos. Anticorpos para B. ovis foram observados em cinco (0,72%) dos animais investigados. Acredita-se que o baixo número de soropositivos deva-se às características dos sistemas de produção, com predominância do tipo de exploração extensiva de animais localmente adaptados, mestiços e sem raça definida para a produção de carne e pele, com baixa produtividade e tecnificação.

Inquérito soro-epidemiológico de Brucella ovis em rebanhos ovinos no semiárido baiano / Sero-erpidemiological survey for Brucella ovis infection in sheeo flocks of Bahia state, Brazil

Com o objetivo de analisar a ocorrência de anticorpos contra Brucella ovis em ovinos no semiárido baiano, este inquérito foi conduzido em rebanhos da microrregião de Juazeiro, Bahia. O teste de imunodifusão em gel de ágar (IDGA) foi utilizado para examinar 694 amostras de soro de 58 rebanhos. Anticorpos para B. ovis foram observados em cinco (0,72%) dos animais investigados. Acredita-se que o baixo número de soropositivos deva-se às características dos sistemas de produção, com predominância do tipo de exploração extensiva de animais localmente adaptados, mestiços e sem raça definida para a produção de carne e pele, com baixa produtividade e tecnificação.

In order to analyze the occurrence of antibodies to Brucella ovis in sheep in a semi-arid region, this survey was conducted in the micro-region of Juazeiro, Bahia State, Brazil. The agar gel immunodifusion test (AGID) was used to examine 694 serum samples of 58 flocks. Antibodies to B. ovis were found in 5 (0.72%) of the investigated animals. It is believed that this low number of positive cases is related to the characteristics of the production. The predominant system is the extensive one, with presence of locally adapted breeds and crossbred animals, aiming at the production of meat and skin, with low productivity rates and technical development.

Adsorption of trihalomethanes by humin: Batch and fixed bed column studies.

The objective of the present work was to assess the performance of batch and fixed bed column systems, using humin in natura and immobilized on sodium silicate, respectively, for the adsorption of the principal trihalomethanes (THMs) found in water supply systems. Kinetically, adsorption of THMs by humin follows a pseudo-second order reaction, with more than 50% removal in the first 5min for all compounds studied, and equilibrium described by the Freundlich model reached in 240min. The THM adsorption results were significant at p<0.05 for both batch (74.6-83.2% removal) and column (99.7% removal in optimized tests) experiments, and were significantly (p<0.05) influenced by flow rate and bed height. The work demonstrates the potential of humin for removal of THMs.