RESUMEN

Xylanases have gained increasing importance due to their diverse applications in the food, paper, and pharmaceutical industries, however, the production of these enzymes currently uses expensive substrates. It has already been estimated that more than 30% of the enzyme production cost originates from the substrate. The present study aimed to optimize the production of extracellular xylanases by the Bacillus sp. TC-DT 13 using solid-state fermentation with agro-industrial residues, with a view at reducing the production cost of these enzymes. All the agro-industrial residues were tested in submerged fermentation to select the best inductor to produce xylanase. Among these residues, wheat bran was selected as the best inducer of xylanase production with 1500 U/mL. Regarding solid-state fermentation, the use of wheat bran as the only fermentation substrate was used and a ratio of 1:4 moisture over a time of 144 hours induced higher amount of xylanase reaching 2943 U/g. The use of carbon and nitrogen sources did not result in the increase in production of xylanolitic enzymes. The use of agro-industrial residues in the solid-state fermentation, besides increasing the production of xylanase, reduces the cost of production and is an environmentally friendly alternative.

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In this study, two hundred fifty-seven bacterial isolates from a suppressive soil library were screened to study their secretion of alkali-thermostable xylanases for potential use in cellulose pulp biobleaching. Xylanase activity was evaluated in solid and liquid media using xylan as the carbon source. Isolates were initially evaluated for the degradation of xylan in solid media by the congo red test. Selected strains were evaluated in liquid media for enzymatic activity and determination of total protein concentration using a crude protein extract (CPE). An isolate identified as Bacillus species TC-DT13 produced the highest amount of xylanase (1808 U mL-1). The isolate was active and stable at 70°C and pH 9.0, conditions which are necessary for the paper industry. This isolate can grow and produce xylanase in medium containing wheat fiber as a substrate. The CPE of this isolate was used in preliminary testing on cellulose pulp bleaching; enzyme treatment of the pulp resulted in a 5% increase of whiteness.

Asunto(s)

RESUMEN

In this study, two hundred fifty-seven bacterial isolates from a suppressive soil library were screened to study their secretion of alkali-thermostable xylanases for potential use in cellulose pulp biobleaching. Xylanase activity was evaluated in solid and liquid media using xylan as the carbon source. Isolates were initially evaluated for the degradation of xylan in solid media by the congo red test. Selected strains were evaluated in liquid media for enzymatic activity and determination of total protein concentration using a crude protein extract (CPE). An isolate identified as Bacillus species TC-DT13 produced the highest amount of xylanase (1808 U mL-1). The isolate was active and stable at 70°C and pH 9.0, conditions which are necessary for the paper industry. This isolate can grow and produce xylanase in medium containing wheat fiber as a substrate. The CPE of this isolate was used in preliminary testing on cellulose pulp bleaching; enzyme treatment of the pulp resulted in a 5% increase of whiteness.(AU)

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Objetivou-se nesse trabalho identificar herbicidas utilizados na cultura da cana-de-açúcar que não afetam o crescimento, o desenvolvimento, ou que não causem prejuízos à capacidade de fixação biológica de nitrogênio (FBN) da bactéria diazotrófica Herbaspirillum seropedicae. Dezoito herbicidas (paraquat, ametryne, tebuthiuron, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron sodium + ametryne], glyphosate, MSMA e 2,4-D) foram testados em suas respectivas doses comerciais quanto ao impacto sobre os parâmetros de crescimento da bactéria em meio líquido DIGs. Os parâmetros analisados foram a duração da fase lag, tempo de geração e densidade celular máxima, calculados a partir de dados de densidade ótica obtidos, em intervalos regulares, durante a incubação de culturas por 33 h, a 32oC. Também foi avaliado o impacto dos herbicidas na atividade da nitrogenase de H. seropedicae cultivada em meio semi-sólido JNFb livre de N. Os efeitos dos herbicidas sobre os parâmetros de crescimento e sobre a atividade de redução do acetileno (ARA) foram comparados ao tratamento controle pelo teste de Dunnett, sendo utilizado o delineamento inteiramente casualizado. Os herbicidas paraquat, imazapyr, ametryne, glyphosate e oxyfluorfen inibiram o crescimento de H. seropedicae in vitro. Os herbicidas ametryne, oxyfluorfen e glyphosate ocasionaram pequena reduçãona duração da fase lag da bactéria diazotrófica H. seropedicae. Os herbicidas oxyfluorfen, ametryne e imazapyr acarretaram aumento no tempo de geração de H. seropedicae. O herbicida glyphosatepromoveu redução drástica na fixação biológica de nitrogênio in vitro de H. seropedicae. Os demais herbicidas avaliados não afetaram os parâmetros de crescimento ou mesmos a FBN de H. seropedicae.(AU)

The objective of this work was to identify herbicides used in the sugarcane crop that affects neither the growth, the development, of nor the process of biological nitrogen fixation (BNF) by the diazotrophic bacterium Herbaspirillum seropedicae. Eighteen herbicides (paraquat, ametryne, tebuthiuron, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron sodium + ametryne],glyphosate, MSMA e 2,4-D) were tested in their respective commercial doses regarding their impact on the growth of the bacteria in liquid medium DIGs. For this, we determined the duration of lag phase, generation time and maximum cell density of H. seropedicae, calculated from optical density data obtained at regular intervals during the incubation of cultures for 33 h at 32o C. We also evaluated the impact of herbicides on nitrogenase activity of H. seropedicae grown in semi-solid N-free JNFb medium.The effects of herbicides on the growth variables and the ARA were compared with the untreated control by Dunnett test. A completely randomized design was used. The herbicides paraquat, imazapyr, ametryne, glyphosate and oxyfluorfen inhibited the growth of H. seropedicae in vitro. Ametryne, oxyfluorfen and glyphosate caused a small reduction in the duration of the lag phase of diazotrophic bacteria H. seropedicae. Oxyfluorfen, ametryne and imazapyr resulted in increased the generation time by H. seropedicae. Glyphosate promoted drastic reduction in biological nitrogen fixation in vitro by H. seropedicae. The other tested herbicides did not affect the growth or the same BNF by H. seropedicae.(AU)

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Fatty acids, especially those from phospholipids (PLFA), are essential membrane components that are present in relatively constant proportions in biological membranes under natural conditions. However, under harmful growth conditions, such as diseases, environmental changes, and chemical exposure, the fatty acid proportions might vary. If such changes could be identified and revealed to be specific for adverse situations, they could be used as biomarkers. Such biomarkers could facilitate the identification of virulence and resistance mechanisms to particular chemotherapeutic agents. Therefore, specific biomarkers could lead to better therapeutic decisions that would, in turn, enhance treatment effectiveness. The objective of this study was to compare the fatty acid profiles of trivalent antimony and nitric oxide (NO)-resistant and -sensitive Leishmania chagasi and Leishmania amazonensis isolates. Fatty acid methyl esters (FAMEs) were obtained from total lipids (MIDI), ester-linked lipids (ELFA), and ester-linked phospholipids (PLFA). FAMEs were analyzed by chromatography and mass spectrometry. Species- or resistance-associated differences in FAME profiles were assessed by nonmetric multidimensional scaling, multiresponse permutation procedures, and indicator species analyses. The isolate groups had different MIDI-FAME profiles. However, neither the ELFA nor PLFA profiles differed between the sensitive and resistant isolates. Levels of the fatty acid 18:1 Δ9c were increased in sensitive isolates (p < 0,001), whereas the fatty acid 20:4 Δ5,8,11,14 showed the opposite trend (p < 0.01). We conclude that these two fatty acids are potential biomarkers for NO and antimony resistance in L. chagasi and L. amazonensis and that they could be helpful in therapeutic diagnoses.

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Objetivou-se nesse trabalho identificar herbicidas utilizados na cultura da cana-de-açúcar que não afetam o crescimento, o desenvolvimento, ou que não causem prejuízos à capacidade de fixação biológica de nitrogênio (FBN) da bactéria diazotrófica Herbaspirillum seropedicae. Dezoito herbicidas (paraquat, ametryne, tebuthiuron, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron sodium + ametryne], glyphosate, MSMA e 2,4-D) foram testados em suas respectivas doses comerciais quanto ao impacto sobre os parâmetros de crescimento da bactéria em meio líquido DIGs. Os parâmetros analisados foram a duração da fase lag, tempo de geração e densidade celular máxima, calculados a partir de dados de densidade ótica obtidos, em intervalos regulares, durante a incubação de culturas por 33 h, a 32oC. Também foi avaliado o impacto dos herbicidas na atividade da nitrogenase de H. seropedicae cultivada em meio semi-sólido JNFb livre de N. Os efeitos dos herbicidas sobre os parâmetros de crescimento e sobre a atividade de redução do acetileno (ARA) foram comparados ao tratamento controle pelo teste de Dunnett, sendo utilizado o delineamento inteiramente casualizado. Os herbicidas paraquat, imazapyr, ametryne, glyphosate e oxyfluorfen inibiram o crescimento de H. seropedicae in vitro. Os herbicidas ametryne, oxyfluorfen e glyphosate ocasionaram pequena reduçãona duração da fase lag da bactéria diazotrófica H. seropedicae. Os herbicidas oxyfluorfen, ametryne e imazapyr acarretaram aumento no tempo de geração de H. seropedicae. O herbicida glyphosatepromoveu redução drástica na fixação biológica de nitrogênio in vitro de H. seropedicae. Os demais herbicidas avaliados não afetaram os parâmetros de crescimento ou mesmos a FBN de H. seropedicae.

The objective of this work was to identify herbicides used in the sugarcane crop that affects neither the growth, the development, of nor the process of biological nitrogen fixation (BNF) by the diazotrophic bacterium Herbaspirillum seropedicae. Eighteen herbicides (paraquat, ametryne, tebuthiuron, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron sodium + ametryne],glyphosate, MSMA e 2,4-D) were tested in their respective commercial doses regarding their impact on the growth of the bacteria in liquid medium DIGs. For this, we determined the duration of lag phase, generation time and maximum cell density of H. seropedicae, calculated from optical density data obtained at regular intervals during the incubation of cultures for 33 h at 32o C. We also evaluated the impact of herbicides on nitrogenase activity of H. seropedicae grown in semi-solid N-free JNFb medium.The effects of herbicides on the growth variables and the ARA were compared with the untreated control by Dunnett test. A completely randomized design was used. The herbicides paraquat, imazapyr, ametryne, glyphosate and oxyfluorfen inhibited the growth of H. seropedicae in vitro. Ametryne, oxyfluorfen and glyphosate caused a small reduction in the duration of the lag phase of diazotrophic bacteria H. seropedicae. Oxyfluorfen, ametryne and imazapyr resulted in increased the generation time by H. seropedicae. Glyphosate promoted drastic reduction in biological nitrogen fixation in vitro by H. seropedicae. The other tested herbicides did not affect the growth or the same BNF by H. seropedicae.

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Objetivou-se com esta pesquisa avaliar a possibilidade da inclusão dos óleos de Licuri ou Mamona, em dois níveis, na dieta de cabras mestiças Moxotó, por meio do estudo do consumo de matéria seca, da digestibilidade e dos níveis de ureia, glicose e ácidos graxos não esterificados (AGNE) no sangue. Os tratamentos consistiam em um grupo controle sem óleo (SO) e adição de 3 ou 5 por cento de óleo de Licuri (OL-3 ou OL-5) ou Mamona (OM-3 ou OM-5), com base na matéria seca. Foram utilizadas 10 cabras mestiças Moxotó em lactação, confinadas, distribuídas em um quadrado latino duplo (5 x 5), no qual cada período consistia em 12 dias de adaptação e três dias de coleta. A inclusão de óleo na dieta reduziu o consumo de matéria seca, com exceção do consumo dos animais suplementados com OM-3. No entanto, a adição de 3 por cento de óleo não alterou o consumo de energia metabolizável e proteína bruta. Já a suplementação com OL-5 reduziu o consumo dos nutrientes, com exceção do consumo de extrato etéreo. A suplementação lipídica não alterou a digestibilidade da matéria seca, entretanto aumentou a digestibilidade da FDN e a digestibilidade aparente da PB e EE. Os níveis de glicose, ureia e AGNE sanguíneos não diferiram entre os tratamentos. É possível utilizar 3 por cento de óleo de Mamona na dieta de cabras em lactação.

The objective of this research was to evaluate the possibility of including Castor or Licuri oil at two levels in the diets of crossbred Moxotó goat's through dry matter intake, digestibility and levels of urea, glucose and nonesterified fatty acids (NEFA) in the blood. The treatments consisted of control groups without oil, 3 percent or 5 percent of Licuri (LO-3 or LO-5) or Castor (CO-3 or CO-5) oil, based on dry matter supplementation. Ten Moxotó lactating goats were used according to a double Latin Square (5 x 5) experiment design. The addition of oil to the diet reduced the dry matter intake, except for animals that were supplemented with CO-3. However, the addition of 3 percent of oil didn´t alter the intake of metabolizable energy and crude protein. The animals supplemented with LO-5 oil showed smaller nutrients intake, except for ether extract intake. The lipid supplement didn´t alter the dry matter digestibility, however increased the NDF digestibility the CP and EE apparent digestibility. There was no difference among the glucose levels, urea and NEFA in the blood. It is possible to use 3 percentCastor oil in the diet of lactating goats.