Screening of bacterial extracellular xylanase producers with potential for cellulose pulp biobleaching

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.

Phenolic Composition and Leishmanicidal Activity of Red Propolis and Dalbergia ecastaphyllum (L.) Taub (Fabaceae) Extracts from Sergipe, Brazil

ABSTRACT Leishmaniasis is a parasitic disease caused by protozoa of the Leishmania genus. It may manifest in visceral and tegumentary forms, and pentavalent antimonials are the first choice drugs used for the treatment. Frequently these drugs show low efficiency and high toxicity to mammalian host. The present study describes the chemical profile and the in vitro leishmanicidal effects of red propolis and Dalbergia ecastaphyllum extracts from Sergipe, Brazil, in Leishmania chagasi and Leishmania amazonensis promastigotes. The phenolic composition of the extracts was evaluated by direct infusion electrospray ionization mass spectrometry (ESI-MS) fingerprinting. The leishmanicidal effect was evaluated by the Resazurin colorimetric method. Similar composition profiles have been found for D. ecastaphyllum and propolis samples. The isoflavones formononetin, biochanin A, daidzein and pinocembrin were identified in both extracts. Propolis extract showed leishmanicidal activity in both L. chagasi and L. amazonensis, with IC50 values of 21.54 and 9.73 µg/mL, respectively. The D. ecastaphyllum extract presented activity only in L. amazonensis, with IC50 of 53.42 µg/mL. These results suggest that red propolis extract from Sergipe has the leguminosae D. ecastaphyllum as botanical origin, and that it presents potential leishmanicidal activity, which may be associated with the presence of the phenolic compounds found in its composition.

Performance of sweet potato clones for starch and ethanol in three regions of the state of Sergipe, Brazil / Desempenho de clones de batata doce para amido e etanol em três regiões do estado de Sergipe, Brasil

Sweet potato (Ipomoea batatas L.) is a species that belongs to the family Convolvulaceae, and is originated from Central America and South America. As the growing conditions have great influence on the crop, the determination of harvesting time may vary with the cultivar, the growing region, or with the type of consumption (in natura or industrial). The aim of this work was to evaluate the performance of Ipomoea batatas L. clones, cultivated in three regions in the state of Sergipe, for starch and ethanol production. Thirty-one sweet potato clones grown in three municipalities of the state of Sergipe were tested in a randomized block design. The following variables were analyzed: root dry matter content (RDMC), root starch content (SC), starch yield (SY), ethanol yield (EY), and ethanol yield per ton of root (EYR). EY values ranged from 5910.39 to 8516.12 L ha-1; from 5141.85 to 6937.63 L ha-1; and from 5829.62 to 8211.77 L ha-1 in the municipalities of São Cristóvão, Malhador, and Canindé de São Francisco, respectively, for clones IPB-075 and IPB-087 and cultivar Palmas. Estimates of heritability (h2) were above 50%. The values of the ratio between the coefficient of genetic variation (CVg) and the coefficient of environmental variation (CVe) for RDMC, SC, and EYR were high.

A batata doce é uma espécie pertencente a família Convolvulaceae, originária da América Central e do Sul. As condições de cultivo têm grande influência na produção, sendo que a determinação do tempo de colheita varia de acordo com a cultivar, com a região de cultivo e com a forma de consumo (in natura ou industrial). O objetivo deste trabalho foi avaliar o desempenho de clones de batata-doce (Ipomoea batatas L.) cultivados em três regiões do estado de Sergipe para produção de amido e etanol. Testou-se, em delineamento de blocos casualizados, 31 genótipos de batata doce em três município do Estado de Sergipe. As características analisadas foram: teor de matéria seca de raízes (RDMC), teor de amido nas raízes (SC), rendimento de raízes (SY), rendimento de etanol (EY) e rendimento de etanol por tonelada de raiz (EYR). Os valores de EY variaram de 5910,39 a 8516,12 L.ha-1, de 5141,85 a 6937,63 L ha-1 e de 5829,62 a 8211,77 L ha-1 para São Cristóvão, Malhador e Canindé de São Francisco, respectivamente, para os clones IPB-075 e IPB-087 e a cultivar Palmas. As estimativas de herdabilidade (h2) foram superiores a 50 %. Os valores da razão entre o coeficiente de variação genotípica e o ambiental para RDMC, SC, e EYR foram altos.

Cytokinin Dehydrogenase activity in primary roots and characterization of primary metabolites from leaves and rootlets of Ricinus Communis

The aim of this study was to determine the activity of cytokinin dehydrogenase (CKX) and to measure other biochemical components in the primary leaves and radicles of castor seedlings (BRS Energia) in the initial phase of growth. The crude protein extract obtained after a 1-h extraction from the root tissues of seedlings showed no detectable CKX enzymatic activity when incubated with the substrate isopentenyl adenine for 1 h. However, after precipitation with ammonium sulfate at 70% saturation, the pellet showed CKX activity. The peroxidase enzyme activity was higher in the leaves than in the radicles. The total and reducing sugar content was 1.5 times higher in the leaves than in the radicles. The amino acid and protein contents were 6.4 and 9.2 times higher in the leaves than in the radicles, respectively.