O uso de enzimas no processamento de alimentos, detergente e no setor têxtil está em constante ascensão. A aplicação de enzimas proteolíticas de origem microbiana se destaca no setor industrial devido as condições desejáveis para uso em processos biotecnológicos, são biocatalisadores naturais e não tóxicos. O objetivo dessa pesquisa foi avaliar a produção e caracterizar as proteases sintetizadas por Aspergillus flavus. A cultura matriz foi preparada em ágar Sabouraud e mantida por sete dias a 25 ºC. Em seguida, a espécie foi cultivada em meio líquido [GYP (glicose, extrato de levedura e peptona)]. A fermentação foi conduzida em agitador orbital 150 rpm, 25 ºC. Após oito dias a massa micelial foi separada por filtração a vácuo em papel Whatman nº 1 e o extrato bruto recuperado, e filtrado em membrana polietersulfônica de 0,45μL. Para determinação da atividade das proteases foi utilizado como substrato azocaseína 1% (p/v) em tampão Tris-HCl pH 7.2. Os resultados mostraram que A. flavus excretou proteases em todos nos meios testados, porém com atividade significativa no meio GYP (90,13 U/mL). As proteases apresentaram atividade ótima em pH 5 e temperatura 50ºC. Esses resultados sugerem que essas enzimas podem ser utilizadas em diversos segmentos industriais, como alimentícia, têxtil e panificação.
Fiber of Urena lobata L. (Caesar weed or Malva) has been produced from plants cultivated in floodplain areas of Brazilian Amazonas state since 1970s. Plants must be harvested before flooding and because of such a short cultivation season plants never reach fructification. Thus, local farmers depend on acquiring seeds collected in areas of spontaneous occurrence in drylands to sow their crop fields each year. This scenario might change, as this species is gaining socioeconomic important and there is interest in the development of cropping systems for seed production on a commercial scale. The objective of this study was to investigate the occurrence of endophytic fungi in U. lobata, evaluating the influence of the plant organ (leaf and seed) and farming site (two experimental fields of seed production: Manaus and Anori municipalities), once endophytic interaction can be beneficial or become harmful to the plants. The frequency and degree of colonization, Shannon-Weaver and Simpson diversity and Pielou uniformity indexes and the dominance component curve were calculated. The occurring genus were: Phomopsis, Colletotrichum, Fusarium, Pestalotiopsis, Curvularia and Cochliobolus. The greatest diversity and richness of fungi was found in Manaus site with high colonization present in the leaves. The genus Curvularia and Fusarium presented preference for seeds while Colletotrichum was more frequent in leaves. The similarity was greater between plant organs than between the farming sites, which indicates that the coevolution of these fungi and its host has resulted in a balanced mutual or antagonistic interaction (Crane & Acuna, 1945; Souza, 2012).
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