Cellulose nanofibers produced from banana peel by chemical and enzymatic treatments: characterization and in vitro cytotoxicity assessment

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Cellulose nanofibers produced from banana peel by enzymatic treatment: study of process conditions

Cellulose nanofibers (CNFs) were isolated from banana peel bran via alkaline treatment followed by enzymatic treatment with xylanase. The influence of process conditions such as pH, temperature, and concentrations of the enzyme and substrate on the properties of the CNFs was evaluated with a 24−1 fractional factorial design with three central points. Enzyme at 70 U/g of bran, substrate at 15%, pH 6.0, and temperature between 35 and 55 °C favored enzymatic hydrolysis. Transmission electron microscopy (TEM) images confirmed that treatment with xylanase effectively isolated cellulose fibers at the nanometer scale. Fourier transform infrared spectroscopy (FTIR) showed that a fraction of amorphous compounds was removed. X-ray diffraction revealed that the CNFs presented high crystallinity index (66.2%). The CNFs had a diameter of 3.7 nm, their aspect ratio was in the range of long nanofibers, and their suspension was stable (−29.1 mV). These features make the CNFs potentially applicable as reinforcing agents in composites. The results evidenced that enzymatic hydrolysis with xylanase successfully afforded CNFs from banana peel, a residue that constitutes a potential source of biodegradable materials of commercial interest95664674CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES477842/2011-92952/201

Características químicas de solo cultivado com soja e irrigado com água residuária da suinocultura Chemical characteristics of the soil cultivated with soybean and irrigated with swine wastewater

Neste trabalho se avaliou a distribuição "in situ" de fósforo (P), matéria orgânica (MO), potássio (K), cálcio (Ca), magnésio (Mg), capacidade de troca catiônica (T), alumínio (Al), soma de bases (S), saturação por bases (V) e do pH, em um solo cultivado com soja irrigada com água residuária proveniente da suinocultura (ARS), com níveis de concentração de 0, 25, 50 e 75%. Constituiu-se um esquema fatorial a partir dos quatros níveis de concentração da ARS, das profundidades de 20, 40 e 60 cm com cinco repetições. Os resultados encontrados demonstraram diferenças significativas apenas para P, K e T no perfil do solo. Para todas as características na profundidade de 60 cm, os respectivos níveis de concentração estiveram bastante próximos aos níveis iniciais, ou seja, antes da aplicação dos tratamentos.<br>In this work the distribution was evaluated "in situ" of phosphorus (P), organic matter (MO), potassium (K), calcium (Ca), magnesium (Mg), cation exchange capacity (CEC), aluminum (Al), sum of bases (S), base saturation (V) and pH of a soil cultivated with soybean and irrigated with swine wastewater in the 0, 25, 50 and 75% levels. The factorial scheme was constituted by the 20, 40 and 60 cm soil depths and four wastewater levels with five repetitions. The results showed that significant difference occurred only for P, K and CEC in the soil profile. However, in all parameters, the 60 cm soil depth showed that the concentrations levels are similar to before the aplication of treatments

Recent Developments in Chitosan-Based Nanocomposites

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