This work aimed at evaluating the biodegradability of different bacterial surfactants in liquid medium and in soil microcosms. The biodegradability of biosurfactants by pure and mixed bacterial cultures was evaluated through CO(2) evolution. Three bacterial strains, Acinetobacter baumanni LBBMA ES11, Acinetobacter haemolyticus LBBMA 53 and Pseudomonas sp. LBBMA 101B, used the biosurfactants produced by Bacillus sp. LBBMA 111A (mixed lipopeptide), Bacillus subtilis LBBMA 155 (lipopeptide), Flavobacterium sp. LBBMA 168 (mixture of flavolipids), Dietzia Maris LBBMA 191(glycolipid) and Arthrobacter oxydans LBBMA 201(lipopeptide) as carbon sources in minimal medium. The synthetic surfactant sodium dodecyl sulfate (SDS) was also mineralized by these microorganisms, but at a lower rate. CO(2) emitted by a mixed bacterial culture in soil microcosms with biosurfactants was higher than in the microcosm containing SDS. Biosurfactant mineralization in soil was confirmed by the increase in surface tension of the soil aqueous extracts after incubation with the mixed bacterial culture. It can be concluded that, in terms of biodegradability and environmental security, these compounds are more suitable for applications in remediation technologies in comparison to synthetic surfactants. However, more information is needed on structure of biosurfactants, their interaction with soil and contaminants and scale up and cost for biosurfactant production.
R E S U M OA diagnose foliar é o método de maior relevância na definição e na interpretação do estado nutricional das plantas. A interpretação correta sobre o estado nutricional da cultura só é possível quando se regionalizam os valores de referência. Objetivou-se, com este trabalho, determinar índices diagnósticos para interpretação de resultados de análise foliar de milho mediante o uso dos métodos de interpretação: Nível crítico (NC), Faixa de suficiência (FS) e Índices Balanceados de Kenworthy (IBK). Amostraram-se solos, folhas e produtividade em 120 lavouras de milho, nas safras agrícolas 2010/2011 e 2011/2012, na região do Alto Paranaíba, MG. Para gerar os índices diagnósticos pelos métodos FS e IBK a população foi dividida em duas subpopulações, com base na produtividade: acima ou abaixo de 11.795 kg ha -1 . Os teores de nutrientes propostos como adequados pelos métodos citados foram semelhantes. A amplitude das faixas ótimas foi menor que a encontrada na literatura para milho. Os índices diagnósticos regionalizados pelos métodos NC, FS e IBK aumentam a confiabilidade ao diagnosticar talhões com as mesmas características das normas estabelecidas em relação a valores de referência universal. Diagnostic index for interpretation of foliar analysis of corn A B S T R A C TAt present, the leaf analysis is the method of greatest relevance in the definition and interpretation of nutritional status of plants. The correct interpretation of the nutritional status of the crop is only possible when it regionalizes reference values (standards). This study aimed to determine reference values for the interpretation of the results of leaf analysis of maize through the use of methods of interpretation: critical levels (CL), sufficiency range (SR) and balanced indexes of Kenworthy (BIK). Sampling of soil, leaves and productivity was conducted in 120 commercial crops of corn, in the crop year of 2010/2011 and 2011/2012, in the region of Alto Paranaíba, MG. To generate the diagnostic indexes by the methods SR and BIK, the population was divided into two sub-populations: with the productivity above and below 11,795 kg ha -1 . Levels and normal ranges proposed by the cited methods were very similar. The amplitude of optimum ranges were lower when compared to that one found in the literature. The diagnostic indexes regionalized by the methods CL, SR and BIK increased the reliability when diagnosing plots with the same characteristics of the standards approved in relation to universal reference values. Palavras-chave:Zea mays L. nível crítico equilíbrio nutricional
Some compounds present in coffee beans can affect consumer health. The present study determines the content of heavy metal in coffee cultivated in the Cerrado Mineiro region (Alto Paranaíba-MG, Brazil), to compare the values found with the legal standards and check how these metals are extracted from the respective infusions. Fifty samples of coffee beans we re analyzed, taken from the Alto Paranaíba region, MG, Brazil. Determination and quantification were done by recording the values from the atomic absorption spectrophotometer for the metals mentioned: cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn). The Cr concentrations presented earlier the limit allowed by law in 66% of the coffee samples. And 74% of the samples contained Pb in higher than permissible concentrations. For all the infusions, the metals evalua ted were found in lower concentrations and were less significant with respect to the maximum permissible daily intake, except for Pb were quantified very high levels. Only seven of the 50 coffee samples revealed results with levels that were quantified to be within the legally stipulated standards. The Pb and Cr metals were found to have the highest percentage of leaching in the coffee infusions.
Farmers must carefully choose the cultivar to be grown for a successful carrot crop. The yield potential of the cultivar may influence nutrient demand and should be known to plan for fertilization application. The aim of this study was to evaluate the cultivar effect on carrot yield and on the nutrient content and quantities allocated to leaves and roots. Three experiments were set up in two crop seasons in Rio Paranaíba, MG, Brazil. In the first season, typical summer, 10 summer cultivars were sown. In the second season, summer-winter (transition), two experiments were set up, one with summer cultivars and the other with winter cultivars. The treatments consisted of the carrot cultivars distributed in randomized blocks with four replications. Fresh and dry matter of the roots and leaves was quantified. Yield was calculated based on fresh matter of the roots. The nutrient content in leaves and roots was determined at the time of harvest. These contents and the dry matter production of roots and leaves were used to calculate nutrient uptake and export. The greatest average for total and commercial yield occurred in the crop under summer conditions. Extraction of N and K for most of the cultivars in the three experiments went beyond the amounts applied through fertilizers. Thus, there was contribution of nutrients from the soil to obtain the yields observed. However, the amount of P taken up was considerably less than that applied. This implies that soil P fertility will increase after cropping. The crop season and the cultivars influenced yield, nutrient content in the leaves and roots, and extraction and export of nutrients by the carrot crop.
ABSTRACT. This study evaluated the physical and chemical characteristics of the papaya 'Solo' cv. 'Golden' (Carica papaya L.) coated with propolis extract drawn from various botanical sources, during storage at room temperature. Papayas underwent three types of dip coating propolis extract, in 2.5% (w v -1 ) concentration ('aqueous extract' and 'hydroalcoholic extract of propolis wild type', 'hydroalcoholic extract of the propolis green rosemary'), at ambient temperature and two controls (without coating, one at 'ambient temperature' and the other 'refrigerated'). The variables weight loss, firmness, soluble solids (SS), titratable acidity (TA), maturation index ratio (SS/TA) and hydrogen potential (pH) were evaluated, at three day intervals for twelve storage days. Sensory analyses of the papayas were performed on days three and six of storage, by acceptance testing. Coatings with hydroalcoholic extract of propolis wild type and green rosemary controlled weight loss and firmness in papayas. The coatings showed no effect on the variable SS. Fruit coated with hydroalcoholic extract of rosemary green propolis showed satisfactory results evaluating AT, SS/TA and pH, as well as sensory analysis. Thus, the coating formulated with propolis extract can be used as an alternative to extend the shelf life of papaya fruits.
Surfactants and inorganic ligands are pointed as efficient to simultaneous removal of heavy metals and hydrophobic organic pollutants from soil. However, the biosurfactants are potentially less toxic to soil organisms than other chemical agents. Thus, in this study the efficiency of combinations of iodide (I(-)) ligand and surfactants produced by different bacterial species in the simultaneous removal of cadmium (Cd(2+)) and phenanthrene in a Haplustox soil sample was investigated. Four microbial surfactants and the synthetic surfactant Triton X-100 were tested with different concentrations of ligand. Soil samples contaminated with Cd(2+) and phenanthrene underwent consecutive washings with a surfactant/ligand solution. The removal of Cd(2+) increased with increased ligand concentration, particularly in solutions containing biosurfactants produced by the bacterial strains Bacillus subtilis LBBMA155 (lipopeptide) and Flavobacterium sp. LBBMA168 (mixture of flavolipids) and Triton X-100. Maximum Cd(2+) removal efficiency was 99.2% for biosurfactant produced by Arthrobacter oxydans LBBMA 201 (lipopeptide) and 99.2% for biosurfactant produced by Bacillus sp. LBBMA111A (mixed lipopeptide) in the presence of 0.336 mol iodide l(-1), while the maximum efficiency of Triton X-100 removal was 65.0%. The biosurfactant solutions removed from 80 to 88.0% of phenanthrene in soil, and the removal was not influenced by the presence of the ligand. Triton X-100 removed from 73 to 88% of the phenanthrene and, differently from the biosurfactants, iodide influenced the removal efficiency. The results indicate that the use of a single washing agent, called surfactant-ligand, affords simultaneous removal of organic contaminants and heavy metals.
-In the present work were evaluated the effects of propolis coatings of various botanical sources on quality traits of bananas cv. Prata (Musa sapientum L.) stored at room temperature. ´Prata´ bananas were selected and submitted to five postharvest treatments: four coatings applied by immersion in propolis extracts at a concentration of 2.5% (w/v) and a control (without coating). Propolis extracts were applied as 1) a wild type aqueous propolis extract, 2) a wild type hydroalcoholic propolis extract, 3) a rosemary green type hydroalcoholic propolis extract and 4) a red type hydroalcoholic propolis extract. The bananas were evaluated at three-day intervals along 12 days for fresh weight losses, flesh firmness, soluble solids (SS), titratable acidity (TA), the ratio SS/TA and pH. Sensory analyses were performed after three and six days of storage by 55 not trained panelists designed for acceptability. At the end of the twelve-day storage period, bananas coated either with the rosemary green hydroalcoholic extract or with the aqueous extract presented lower fresh weight losses in comparison to the bananas of the control treatment. No differences were determined in relation to flesh firmness and along the storage period TA values decreased and pH values increased in bananas of all treatments. SS contents increased towards the end of the storage period that, consequently, contributed to increases in the SS/TA ratio. The most significant increase in SS/TA ratio was determined in bananas coated with the red type hydroalcoholic extract. Taste panelists did not detect significant differences amongst coated and not coated cv. Prata bananas up to six days of storage. Index terms: Musa sp., hydroalcoholic extract, taste panel, fruit acceptability, storage. EXTRATO DE PRÓPOLIS NA CONSERVAÇÃO PÓS-COLHEITA DE BANANA 'PRATA'RESUMO -Este trabalho foi realizado com o objetivo de avaliar os efeitos do revestimento com extrato de própolis de diferentes fontes botânicas sobre as características físico-químicas de banana 'Prata' (Musa sapientum L.), armazenada à temperatura ambiente. Bananas 'Prata' foram selecionadas e submetidas à cinco tratamentos pós-colheita, sendo quatro formas de revestimento por imersão em extrato de própolis de diferentes fontes botânicas com concentração de 2,5% (m/v) ("extrato aquoso de própolis do tipo silvestre", "extrato hidroalcoólico de própolis do tipo silvestre", "extrato hidroalcoólico de própolis do tipo verde alecrim e "extrato hidroalcoólico de própolis do tipo vermelho ") e um controle (sem revestimento). As variáveis avaliadas foram perda de massa, firmeza da polpa, sólidos solúveis (SS), acidez titulável (AT), relação entre sólidos solúveis e acidez titulável (SS/AT) e potencial hidrogeniônico (pH), realizadas em intervalos de 3 dias por 12 dias de armazenamento. Realizou-se a análise sensorial das bananas aos 3 e 6 dias de armazenamento, avaliadas por 55 provadores não treinados através do teste de aceitação. Ao final de 12 dias de armazenamento, os revestimentos de extrato de própo...
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