Carotenoids from Phaffia rhodozyma: Antioxidant activity and stability of extracts

The main goal of this work was to establish the stability and antioxidant activity of the extracts obtained through different techniques for recovering carotenoids from Phaffia rhodozyma NRRL-Y 17268. The best conditions for extracting carotenoids through cell rupture with dimethylsulfoxide (DMSO) were found to be a particle size of 0.125 mm submitted to freezing temperature (-18°C) for 48 h (272 μg/g). For DMSO extracts, freezing negatively affected the antioxidant activity by 2,2 '-azinobis (3-ethyl benzothiazoline-6-sulfonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The carotenogenic extracts obtained by enzymatic disruption proved to be more promising in relation to its antioxidant activity.Key words: Microbial carotenoids, antioxidant properties, cell wall disruption

Production of a rhamnolipid-type biosurfactant by Pseudomonas aeruginosa LBM10 grown on glycerol

The work herewith investigated the effect of the culture medium composition on rhamnolipid production by Pseudomonas aeruginosa LBM10, previously isolated from an estuarine environment in Southern Brazil. Experimental design and surface response methodology were used in order to improve biosurfactant production using glycerol, a renewable carbon source. The assays were carried out in a rotary shaker at 30°C and 180 rpm for 120 h and the parameters studied were glycerol concentration, C/N (carbon/nitrogen) and C/P (carbon/phosphorus) ratios. Low glycerol concentration and a phosphorus-limiting condition were favorable for rhamnolipid production. Contour plots constructed by predictive polynomial equations led to a glycerol concentration of 13.2 g/l, a C/N ratio of 12.8 and a C/P ratio of 40 in order to maximize rhamnolipid concentration (4.15 g/l) associated with a high emulsification index (61%).Keywords: Biosurfactant, surface-active compounds, experimental design, phosphorus limitatio

Different cell disruption methods for astaxanthin recovery by Phaffia rhodozyma

Astaxanthin (3,3'-dihydroxy-b,b'-carotene-4,4'-dione) is carotenoid of high market value whose demand has increased in such fields as aquaculture, pharmaceutical supplements and natural coloring. Cell disruption is the first step for isolating intracellular materials and it depends on the cell wall permeability. In order to maximize the  recovery of astaxanthin from Phaffia rhodozyma NRRL-Y17268, drying and freeze pretreatments were tested by different cell disruption methods: abrasion with celite, glass pearls in vortex agitator, ultrasonic waves, sodium  carbonate (Na2CO3) and dimethyl sulfoxide (DMSO). The method with Na2CO3 was not effective; meanwhile, the agitator with glass pearls, the abrasion with celite and the ultrasonic waves were found as promising for future  studies. As a result, the DMSO in freeze-dried biomass with 4 process cycles and biomass/DMSO relation of 0.025 g/ml was found to be the most efficient for analytical determination, increasing about up to 25 times the astaxanthin recovery.Key words: Carotenoids, yeast, chemical disruption, dimethyl sulfoxide

Ultraviolet Completion of Flavour Models

Effective Flavour Models do not address questions related to the nature of the fundamental renormalisable theory at high energies. We study the ultraviolet completion of Flavour Models, which in general has the advantage of improving the predictivity of the effective models. In order to illustrate the important features we provide minimal completions for two known A4 models. We discuss the phenomenological implications of the explicit completions, such as lepton flavour violating contributions that arise through the exchange of messenger fields.Comment: 18 pages, 8 figure

COVID-19, Food Insecurity and Malnutrition: A Multiple Burden for Brazil.

No abstract available

Evapotranspiração e coeficientes de cultivo da beterraba orgânica sob cobertura morta de leguminosa e gramínea.

As práticas agrícolas que maximizam a produtividade e o uso da água são de vital importância para a agricultura. Assim, foram testados três tipos de manejo do solo com objetivo de determinar a evapotranspiração (ETc) e os coeficientes de cultivo (kc) da beterraba. Os tipos de manejo foram a utilização de coberturas mortas vegetais, denominadas capim cameroon (Pennisetum purpureum), gliricídia (Gliricidia sepium) e solo sem cobertura morta em área experimental do SIPA (Sistema Integrado de Produção Orgânica) localizado em Seropédica, Brasil. A lâmina de irrigação foi estimada com base no balanço de água no solo, cujo monitoramento foi realizado com a técnica da TDR. As ETc acumuladas para a cultura da beterraba foram 59,41; 55,31 e 119,62 mm, respectivamente, para capim cameroon, gliricídia e solo sem cobertura morta. A evapotranspiração de referência (ETo) foi obtida por meio do modelo de Penamn-Monteith. Os valores médios de kc obtidos para as fases inicial, média e final de desenvolvimento foram de 0,39; 0,42 e 1,02; 0,79; 0,76 e 1,18; e 0,56; 0,61 e 0,84, respectivamente, para capim cameroon, gliricídia e solo sem cobertura morta. O uso da cobertura do solo com gramínea ou leguminosa minimizou de forma expressiva a demanda hídrica da cultura da beterraba (Beta vulgaris)