Search

Determination of optimum temperature in the (PFasa) cellulase production, by a strain of Aspergillus niger in solid fermentationis presented in this paper, using data from a previously proposed kinetic model. Dependence of the 16 kinetic parameters with temperature (in the range of 20 °C to 40 °C), was established. For µmax and xmax parameters, the adjustment was achieved using the Rosso and Ratkowsky models respectively. Cubic interpolation models was needed to adjust the rest of kinetic parameters. The dependence of the kinetic model parameters with temperature allowed the estimation of temperature and optimum fermentation time to maximize the productivity in the production of true protein and the activity of the three studied enzymes. As result, the optimum temperature rangeisbetween 30°C and 32°C. For the production of true protein and CMcasa, the optimum fermentation time is located within the19 and 22 hours respectively, but for the production of PFasa, is 33 hours. The protease activity presented several local maxima in terms of optimal temperatures ranging from 25 to 40 °C. Although the maximum activity levels are 64 UI/gdm, which, according to literature, is an intermediate value, the level of productivity of PFasa is the highest found (3.84 times superior to average activity), when compared with another 20 reports consulted since 2004. [ABSTRACT FROM AUTHOR]

In this work a kinetic model proposal is presented for describing cellulase production in a solid-state fermentation process of an Aspergillus niger strain. The validation of the model was carried out at five temperatures: 20, 25, 30, 35 and 40°C. In the validation the characteristic parameters of the model were identified using a dynamic data generated at constant temperature. The response variables described by the model are: concentration of biomass of fungus measured as true protein, total reducing sugars, crude fiber, FPase activity, CMCase activity and the activity of proteases in the medium. For parameters identification the process model was programmed in MATLAB. The results indicate that the model is perfectly capable describing the cellulase production kinetics under these conditions. The temperatures where cellulase production was higher were 30°C and 35°C. The experimental levels of FPase and CMCase are significant because maxim values of FPase of 60 UI gDW-1 and of CMCase of 50 UI gDW-1 are reached in a fermentation time ranging from 24 to 30 hours. The identified parameters are strongly associated to temperature. [ABSTRACT FROM AUTHOR]

In this work, a kinetic study is presented analyzing the influence of the initial pH on (PFasa) cellulase production by an Aspergillus niger strain, cultured in solid-state fermentation. The results showed that the optimum value of initial pH for PFasa production was 4.5. The PFasa activity reached 25.11 UI/gMS in 18 hours and a productivity of 1.40 UI h-1gMS-1 under these initial pH conditions. [ABSTRACT FROM AUTHOR]

We describe a new species of the bufonid toad genus Rhinella from transition montane forest of the buffer zones of the Yanachaga-Chemillén National Park and the Pui Pui Protected Forest (eastern slopes of Andes, Selva Central, Peru). The new species belongs to the Rhinella margaritifera species group (confirmed by mtDNA data) and differs from all its members by the absence of tympanic membrane and tympanic annulus. It is characterized by medium size (SVL 57.5-65.5 mm, n = 5), moderately developed cranial crests, absence of neural crest of vertebrae, absence of bone protrusion at angle of jaw, presence of lateral rows of enlarged tubercles, and absence of subgular vocal sac and vocal slits in males. In addition, based on the molecular phylogenetic analyses of selected Rhinella species we propose the monophylum containing R. chavin, R. festae, R. macrorhina, R. manu, R. nesiotes, R. rostrata, and R. yanachaga as a new species group under the name Rhinella festae species group.

Objective: To compare olanzapine versus haloperidol effectiveness, in terms of relapse rates in Venezuelan patients with schizophrenia., Methods: A randomized, open label, follow-up study of 9-months after clinical stabilization or hospital discharged was conducted. The Medical Outcomes Study Form Health Survey (SF-36) and the Quality of Life Index from Mezzic & Cohen were used to evaluate the health state and quality of life. Safety parameters were collected., Results: Thirty-one patients in olanzapine and 40 in haloperidol were enrolled and discontinuation rates were 65% and 68% respectively. Only one patient in haloperidol relapsed. Health status improved more with olanzapine showing statistically significant improvement in five of the eight items of the SF-36. Olanzapine was slightly superior improving quality of life. More adverse events were registered with haloperidol (p = 0.036). More extrapyramidal symptoms, akathisia and insomnia were reported with haloperidol and more weight gain with olanzapine but the differences were not significant., Conclusions: Both medications were similar preventing relapses. Health status and functionality improved more with olanzapine versus haloperidol. Safety results are consistent with the known profile of the drug. Study limitations on design and conduction of this study restrict its generalization.