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Characterisation of a thermotolerant yeast, Kluyveromyces marxianus CBS712
7-13Views:140Fermentation at high temperature with application of thermotolerant microorganisms is a technological advantage in bioethanol production. Among the yeasts, K. marxianus has outstanding thermotolarance. The industrial application of the IMB3 strain occurs usually at 45C. The final aim of our project is the genetic modification of the K. marxianus CBS712 strain in order to achieve ethanol production at higher temperature than the currently applied. This requires the characterization of the CBS712 strain, with special attention to the determination of the temperature limit of its growth and the amount of the ethanol produced. The temperature limit of growth was 48C in YPD medium. Elevation of the temperature above 45C led to an exponential drop of the cell viability. Ethanol production was tested in shaking flasks, in MYFM medium, under oxigene limited conditions, applying variable concentrations of glucose (12–20%) and different temperatures (45–47 ºC). Preliminary results have revealed that the elevation of glucose concentration increased the amount of ethanol produced. The amount of ethanol (appr. 5%)+ produced at the highest glucose concentration was not different at the tested temperatures (45, 46 and 47 ºC). The observation indicates the potential in raising the thermotolerance of the strain.
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The age and the growth of the european weather loach (Misgurnus fossilis)
37-44Views:196The possibilities of examination the growth of fish species are verry difficult, and much of methods are oblique. With the weather loach is the work especially complicated through the small scales. Till now the growth of weather loach is in Hungary unexamined.
We applied self developed catch method in three explored channel. The length and weight measured on the fishes alive, as well the sexing. We analysed the datas with Bertalanffy-method.
The growth of the fishes is different, but the growth of the body length was nearly the same in the three channels. The one year old fishes can growth to a maximum of 130-140 millimeters, the two years old fishes can growth to maximum of 180-190 millimeters. Longer fishes by 180-190 millimeters are 3 or more years old. The data of sex-ratio is deviant than the literature wroted. The fish from Fényes are growing faster, than the others. This species can be 190-200 millimeters long after 2 years from birth. It is a very fast growing.