Microbial communities of karst caves as a potential source of low-temperature amylase producers

Автор: Khizhnyak Sergey Vitalevich, Pampuha Vladimir Tarasovich

Журнал: Вестник Омского государственного аграрного университета @vestnik-omgau

Рубрика: Биологические науки

Статья в выпуске: 1 (21), 2016 года.

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Six strains of cold-adapted amylolytic fungi of the genus Geomyces isolated from low-temperature karst cave were examined for their growth rates at different temperatures, and for two of them the effect of temperature on amylolytic activity of cultural liquid (CL) was studied. It was found that effect of temperature on growth rates is well described by Ratkowsky et al. (1983) equation with the coefficients of determination R2 0.987-0.999, and effect of temperature on amylolytic activity at 31-50°C is well described by the logistic function (R2 = 0.994 and 0.997). All the strains are unable to grow at temperature 30°C and higher. Five strains are psychrotolerant with the optimal growth temperatures in the range from 21.50 to 25.25°C and one strain is psychrophilic with the optimal growth temperature 18.50°C. Comparison of temperature effect on the amylolytic activity of CL showed that the temperature value of the sigmoid's midpoint for the psychrophilic strain is 7°C lower then that of the psychrotolerant strain, what is almost equal to the difference in the optimal growth temperatures of these strains (6°C). The slope of log-lin plot of amylolytic activity of CL of the psychrophilic strain in the exponential area of the temperature curve is 2 times higher than that of the psychrotolerant strain. These results shows that decrease of optimal growth temperature in the process of adaptation to cave environment leads to the corresponding decrease of the temperature optimum of amylolytic enzymes and demonstrates perspectiveness of search for low-temperature amylase producers in cave communities.

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Low-temperature amylase, producers, karst caves, filamentous fungi, psychrophiles

Короткий адрес: https://sciup.org/142199108

IDR: 142199108

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