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Characteristics of bacterial strain, superoxide dismutase producer, isolated from Bulgarian thermal spring
Ivanka Bojadzhieva and Elka Emanuilova
Abstract
Twenty one bacterial strains with superoxide dismutase activity were isolated from samples (flowing spring water, water with soil particles, alga bacterial mad and mud) collected near different thermal Bulgarian springs. The strains were Gram positive, rod shaped, spore forming and moderate thermophiles. Isolate M 20 showed the highest specific total superoxide dismutase activity of 530 U/mg in shaken flasks cultivation at 55 °C for 4 hours. An activity of 1300 U/mgwas achieved after selection and optimization of cultivation procedures in fermentor. The optimal enzyme activity of cell free extract was at 55 °C and pH 8.0, and the half-life was 30 min at 90 °C. The strain was catalase positive, it produced peroxidase and proteinase. As a result of morphological, cultural, physiological and biochemical characteristics the isolate M 20 was determined as a moderate thermophile belonging to the genus Bacillus.
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