Résumé
Gram-positive rod-shaped thermophilic bacteria were isolated using samples collected from terrestrial natural thermal spring located at Unkeshwar (Longitude 78.22 degree East to 78.34 degree East, Latitude 19 degree 34' North to 19 degree 40' North), District Nanded, Maharashtra State, India. The isolates were then cultivated using selective media and identified using culture-dependent techniques. One prominent isolate (UN1) exhibited high temperature stability and remarkable amylase production and was identified as Bacillus licheniformis. Amylase production was carried out in starch media and the enzyme was partially purified and characterized for optimization of pH and temperature. Amylolytic activity of the enzyme was determined. Nanoactivator-mediated modifications were carried out to enhance amylolytic activity of the partially purified amylase. Three-fold increase in catalytic efficiency of amylase was obtained after modification.
Sujets)
Amylases/composition chimique , /métabolisme , Bacillus , Nanostructures , ThermoplasmalesRésumé
A bacterium producing an alkaline protease was isolated from the Lonar soda lake, Buldhana district (19°58' N; 76°31' E), Maharashtra, India. The most appropriate medium for the growth and protease production was composed of (g/L): casein 10; yeast extract 4; KH2PO4 0.5, K2HPO4 0.5 and CaCl2 0.5. The enzyme showed maximum activity with and without 5 mM Ca2+ at 70 and 60 oC, respectively. The enzyme retained 40 and 82% of its initial activity after heating for 60 min at 60 oC, in absence and presence of 5 mM CaCl2 respectively. The enzyme remained active and stable at pH 8-12, with an optimum at pH 10. The enzyme showed stability towards non-ionic and anionic surfactants, and oxidizing agents. It also showed excellent stability and compatibility with commonly used laundry detergents. Wash performance analysis revealed that enzyme could effectively remove blood stains. It also showed decomposition of gelatinous coating on X- ray film.