Isolation and characterzation of ?-amylase from lactic acid bacterium

In this study, whey samples from Diyarbakır cheese market place were collected and lactic acid bacteria were isolated. These bacteria which were isolated were described with the aid of morphological, physiological, and biochemical tests and named as PS-2A, PS-3B, PS-3C and PS-4B. And then, by investigating extracellular ??amylase production capabilities of these bacteria, PS-2A bacterium which showed the best activity was selected. It was found that bacterium PS-2A was round-like, Gram positive,catalase negative, active. For produce the PS-2A; the optimum incubation time as 16th hours, optimum pH as 7.0 and optimum incubation temperature was determined as 35°C.After that extracellular ??amylase enzyme production capabilities of the PS-2A were studied and the optimum conditions of the enzyme were determined. It was found that PS-2A conducted its optimum ??amylase activity at the 20th hour (1847 U/mg) in LB medium performed, and optimum pH and temperature values of ??amylase activity were 7.0 and 35°C, respectively.By adding diverse carbon (glucose, galactose, fructose, soluble starch, maltose and sucrose) and nitrogen (peptone, tryptone, urea, ammonium sulphate, ammonium chlorid ve casein) sources to PS-2A?s medium the effects of these on ??amylase production were investigated.In carbon sources; The %1 soluble starch was increased the ??amylase production 2 fold (4743 U/mg), and it was determined that the enzyme production was decreased by adding glucose (1392 U/mg), fructose (468 U/mg) ve maltose (1158 U/mg).In nitrogen sources; it was determined that with %1 peptone (2550 U/mg), tryptone (3527 U/mg), ammonium sulphate (3463 U/mg) and ammonium chlorid (4166 U/mg) the ??amylase production was increased and by adding urea (1241U/mg ) and casein (1960 U/mg) the enzyme production was decreased.