Conversion of Lactose to Calcium Lactobionate by Some Bacterial Species

Abstract

Bacterial conversion of lactose to calcium lactobionate was carried out by twelve strains of bacteria. The strain Bacillus spp. E showed high lactose oxidizing activities, when cultivated at 30˚C for 7 days in a medium ( pH 6) containing (g/100ml): lactose ,5; KH 2 PO 4 ,0.06 ; MgSO 4 .7H 2 O, 0.025; corn steep liquor ,0.75 ml ; 1 drop of soybean oil ; 1.5ml of 20% urea solution and CaCO 3 ,2.5 added during inoculation. The oxidizing activity was the highest where a relatively high lactose conversion (82%) was obtained at a lactose concentration of 50g/l . The activity remained almost stable between pH 5 and 6 and high conversion efficiency ( about 90%) was achieved at pH 0.6.