Effect of scandium on amylase production by Bacillus subtilis

Scandium, lutetium, and gadolinium were selected from rare earth elements, and their effects on amylase activity secreted into the culture supernatant were examined when they were added to the NG medium. NG medium was prepared using bacto tryptone, meat extract, glucose, and NaCl. Using each rare earth element chloride, aqueous solutions were prepared so that the rare earth element concentrations were 2, 5, 10, and 20 µg/mL. After adding each rare earth aqueous solution to NG medium and inoculating Bacillus subtilis, cultivation was carried out. After 24, 48, 72, and 96 h of cultivation the cells were removed by centrifugation to obtain a culture supernatant. Amylase activity increased 3.3 times after 96 h of cultivation for scandium with 2 µg/mL addition, 2.1 times after 96 h of culture for lutetium with 5 µg/mL addition, and 1.1 times after 96 h of culture for gadolinium with 5 µg/mL. A significant improvement in amylase activity was observed when scandium was added.