Table 2.

Effect of nitrogen sources on protease production by B. circulans MTCC 7942.

Nitrogen supplementation (1%)#	Protease activity (U/mL ± SD)	Specific activity (U/mg ± SD)
Feather meal	69.5 ± 6.9	222.6 ± 21
Bovine serum albumin	216.5 ± 18.4	635.9 ± 55
Beef extract	300.6 ± 12.0	905.7 ± 41
Casein	320.7 ± 6.0	884.2 ± 114
Casamino acids	329.1 ± 13.3	966 ± 31
Yeast extract	330.1 ± 23.8	875.8 ± 163
Gelatin	339.2 ± 10.0	1063.0 ± 39
Peptone	357.0 ± 10.5	1007.0 ± 75
Soybean meal	397.0 ± 7.6	1164.0 ± 33

^#Basal medium containing (g/L): starch, 20; KH₂PO₄, 1; MgSO₄·7H₂O, 0.05; CaCl₂, 1; Na₂CO₃, 8 and cultural parameters (pH 10.0) at 37°C and 100 rpm.