Abstract The present study is concerned with the selection
of a new economical medium for growth and production of
a calcium-dependent protease by Bacillus cereus BG1
strain.Various fish powders were prepared from sardinelle
(Sardinella aurita) and then tested for the growth and the
production of protease by Bacillus cereus BG1 strain:
whole sardinelle powder (WSP), meat sardinelle powder
(MSP) and combined heads and viscera sardinelle powder
(CHVSP). Protease synthesis was significantly low when
the strain was grown in media containing only fish
powders. However, the addition of Ca2+ to the fish media
enhanced the production of protease. Maximum activity
was obtained on CHVSP followed by WSP. Other metal ions,
such as Mg2+, Mn2+ and Ba2+, were also found to enhance
protease production. However, in media containing maltose
as carbon source and ammonium sulfate as nitrogen source,
protease activity was detected only when media were
supplemented with CaCl2.These results clearly indicated that
the utilization of fish powders, in particular that produced
from sardinelle by-products, may result in a cost-effective
process suitable for large-scale production of proteases.