Proteases are essential constituents of all forms of life on earth. Microbial proteases are
among the most important, extensively studied groups since the development of
enzymology. Alkaline proteases are so far exploited as industrial catalysts in various
industrial sectors. Neutralophilic and alkaliphilic microbial alkaline proteases possess a
considerable industrial potential due to their biochemical diversity and stability at
extreme pH environments, respectively (Moon et al. 1994). However, the demanding
industrial conditions for technological applications and cost of alkaline proteases production
resulted in continuous exercise for search of new microbial resources. Extreme environments
are important sources for isolation of microorganisms for novel industrial
enzymes production (Kumar & Takagi, 1999). Enzyme cost is also the most critical factor
limiting wide use of alkaline proteases for different applications. A large part of this cost
is accounted for the production cost of the enzyme. Therefore, reduction in the production
cost of enzymes could greatly reduce the cost of the enzyme. In submerged fermentation
up to 40% of the total production cost of enzymes is due to the production of the growth
substrate (Enshasy et al. 2008; Kirk et al. 2002). In this regard, SMF method is used to
optimize the parameters of enzyme production and SSF which uses cheap agricultural residues
which have enormous potential in reducing enzyme production cost. So, studies on
alkaline proteases that are produced in SMF and SSF by alkaliphilic microorganisms are
scarce in literature as a result, it is of great importance to pursue such studies.