3.1. Effect of different carbon and nitrogen sources
Based on the literature reports of organic solvent-stable protease production, the shake-flask cultivation was performed by using the medium and the culture conditions described above and then the protease activity was observed as 366.08 U/mL. Among the various nitrogen sources tested, casein exhibited a prominent effect on the production ability and maximum protease yield (461.52 U/mL), followed by soybean meal (449.71 U/mL). Very low level of protease production was observed in the presence of inorganic nitrogen sources (data not shown). Among carbon sources, glycerol (465.06 U/mL) favored maximum protease production, followed by glucose (date not shown)