Cold-active Protease from antarctic bacterium marinobacter sp. Strain R2:fermentation condition and enzyme properties

A strain R2,which produces protease,was isolated from the Antarctic Ocean sediment samples.Results of morphology and 16S rDNA sequence analysis showed that R2 belonged to Marinobacter.The Marinobacter sp.strain R2 was facultative psychrophile because it grew best at 10～15℃.The strain could produce protease with many kinds of single carbonaceous substance,and produced maximum protease activity at 20℃.The primary purification was performed by ammonium sulfate fractionation and column chromatography with DEAE cellulose-52.The optimum condition for the protease activity was 20℃ and pH 9～10,which suggested the enzyme was a typical alkaline cold-active protease.The protease activity was stimulated by Ca~(2+)、Mn~(2+)、Cu~(2+),and was inhibited by Cd~(2+)、Co~(2+).This enzyme appeared to be a serine protease,on the basis of its sensitivity to PMSF and AEBSF.From the result that EDTA showed obvious inhibiting effect on the enzyme,it can be suggested that metal ions played an important role in the conservation of enzyme conformation for the catalytic activity.