Characterization of a Protease from a Psychrotroph, Pseudomonas fluorescens 114

A psychrotrophic bacterium isolated from river sediment was identified as Pseudomonas fluorescens 114. It grew at 0 degrees C and optimally at 20 degrees C. The bacterium produced a protease with a molecular weight of 47,000, which was stable in the pH range of 5 to 9 and worked optimally between pH 6.5 and 10. Activity was optimal at 35 degrees C and was lost immediately at 50 degrees C and after 5 min at 45 degrees C. At 0, 10, and 20 degrees C, 24, 38, and 57% of optimal activity were observed, respectively.