Abstract
An invesigation on optimal temperature for the growth and protease production of a mesophilic bacterium, Aeromonas hydrophila was carried out. The studied 12 strains of fish origin were collected and stored at -80deg;C. Optimal growth temperature was determined by a temperature gradient incubator using TYE medium, a suitable medium for protease production. The protease production was estimated by the Bio-Rad DC protein assay with broth culture supernatant at around stationary phase. Casein (Hammarsten quality) was used as a protein substrate. There was no considerable amount of protease within log phase culture. Although the optimum temperatures for growth and protease production were variable with the strain, optimal temperatures for protease production were always lower than those for the growth. Peak growth was favoured at 34.5±1.0deg;C, while the protease production at 27.6±4.9deg;C. The differences among the peaks of protease production and growth were 1 to 15deg;C.
