Abstract
Pseudomonas fluorescens was isolated from raw milk. It was found to be a high incidence, active lipase producing psychrotrophic organism. Its lipolytic activity on Spirit Blue Agar media varied with the incubation time and temperature. It appeared after 12 h at 6 ℃, while at 30℃ it was stronger after 6 h. Its extracellular lipase showed maximum activity at 2 % tributyrin. Lipase enzyme exhibited optimum temperature of 40℃ and it still had some of its activity at 5℃. It had some stability at 65℃ for 5 min, 105℃ for 5 sec and 115℃ for 5 sec. The enzyme could escape some industrial heat treatments that commonly used in dairy practices. The optimum pH was 8. It showed 63. 63 % of its maximum activity at pH 6.6 (pH of milk). It had a slight stability over a pH range 8-9.
