Temperature regulation of lipase secretion by Pseudomonas fluorescens strain MFO

The psychrotrophic bacterium Pseudomonas fluorescens is a milk contaminant known to secrete a lipase that is a nuisance for the dairy industry but may have a biotechnological interest. Strain MFO secretes this enzyme upon induction under various conditions. Regardless of the inducer and growth temperature, a single enzyme is produced. However, optimal production occurs when the culture is grown at 17.5 degrees C. Other exported proteins (an extracellular protease and two periplasmic phosphatases) have previously been shown to display exactly the same optimal temperature of production. In contrast, constitutive cell-bound esterase and cytochrome oxidase are produced at a roughly constant rate regardless of the growth temperature. The relevance of these results are discussed in terms of multifunctional regulation and interest for the dairy industry.