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° 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.Correspondence to: N. Orange