Nutritional Factors Influencing Growth and Lipase Production by Geotrichum Candidum

Abstract

The conditions necessary for optimum microbial lipase activity vary with the source of the enzyme, the substrate, and the treatment accorded the lipase preparation. Similarly, it appears that the production of bacterial and fungal lipases is related directly to the nutritional and physical environment of the cultures under observation. Thus, it has been suggested (1) that certain bacterial tipases are adaptive in nature and that production is stimulated by the presence of specific substrates, or that the elaboration of the enzyme d,epends upon preferential utilization of certain substrates by the organisms. Peters and Nelson (3) observed with Candida lipolytica that low lipase activity was associated with conditions favorable for rapid growth, whereas high lipase activity was associated with less favorable conditions. In this connection, Tammisto (9) suggested that the failure of certain lipolytic species to hydrolize fat when they were grown on glycerol-fat agar was due to the inactivation of the lipase by acids developed in the glycerol fermentation. This viewpoint is partially substantianted by the observation (2) that the extracellular lipase of Geotrichum candidum is completely inactive at pH 4.0 and that activity rapidly diminishes between pH 5.0 and pH 4.0. Specifically, lipase production has been reported to be influenced by the presence of certain buffers (3), carbohydrates (3, 10), vitamins (4), nitrogen sources (10), agar (10), fats (7), and various combinations of nutrients (9) in the cnlture medium. However, the varied responses of different microorganisms have no t permitted a unified concept of the influence of the components of the growth medium on microbial lipase production. The characteristics of the lipase (2) and some of the factors influencing the rate of liberation of water insoluble fat ty acids in cream by G. candidum (6) have been described recently. I t is the purpose of this report to present data pertaining to the influence of media components on the growth and lipase production by G. candidum.