Lipolytic Activity

Almost all yeast related to cheese have esterase activity and are able to hydrolyze tributyrin (Fleet and Mian 1987; Hansen and Jakobsen 1997; Roostita and Fleet 1996a; van den Tempel and Jakobsen 1998). This applies for D. hansenii, K. lactis, S. cerevisiae and Y. lipolytica, C. catenulata and C. geotrichum, all showing esterase activity.

The reported results on the esterase activity of D. hansenii, K. lactis, and S. cerevisiae are contradicting (Besancon et al. 1992; Fleet and Mian 1987; Hansen and Jakobsen 1997; Roostita and Fleet 1996a; van den Tempel and Jakobsen 1998). But in general the activity is low. Tested in API-ZYM systems (Biomerieux, Macy l'Etoile, France), S. cerevisiae, D. hansenii, and K. lactis could hydrolyze the fatty acid with chain length of C:8, but not the fatty acid with a chain length of C:14 (Hansen and Jakobsen 2001). Lipolysis of long-chain fatty acids has been demonstrated for Y. lipolytica, C. catenulata, and C. geotrichum and the activity seems to be at the same level for the three yeasts (Roostita and Fleet 1996b; van den Tempel 2000).

Isolation of several intra and extracellular lipases from Y. lipolytica has been reported and the strong lipolytic activity of Y. lipolytica seems mainly to be due to extracellular lipases with optimal activity at pH 6-10 (Destain et al. 1997; Pereira-Meirelles and Rocha-Leao 1997). Some of the reported lipases are quite stable and are still active after 370 days at 5°C (Pereira-Meirelles and Rocha-Leao 1997). To demonstrate the extent of the lipolytic activity of Y. lipolytica, five strains were compared with five different strains of P. roqueforti with medium to high lipolytic activity. It was found that the lipolytic activity was twice the activity of the strongest lipolytic strain of P. roqueforti (van den Tempel and Jakobsen 2000). Investigations comparing lipolytic activity after growth under different condition showed that the lipolytic activity was depending on pH, temperature, and the growth media (Hansen and Jakobsen 1997; van den Tempel 2000).

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