Use of a Doehlert factorial design to investigate the effects of pH and aeration on the accumulation of lactones by Yarrowia lipolytica.

E Escamilla García (1) , J.-M. Belin (1) , Yves Waché (1)

1 GPMA - Génie des Procédés Microbiologiques et Alimentaires

AIMS: To detect rate-limiting steps in the production of lactones by studying the combined effect of pH and aeration on their accumulation. METHODS AND RESULTS: A Doehlert experimental design was chosen to evaluate the accumulation of four lactones in the pH (3.5-7.3) and K(L)a (4.1 h(-1) to 26 h(-1)) experimental domain. The accumulation of gamma-decalactone was higher at pH around 5 and increased at low aeration reaching 496 mg l(-1) at pH 6.35 and K(L)a 4.5 h(-1). The specific accumulation increased at low aeration. The 3-hydroxy-gamma-decalactone accumulation was higher at low pH and high aeration conditions: 660 mg l(-1) at pH 4.4 and 26 h(-1). For dec-2-en-4-olide and dec-3-en-4-olide, lower amounts were reached (104 mg l(-1) and 66 mg l(-1), respectively). CONCLUSIONS: Although the accumulation of the four lactones should be related to catalytic steps requiring oxygen, the accumulation of gamma-decalactone was higher in low aeration conditions whereas the one of 3-hydroxy-gamma-decalactone was promoted for high aeration. Decenolides accumulate independently of pH or aeration. SIGNIFICANCE AND IMPACT OF THE STUDY: This study gives new insights into the catabolism of lipids, such as the role of co-factor regulation and the fact that the 3-hydroxylactone dehydration step is insensitive to pH or aeration.

Domaines: Biotechnologies

E Escamilla García, J.-M. Belin, Yves Waché. Use of a Doehlert factorial design to investigate the effects of pH and aeration on the accumulation of lactones by Yarrowia lipolytica.. Journal of Applied Microbiology, 2007, 103 (5), pp.1508-15. ⟨10.1111/j.1365-2672.2007.03379.x⟩. ⟨hal-00368186⟩