Use of a Doehlert factorial design to investigate the effects of pH and aeration on the accumulation of lactones by Yarrowia lipolytica.
OBJECTIVE
To detect rate-limiting steps in the production of lactones by studying the combined effect of pH and aeration on their accumulation.


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.


CONCLUSIONS
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.
García
E Escamilla
EE
Laboratoire de Microbiologie, UMR UB-INRA 1232, IFR 92, ENSBANA, 1, esplanade Erasme, 21000 Dijon, France.
Belin
J-M
JM
Waché
Y
Y
D005163:Factor Analysis, Statistical; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007783:Lactones / Q000378:metabolism*; D009812:Odorants; D010100:Oxygen / Q000378:metabolism; D012277:Ricinoleic Acids / Q000378:metabolism; D025062:Yarrowia / Q000378:metabolism*
D007783:Lactones; D012277:Ricinoleic Acids; C109757:decan-4-olide; D010100:Oxygen