Production of γ-Decalactone by a Psychrophilic and a Mesophilic Strain of the Yeast Rhodotorula aurantiaca

Abstract

Among 18 psychrophilic strains isolated near the Antarctic Station, the psychrophilic strain Rhodotorula aurantiaca A19 was selected for its ability of growth and gamma-decalactone production at low temperatures. The effects of temperature, initial pH, and castor oil concentration on the growth and gamma-decalactone production by a psychrophilic and a mesophilic strain of R. aurantiaca were investigated. The highest gamma-decalactone production in flasks (5.8 g/l) was obtained with the strain A19 at 14 degrees C and initial pH 7.0 in medium containing 20 g/l castor oil. On the other hand, these factors did not affect the production of gamma-decalactone by the mesophilic strain. In fermentor, a gamma-decalactone concentration of 6.6 g/l was reached with the strain A19, whereas a maximum of 0.1 g/l was obtained with the mesophilic strain. Our results suggest that the ability to synthesize gamma-decalactone is a particularity of the strain A19, since the mesophilic strain (no. 30645) produced small amounts, and the other (no. 31354) did not exhibit this property. It is, to our knowledge, the first report of gamma-decalactone production by R. aurantiaca and furthermore by a psychrophilic yeast strain. Moreover, the amount of gamma-decalactone obtained in fermentor with the strain 19 was on the order of concentrations usually described in patents.

The use of Macronet resins to recover γ-decalactone produced by Rhodotorula aurantiaca from the culture broth

“…Among these lactones, -decalactone was the most abundant [10]. In biotransformation medium, R. aurantiaca produced both -decalactone and its precursor 4-hydroxydecanoic acid.…”

“…We found that R. aurantiaca produced the form R--decalactone ((R)-(+)-4-hexylbutan-4-olide) ( Fig. 1) [10]. Nevertheless, no data were published on the isolation and puriWcation of -decalactone.…”

“…40267. The yeast was grown in glucose medium as previously described [10]. This yeast was used in the present study for -decalactone production.…”

The Utilization of Gum Tragacanth to Improve the Growth of Rhodotorula aurantiaca and the Production of γ-Decalactone in Large Scale

“…Cell dry weight was determined after the elimination of the fatty fraction of culture medium as described by Alchihab et al [12].…”

“…We have previously investigated the effects of temperature, initial pH and castor oil concentration on the production of γ-decalactone by the psychrophilic strain of the yeast Rhodotorula aurantiaca A19 [12]. The yeast was unable to grow at 20°C.…”