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

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