Adaptative or constitutive nature of the enzymes involved in the oxidation of n-hexadecane into palmitic acid by Candida lipolytica
✍ Scribed by E. J. Nyns; J. P. Auquière; A. L. Wiaux
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 483 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0233-111X
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✦ Synopsis
Yeasts have been known to giow at the expense of n-paraffins for a number of years (TAUSSON 1939). It is generally accepted that the alkane is mainly metabolized through the corresponding primary alcohol, aldehyde and fatty acid. The enzymes involved in this pathway are adaptative or constitutive depending upon the microorganism studied (VAN DER LINDEN and THIJSSE 1956).
Candida lipolytica is one of the most extensively investigated hydrocarbon assimilating microorganisms. Whether the enzymes, by which the yeast oxidizes n-hexadecane into palmitic acid, are constitutive to the microbial cell or formed adaptatively upon exposure to the substrate, has remained open to question, and was investigated by respirometric experiments in a WARBURG apparatus using resting cells of C. lipolytica grown on 1 yo n-hexadecane, cetylalcohol, palmitaldehyde, palmitic acid or glucose. 5 1969 373-380
JIuterial and methods
Cultures: Candida Zipolytica, strain 599 from the Centraal Bureau voor Schimmelkulturen (C. B. S., Delft, Neth.) was maintained, grown on either 1% n-hexadecane or glucose, and harvested in the middle of its logarithmic phase of growth, as described earlier (NYNS et al.
1967).
The same procedure was used when cetylalcohol, palmitaldehyde or palmitic acid served as sole source of carbon and energy. I n these cases, 100 ml of the liquid growth medium were prepared as follows: 1 g of the carbon source and 89 ml distilled water were steam-sterilized a t 120 "C for 20 min. A tenfold concentrated aqueous solution of Yeast Nitrogen Base (DIFCO) was filter-sterilized through a membrane of 0.22 p diameter (Milli-