Microbiological production of essential fatty acids

DETAILED DESCRIPTION We claim: 1.
A process for producing gamma-linolenic acid by (1) growing a diffused mycelial inoculum of Rhizopus arrhizus in a stirred, aerated nutrient medium containing a carbohydrate energy source and an inorganic nitrogen source at a carbon:nitrogen ratio of 20:1 to 60:1, maintained at a temperature of 25.
degree.
C.
.
+-.
2.
degree.
C.
and a pH of 3.
75 to 6.
25 in the presence of a foam breaker, until a gamma-linolenic concentration of at least 1.
0 g/liter of medium is reached, (2) harvesting the organism, and (3) extracting lipid containing the gamma-linolenic acid.
2.
The process according to claim 1, wherein the organism is Rhizopus arrhizus IMI 57412 (Mycological Institute, Kew).
3.
The process according to claim 1, wherein the pH is 6.
+-.
0.
2.
4.
The process according to claim 1, wherein aeration is at 0.
2 to 0.
5 volumes air/minute/volume of medium.




Description:
This invention relates to the microbiological production of essential fatty acids.
GENERAL During a current screening programme thirty-five strains of yeasts and fungi have been examined for .
gamma.
-linolenic acid production.
Data in Tables 1 and 2 show that neither yeasts nor higher fungi produce .
gamma.
-linolenic acid.
The C18:3 fatty acid produced by these fungi is .
alpha.
-linolenic acid and, with the exception of Aureobasidium pullulans, the quantities formed are small.
Members of the lower fungi, belonging to the order Mucorales, however are promising .
gamma.
-linolenic acid producers (see Table 3) and with the exception of Mucor hiemalis and Mortierella vinaceae this is the sole isomer produced.
Here lower fungi were grown in batch culture (2 liters) on a simple mineral salts medium comprising (g/l of distilled water), glucose 40 g, asparagine 2.
0 g, KH.
sub.
2 PO.
sub.
4 0.
5 g, MgSO.
sub.
4.
7H.
sub.
2 O 0.
25 g, thiamine hydrochloride 0.
005 g, at pH 7.
0 and 25.
degree.
C.
for 5-7 days before harvesting.
The culture had by this time achieved the stationary phase of growth and lipid accumulation was occurring