Abstract
A gamma linolenic acid (GLA, cis-6,9,12-Octadecatrienoic acid) producing fungus was isolated and identified for the first time as Rhizopus nigricans, labeled as SSSD-8. The alteration of carbon and nitrogen sources on the production of GLA by Rhizopus nigricans SSSD-8 was examined in flask cultures for two separate media. The cultivation conditions were optimised for GLA production by appropriate selection of carbon and nitrogen sources and their concentrations, temperature, time of incubation, and pH. On an identical weight basis, soluble starch is the best carbon source and urea the most preferred nitrogen source for GLA yield irrespective of the media composition. A maximum GLA yield of about 1640 mg/L was obtained for Rhizopus nigricans SSSD-8 when incubated at 30°C and at pH 5.5 in the medium containing 15% (w/v) potato extract, 15% (w/v) soluble starch, 0.5% (w/v) yeast extract, and 0.2% (w/v) of urea.
