Inoculum effects on the production of gamma-linolenic acid by the shake culture of Cunninghamella echinulata CCRC 31840

The effects of using the fragmented mycelia as inoculum on the growth of and lipid and gamma-linolenic acid (GLA) production by the sporulation-deficient fungal strain Cunninghamella echinulata CCRC 31840 were examined in shake cultures. In a 5-day culture sown with 1.6% inoculum the biomass increased 51.5%. Its lipid content increased 69.0% when the floc massiveness of the inocullum was increased from 27,000 to 81,000 colony forming units per milliliter (CFU ml(-1)). This in turn resulted in a synergistic increase of GLA yield from 358 to 860 mg l(-1) whereas the GLA content of the lipid was virtually unaffected (11.2-13.4%). The maximum GLA yield of 1,349 mg l(-1) was obtained in a 5-day culture when the production medium was pitched at the 4% level with an inoculum preparation in which 1.0 g of mycelia have been fragmented to a floc massiveness of 83,000 CFU ml(-1)by vortexing for 4 min. (C) 1997 Elsevier Science Inc.