Stimulatory effect of plant oils and fatty acids on the exo-biopolymer production in Cordyceps militaris

The exo-biopolymer production and mycelial growth were substantially increased (almost tripled) by supplementation of certain vegetable oils into the medium. In particular, sunflower oil at the level of 2% led to a significant increase in exo-biopolymer concentration from 2.3 to 7.5 g/l, while the addition of 4% olive oil dramatically increased mycelial biomass from 5.8 to 19.0 g/l. To elucidate which components in those oils increased biopolymer production, effects of major fatty acids that constitute plant oils were further studied. Among fatty acids tested, addition of 2% oleic acid and palmitic acid markedly stimulated the biopolymer production (enhancement factors were 6 and 5.5, respectively), whereas linoleic acid drastically suppressed both mycelial growth and exo-biopolymer production.