Effect of tweens on the production of ergot alkaloids by Aspergillus fumigatus.

Tween 80, which caused increased biomass formation, also produced the highest increase in the uptake rate of all components of the medium. The fatty acid components of the respective Tweens, i.e. palmitic acid (Tween 40), stearic acid (Tween 60), and oleic acid (Tween 80), have no effect either on alkaloid production or on substrate uptake. The fatty acid composition was different in the cell membrane of the culture supplemented with Tween 60 and facilitated the transport of metabolites into the cells.