This study sought to identify the factors and conditions that affected production of the antifungal
glycolipid flocculosin by the biocontrol agent Pseudozyma flocculosa. For this purpose, different parameters known or reported to influence
glycolipid release in fungi were tested. Concentration of the start-up inoculum was found to play an important role in
flocculosin production, as the optimal level increased productivity by as much as tenfold.
Carbon availability and
nitrogen source (i.e., organic vs inorganic) both had a direct influence on the metabolism of P. flocculosa, leading to
flocculosin synthesis. In general, if conditions were conducive for production of the
glycolipid,
carbon availability appeared to be the only limiting factor. On the other hand, if yeast extract was supplied as
nitrogen source, fungal biomass was immediately stimulated to the detriment of
flocculosin synthesis. Unlike other reports of
glycolipid release by yeast-like fungi, inorganic
nitrogen starvation did not trigger production of
flocculosin. The relationship between the factors influencing
flocculosin production in vitro and the conditions affecting the release of the molecule by P. flocculosa in its natural habitat appears to be linked to the availability of a suitable and plentiful food source for the biocontrol agent.