Elicitor effects on Penicillium chrysogenum morphology in submerged cultures.

Changes in morphology and sporulation were investigated in liquid cultures of Penicillium chrysogenum P2 supplemented with carbohydrate oligosaccharides. Sodium alginate and locust-bean (Ceratonia siliqua) gum-derived oligosaccharides were used as elicitors. Spore germination was inhibited by the addition of OG (oligoguluronate) elicitor (30% inhibition when compared with control). Addition of any of the elicitors to stirred-tank cultures increased hyphal-tip numbers, clump area and spore counts. MO (mannan oligosaccharide) had the greatest effect on the parameters studied, followed by OM (oligomannuronate) and OG. Hyphal-tip numbers increased by 19, 29 and 47% with OG, OM and MO respectively. Average clump area in the presence of OG, OM and MO increased by 23, 32 and 59% respectively. A notable increase in spore numbers was observed in all the supplemented stirred-tank reactor cultures, with MO showing the highest enhancement.