Submerged Fermentation of Penicillium paxilli Biosynthesizing Paxilline, a Process Inhibited by Calcium-induced Sporulation

Abstract

A submerged fermentation process for the production of the tremorgenic mycotoxin paxilline by Penicillium paxilli has been developed. The fungus did not sporulate and accumulated paxilline to 1.5 % (w/w) in freeze-dried cells within 6 d in a 60 1 stirred fermenter. Induction of extensive differentiation of conidiophores and profuse sporulation by adding 2% (w/v) CaCl,. 2 H 2 0 to the medium at batching reduced paxilline yield by 97 %. Paxilline biosynthesis occurred when the glucose in the medium had been exhausted, implying that carbon catabolite repression may be involved in the biosynthesis of this alkaloid, even when calcium-induced sporulation inhibits or delays the onset of paxilline biosynthesis. Sporulation-induced inhibition of indole-terpenoid alkaloid biosynthesis in P. paxilli contrasts with the situation in some other penicillia elaborating indole alkaloids and allows disassociation of aspects of secondary metabolite biosynthesis from growth-associated differentiation, which formerly seemed to be linked.

Surface hydrophobicity, viability and efficacy in biological control of Penicillium oxalicum spores produced in aerial and submerged culture

“…1998), and calcium‐induced sporulation is known to inhibit the production of secondary metabolites in other Penicillium spp. (Ibba et al . 1987).…”

The role of tryptophan as a biosynthetic precursor of indole-diterpenoid fungal metabolites: Continuing a debate

“…A fermentation system for studying the indole source in lolitrem biosynthesis in the context of its tryptophan-derived co-metabolite ergovaline (5) would be attractive, but is probably not yet available in sufficient product yield. However, several model systems are available in addition to that for nodulisporic acid (7) in the particular Nodulisporium sp., namely paxilline (11) alone in P. paxilli (Ibba et al, 1987), penitrem A (2) and pennigritrem (12) together in P. nigricans (Penn et al, 1992), penitrem A (2) and nigrifortine (18) together in P. nigricans (Laws and Mantle, 1985;Mantle et al, 1984), and janthitrems alone in P. janthinellum (Penn et al, 1993). Experiments conducted with 13 C and 14 C in parallel could also aid clarification of tryptophan's role as an indole source.…”

Experimental Constraints in the Study of the Biosynthesis of Indole Alkaloids in Fungi

“…Penicilliumpaxilli Bain. was as previously described (Ibba et al, 1987) and the strain of Clauicepspaspali Stevens et Hall used was ATCC 13892. Cultures were maintained on potato dextrose agar.…”