A mixture of related metabolites (denoted OR-1) was isolated from the fermentation broth of Penicillium funiculosum together with mitorubrinic acid. Structurally OR-1 is glyceric acid esterified with C14-C18 fatty acids. Steady-state studies revealed that OR-1 behaved like an uncompetitive trypsin inhibitor with Ki 17.6 mumol/L.

The optimum conditions for the production of (-)-mitorubrinic acid by mutant strain of Penicillium funiculosum CCM F-8080 were examined in shaken flask cultures. The highest production of this metabolite was achieved in a medium with glucose as the sole carbon source and (NH4)2HPO4 as the nitrogen source. The most suitable concentrations of the given sources for production of (-)-mitorubrinic acid are 80 g/l glucose and 2 g/l (NH4)2HPO4 (maximal production, 814.9 mg/l). We also observed the influence of concentration of L-phenylalanine and inorganic phosphate in culture medium on the production of (-)-mitorubrinic acid. The biological activity of mitorubrinic acid as trypsin inhibitor was determined (IC50 41.05 mumol/l).

The optimum conditions for the production of (–)‐mitorubrinic acid by mutant strain of Penicillium funiculosum CCM F‐8080 were examined in shaken flask cultures. The highest production of this metabolite was achieved in a medium with glucose as the sole carbon source and (NH4)2HPO4 as the nitrogen source. The most suitable concentrations of the given sources for production of (–)‐mitorubrinic acid are 80 g/l glucose and 2 g/l (NH4)2HPO4 (maximal production, 814.9 mg/l). We also observed the influence of concentration of L‐phenylalanine and inorganic phosphate in culture medium on the production of (–)‐mitorubrinic acid. The biological activity of mitorubrinic acid as trypsin inhibitor was determined (IC50 41.05 μmol/l).