BIOTECHNOLOGYLETTERS Volume 17 No.3 (March 1995)pp.291-294 Received as revised 7th January P R O D U C T I O N O F C I T R I N I N BY V A R I O U S S P E C I E S O F M O N A S C U S P.J. BLANC*, M.O. LORET and G. GOMA DEpartement Cr6nie Biochimique et Alimentaire, UA-CNRS N ° 544, Institut National des Sciences Appliqu6es, Complexe Scientifique de Rangueil, F-31077 TOULOUSE Cedex, France. SUMMARY The production of citrinin by various Monascus species was determinated using various culture mediums and conditions. The maximal production was obtained in fermentor using M. ruber with concentrations of 380 rag/1. Since citrinin is a toxic product, it is essential that the production of red pigments as food additives from Monascus sp. avoid the occurrence of citrinin; so, we argue that some nitrogen sources are unfavorable to the production of citrinin. INTRODUCTION The fungal genus Monascus was discovered by van Tieghem (1884) and was known in Europe as a contaminant on cereals, starch and silage. In Asia, Monascus is used to prepare red mold rice as a natural food coloring matter and also as a food disinfectant (Went, 1895). Several authors (Wong and Bau, 1977; Wong and Koehler, 1981; Fink-Gremmels et aL, 1991) have shown the occurrence of antibacterial activities among crude pigments while others such as Ober and Kunz (1989) argue that some strains are unable to produce antibacterial compounds. Investigating the purification and identification of Monascus pigments regarding their acceptability as food additives by European Union, we have isolated monascidin A in various species of Monascus and identified it as citrinin (Blanc et al., 1995 in press), a nephrotoxic metabolite produced by various fungi (Wu et al., 1974). This was the first report of the occurrence of citrinin among metabolites produced by Monascus. This work has contributed to the characterization of the chemical structure of monascidin A and to identify one compound among the pigments of Monascus. As Monascus is being used as a food additive, it might be necessary to focus the investigations either on non citrinin producing species (Ober and Kunz, 1989) or on culture conditions unfavourable to citrinin production or at last, on detoxication of the pigments which could occur naturally (Barber et al., 1988) as really, some commercial colored preparations that we have analyzed didn't contain citrinin. MATERIALS AND METHODS Microorganism Species of Monascus, according to the new taxonomy proposed by Hawksworth and Pitt (1983) were used : Monascus ruber ATCC 96218, one albino strain isolated from the previous one, 3 obtained from culture collections namely Monascus purpureus CBS 109.07, Monascus pilosus CBS 286.34and Monascus purpureus DSM 1379 and one mutant strain isolated from Monascus purpureus CBS 109.07. Purity and identity of subcultures were verified. Media The strains were kept on slant culture composed of potato dextrose agar (PDA) Difco. Spores of the strains were prepared by growth on PDA slants for 10 days at 28"C. Culture conditions were established to analyze the effects of submerged and solid-state cullures on th production of citrinin. Three culture media were used : 291