[Toxinogenic moulds in silage. II. -- In vitro kinetics of patulin and byssochlamic acid biosynthesis by Byssochlamys nivea Westling in liquid medium (author's transl)].

A strain of Byssochlamys nivea (E 70), isolated from an silage and in pure culture, produces two mycotoxins (patulin and byssochlamic acid). A comparison of the toxinogenesis of this fungic species on eight culture media (table I) shows that maximal patulin concentration (816 p.p.m.) is obtained on Czapek's liquid medium (Difco) enriched with yeast extract (2 p. 1000) and glucose (8 p. 1 000) ; maximal byssochlamic acid concentration (390 p.p.m.) is obtained on wet corn grains (80 p. 100 of water). The lowest amounts are found on soya meal (patulin : 30 p.p.m.; byssochamic acid : 15.2 p.p.m.). Study of patulin and byssochlamic acid biosynthesis kinetics on liquid medium at 26 degrees C reveals that maximum patulin is obtained on day 9 of culture. It precedes maximum growth of the mould, and appears to coincide with phialospores formation. Maximum production of byssochlamic acid is obtained after 60 days of culture, that is, during mould autolysis phase. Kinetics of these mycotoxin productions should be studied in silage storage conditions.