Nonvolatile Organic Acids Produced by Sclerotinia Sclerotiorum In Synthetic Liquid Media

SUMMARY

Sclerotinia sclerotiorum (Lib.) D By. grew well and produced sclerotia on a glucose-salts liquid medium (pH 4.1-4.3 in stationary culture). Culture filtrates and mycelia + sclerotia were analyzed separately for organic acids by paper, silicic acid partition and thin-layer chromatography. Oxalic, succinic, malic, fumarie and glycolic acids were detected in the medium and cellular extracts. The pH of the filtrates reached a minimum of 3.4 and contained maximum amounts of the dicarboxylic acids after 2 weeks growth of S. sclerotiorùm. The quantity of these acids decreased and glycolic acid increased with longer incubation. Increasing the pH of the medium increased the amount of oxalic acid produced.

When S. sclerotiorum was grown on a mannitol-salts medium, growth of mycelia was depressed, no sclerotia were produced and the pH of culture filtrates increased. Only malic, oxalic and glycolic acids were found in culture filtrates. The maximum amount of malic acid was detected after 2 weeks of growth. Oxalic and glycolic acids increased slowly throughout the growth period. More total organic acid was produced on the glucose medium than on the mannitol medium.