Effects of Non-ionic Surface Active Agents on Riboflavin Production by Eremothecium ashbyii

Abstract

Addion of non-ionic surface active agent, Tween 80,into a growth medium consisting of glucose, peptone, yeast extract and salts caused an extreme increment in riboflavin yield by Eremothecium ashbyii. Riboflavin production was fluctuated by supply with various surfactants having different ratios of hydrophilic and lipophilic groups. Constituents of the agents such as sorbose and fatty acids inhibited riboflavin formation. Lack of yeast extract from the medium resulted in no more stimulation of riboflavin synthesis by Tween 80. Conversely, when glucose lacked in the medium, the stimulatory effect depended only upon existence of peptone as an organic nutrient. Yeast extract was exchangable in the presence of Tween 80 with inositol, thiamine, biotin and purine bases. Xanthine and guanine were most available to augment riboflavin yield. Mechanisms of the effect of Tween 80 on ribofla-vinogenesis were discussed in connection with changes in nutrient-environment of the fungus.