Extended and enhanced production of swainsonine was achieved from fed-
batch fermentations of the fungus Metarhizium anisopliae. A complex me
dium based on oatmeal extract was intermittently fed with D-glucose an
d/or lysine. Swainsonine titres were improved eleven-fold and the dura
tion of production extended was from 240 to 550 hours compared with a
batch culture under the same conditions.