SWAINSONINE PRODUCTION FROM BATCH CULTURES OF METARHIZIUM-ANISOPLIAE IN STIRRED-TANK REACTORS

Metarhizium anisopliae was cultured batchwise in stirred-tank reactors using complex media selected for the enhanced production of swainsoni ne. A swainsonine concentration of 40 mg l(-1) produced at 170 h was m ore than double that obtained from shaken-flask cultures in the same m edium after the same period of time. When conventional Rushton turbine impellers were employed, detrimental surface cake formation was obser ved after 90 h in the fermenters, resulting in nonhomogenous cultures and reduced productivity. Improved culture homogeneity and swainsonine production were achieved through alteration of the impeller type and position in the reactor. Further improvements were obtained by the ado ption of controlled aeration strategies.