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Cyclosporin A was produced in a low foaming semi-synthetic media by carrageenan-entrappedTolypocladium inflatumin an airlift bioreactor with an external circulation loop. The cyclosporin A recovered by a single ethyl acetate extraction was essentially free of contaminating media and endogenously produced microbial products.

The methyl iodide salts of benzopyrano[2,3-b]pyridines have been ring-opened to give 3-(21-hydroxybenzoyl)-1-methyl-2(1H)-pyridinones in high yield.

rac-Mexiletine is an orally effective class 1b antiarrhythmic agent used to treat ventricular arrhythmias. In vivo experiments have demonstrated. It is predominantly metabolized by the liver with < 10% excreted as unchanged drug. The major mammalian metabolites have been identified as p-hydroxymexiletine (PHM) and hydroxymethylmexiletine (HMM). The purpose of our study was to determine whether the fungus Cunninghamella echinulata, which possesses a cytochrome P450 system analogous to that found in humans, could be used as a suitable in vitro model for studying the oxidative metabolism of rac-mexiletine. To accomplish this, a high performance liquid chromatographic assay was used that was capable of simultaneously quantifying the enantiomers of mexiletine, HMM, and PHM. Utilizing this procedure, it was demonstrated that C. echinulata stereoselectively converted rac-mexiletine into HMM (4% of added drug) and PHM (32% of added drug) after an incubation period of 50 hr. In addition, metabolite biosynthesis could be optimized by altering fermentation media components. Seven media values and seven pH values were evaluated. It was determined that a medium at pH 7.0 containing yeast extract and sucrose yielded optimal amounts of metabolites.