Resolution of 1,2-epoxyhexane by Rhodotorula glutinis using a two-phase membrane bioreactor

Large-scale resolution of epoxides by the yeast Rhodotorula glutinis was de monstrated in an aqueous/organic two-phase cascade membrane bioreactor. Due to the chemical instability and low solubility of epoxides in aqueous phas es, an organic solvent was introduced into the reaction mixture in order to enhance the resolution of epoxide. A cascade hollow-fiber membrane bioreac tor was used (1) to minimize the toxicity of organic solvents towards the e poxide hydrolase of R. glutinis, and (2) to remove inhibitory amounts of fo rmed diol from the yeast cell containing aqueous phase. Dodecane was select ed as a suitable solvent and 1,2-epoxyhexane as a model substrate. By use o f this membrane bioreactor, highly concentrated (0.9 M in dodecane) enantio pure (>98% ee) (S)-1,2-epoxyhexane (6.5 g, 30% yield) was obtained from the racemic mixture.