Chemo-enzymatic Synthesis of Rivastigmine Intermediate by Locally Isolated Soil Fungus Fusarium graminearum

Background: Biocatalytic reactions are known as a green technology, capable of delivering highly stereo-, chemo- and regioselective transformations that usually reduce the number of steps in a synthetic route. Objective: This work describes a process for the production of a key chiral intermediate N-ethyl-Nmethyl- carbamic acid-3-(1S-hydroxy-ethyl)-phenyl ester converted into chiral alcohol which can be further converted into rivastigmine. Methods: The fungi isolated from different soil samples by the soil dilution plate technique were screened for their ability to convert the selected intermediate. The selected organism is further grown under fermentation for gram scale conversion. Results: Among the different fungi isolated Fusarium graminearum selected for further study for reaction optimization and gram scale conversion of the ketone substrate. Conclusion: The reaction under fermentative condition for 48 hours at 30°C, pH 6 with agitation speed of 200rpm found to be optimal condition for the overall bioreduction process of the ketone employed in the study.