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Enzymatic synthesis of organic molecules in alternative solvents

Final Report Summary - HIPENZO (Enzymatic synthesis of organic molecules in alternative solvents)

A growing awareness of the need for greener, more sustainable technologies has focused attention on the use of atom efficient catalytic methodologies for the manufacture of fine chemicals and pharmaceuticals. The use of alternative reaction solvents such as supercritical fluids or fluorous biphasic systems that are readily recycled, such as fluorous solvents and scCO2 has therefore become the focus of significant research that could circumvent the problems associated with many of the traditional volatile organic solvents. Thus novel and effective methods, enzyme recovery and recycling are receiving increasing attention. New approaches tackling these issues were objectives of this project.
Enzyme solubilisation in fluorous solvents and scCO2 by Hydrophobic Ion Pairing with perfluorinated surfactants was investigated. Various commercially available lipases capable of catalysing esterification and transesterification reactions were screened to select a lipase that could be efficiently ion paired with fluorinated surfactants. The complexation efficiencies of 60-70 % were achieved with several lipases giving 9-15 mg/ml [enzyme] in fluorous solvent. Two hydrophobically ion paired lipases Candida cylindracea and Pseudomonas cepacia demonstrated reasonable catalytic activity and good enantioselectivity towards the kinetic resolution of rac-1- phenylethanol in a perfluoromethylcyclohexane/hexane biphasic system. When HIP-lipases were employed for the ring-opening polymerisation of various lactones in fluorous biphasic system lipases Rhizopus arrhizus and Pseudomonas fluorescens were active and yielded polyesters. Further HIP-lipases were tested for the polycondensation polymerisation of polyesters. The ability to solubilise lipases in fluorinated solvents provided an opportunity to perform homogenous polymerisation of highly fluorinated monomers. Several hydroxyl-terminated fluorinated diols and fluorinated acids were examined in order to generate fluorinated polyesters with unique physical and chemical properties.