Chitosan hydrogels: A new and simple matrix for lipase catalysed biosyntheses

Lipase from Mucor miehei was immobilized on chitosan hydrogels without using any activation agent. These low-cost and easy to prepare lipase-containing hydrogels could be considered as novel solid-phase biocatalysts for use in organic media. When they were applied as biocatalysts towards the model esterification reaction of propyl laurate synthesis they showed an optimum operation temperature at 30 °C and maintained a high catalytic activity in various non-polar organic solvents. The higher initial esterification rates were obtained when biocatalysis took place in branched hydrocarbons where the initial rates recorded were twice the ones observed for straight hydrocarbons, being 0.22 mM/min in isooctane and 0.11 mM/min in hexane, respectively. The novel catalyst presented excellent reusability, with only 10% loss of activity after 12 uses, which is even higher than the one obtained by lipase-containing chitosan beads prepared with a cross-linker. Moreover, enzyme superactivity was evident for several runs.