Lipase-catalysed synthesis of natural ethanol esters: effect of water removal on enzyme reutilisation

Lipase-catalysed synthesis of ethanol esters using natural substrates is pr esented. Initial substrate concentrations, optimised through an experimenta l design, were 0.8 mol dm(-3) lauric acid and 0.58 mol dm(-3) ethanol, with an initial esterification rate (r(0)) of 17.13 mmol dm(-3) min(-1). Two di fferent water removal systems were compared: a cooling exchanger in the rea ctor headspace and a vacuum-based system. The best results were obtained wi th the second system. After six consecutive operations with the same enzyme , no loss of activity was observed. The yields obtained in all the runs wer e greater than 90%. Using the same approach three different natural esters (ethyl laureate, ethyl myristate and ethyl palmitate) were synthesised at 0 .9 dm(3) scale. Similar results were obtained in all three cases, with chem ical yields always being greater than 90%. (C) 2000 Society of Chemical Ind ustry.