초록
The catalytic performance of whole Mucor circinelloides URM 4182 cells immobilized in polyurethane foam particles was assessed for the ethanolysis of different vegetable oils, including andiroba (Carapa guianensis), coconut (Cocos nucifera), jatropha (Jatropha curcas), macaw palm (Acronomia aculeata), and palm tree (Elaeis guineensis). In a typical batch run, the immobilized cells were added at a vegetable oil-to-ethanol molar ratio of 1:8 using tert-butanol as the solvent. Under these conditions, the biocatalyst showed consistent selectivity by producing the corresponding ester from each fatty acid. The highest yield was achieved in the ethanolysis of coconut (97%) and macaw palm (95%) oils whose fatty acid profiles showed predominant concentrations of lauric acid. These results suggested high specificity of intracellular lipases to convert saturated fatty acids into their respective ethyl esters. The ethanolysis activity of the immobilized cells was also assessed at different space times (60-80h) in a continuous packed-bed reactor using coconut oil as the feedstock. Better reactor performance was found at space time of 80h. In this condition, 92.7+/-1.5% of the fatty acids present in the coconut oil were converted into the corresponding ethyl esters. The average volumetric productivity was 3.5+/-0.7mg<SUB>ester</SUB>g<SUP>-1</SUP><SUB>biocatalyst</SUB>h<SUP>-1</SUP> with no significant reduction in the reactor efficiency during 25 days.