PARTIAL-PURIFICATION AND CHARACTERIZATION OF A LIPASE FROM LACTOBACILLUS-PLANTARUM MF32

A lipase from Lactobacillus plantarum MF32 has been partly purified an d characterised. The apparent molecular weight of the lipase was estim ated to be approximately 75000. Isoelectric focusing resulted in two s eparate bands corresponding to pi values of 7 . 50 and 7 . 60, respect ively. The enzyme has been shown to contribute to sensory quality and reduced production time of fermented dry sausages. Temperature optimum was 37 degrees C with tributyrin as substrate and 41 degrees C with l ard as substrate, the overall activity of the lipase being about three times higher with tributyrin as substrate than with lard. Enzyme acti vity of the lipase was detectable at pH 4 . 5 and pH 12, with a pH opt imum around 9 . 3 for both substrates. The enzyme activity was only sl ightly affected by salt concentrations up to 5% NaCl. The temperature dependence of the enzyme as described by the Arrhenius equation with t ributyrin as substrate showed a Delta H-298(not equal) (inactivation) of 186 kJ/mol. The activation of the enzyme appears nonlinear with inc reasing temperature, probably due to changes in availability of the su bstrate with temperature.