To determine the optimum pH of the reaction, assay of lipase
activity were carried out using the MMT buffer at pH 3e9. MMT
buffer was obtained by mixing DL-malic acid, MES and Tris base in
the molar ratios 1:2:2. The pH was adjusted to 3 by adding the
appropriate amount 10 M HCl, the pH 9 adding the appropriate
amount 10 M NaOH. A wide variety of pH values in the 3e9 pH
range was reached by mixing high and low pH stock solutions.