This makes it very difficult to reuse the solid catalyst Sr2SiO4 , thus negating the major advantage of using the heterogeneous catalyst exist (Lam et al., 2010 ). These results indicate that the solid base catalyst, Sr2SiO4, seems to be less effective, when compared with NaOH, and unsuitable for use to catalyze the transesterification of the extracted microalgae oil under the current conditions.