In these processes adequacy is a basic catalyst, there are some mechanisms but require zeolitic acid catalysis or similar materials, and the diffusional limitations are not the most suitable for reactions with fatty acids. In the studies and tests that have been performed is still very difficult to compete with sodium hydroxide, so the key point in this research is to optimize production methoxides.

yes, acid catalyst for esterification and than base catalyst for transesterification, in this order

All depends on free fatty acid (FFA) value of feedstock. If FFA values > 8%, then you should use acid catalyst followed by alkali catalyst. Otherwise, you can go for alkali catalyst directly.