Producing biodiesel using whole-cell biocatalysts in separate hydrolysis and methanolysis reactions

This research examined the effect of using separate hydrolysis and methanolysis reactions for biodiesel production using a whole-cell biocatalysts derived from Rhizopus Oryzae (ATCC 10260). Biodiesel yield from separate hydrolysis and methanolysis was compared to transesterification reactions where both hydrolysis and methanolysis reactions occur in the same reactor. All reactions were conducted at room temperature. The effect of substituting ethanol for methanol was also studied. Separating the hydrolysis and methanolysis reactions did not significantly increase biodiesel yields; however, this approach successfully converted about 99% of triglycerides into fatty acid methyl esters (FAME) and free fatty acids (FFA). Use of ethanol in place of methanol did not significantly improve the biodiesel yield. However, there is evidence that ethanol may either esterify FFA more quickly than methanol, or result in a more stable ester. The best biodiesel yield was about 90% when a transesterification reaction using methanol was followed by one hydrolysis and one ethanolysis reaction; however, this is only slightly higher than the 88% biodiesel yield of two transesterification reactions in series (using methanol as alcohol).