Sl. no | Major factors | Acid catalyzed | Alkali catalyzed | Enzyme catalyzed |
1 | Yield of biodiesel | High, nearly 95% - 96% | High, nearly 99% | Relatively lower than alkali catalyst, around 90% |
2 | Downstream processing | Multi-step purification of end products | Multi-step purification of end products | None |
3 | Production cost | Little bit expensive as compared with alkali catalyzed process | Cheap, as catalysts are comparatively cost less | Synthesis of biocatalyst are expensive |
4 | Commercialization | Fully commercialized | Fully commercialized | Not yet commercialized |
5 | Waste water generation | Water washing is required to remove the acidic content in biodiesel | Saline and alkaline effluents need treatment, No waste water generation before discharge | No waste water generation |
6 | Reaction temperature | 100˚C | 60˚C - 80˚C | 20˚C - 60˚C |
7 | Presence of FFA’s in feed stock | No soap formation | Soap formation | Completely conversion into the methyl ester and no soap formation |