Other Transesterification Technologies
Acid catalysed transesterification
The most intensively used acid catalysts in industrial transesterification are HCl, H2SO4 and BF3. It is advantageous to use acid to catalyse low-cost lipid sources with high free fatty acid (FFA) content, as these acids are two-way catalyst that stimulates both esterification of FFA and transesterification[8]. When used in combination of other catalysts, they usually applied at the beginning of the process to reduce FFA content in stock, which facilitate follow-on high efficient reaction[9]. Under acid catalysing, the reaction speed is around 4,000 times slower than base-catalysed reaction due to reaction kinetics limitation. Acid catalyst also requires high-temperature …show more content…
Low operation condition requirements (low temperature and low pressure) and faster reaction rate are the two most distinct advantages, and its operational cost is lower than acid and enzyme catalysed reaction[3]. The saponification reaction is the major drawback with base catalyst and it is hard to be eliminated completely, hence algal oil with higher than 5% FFA is not recommended for direct base-transesterification[10]. Furthermore, the saponification problem lead to increased solubility of FAMEs in glycerol hence additional separation and purification are needed, which brings in extra …show more content…
This design bypasses the need for enzyme extraction and purification, which reduces the operation cost and complexity[2]. With the protection of the cell, the enzyme production in this system is also robust to harsh environmental condition such as high surrounding water content and acidic/basic condition [14]. However, the alcohol present in transesterification is toxic to immobilised cells. Therefore, scientists are still seeking for an ideal organism cell who has the minimum limitations to the technical hurdles[2].
To summarise, adsorption-immobilised enzymatic transesterification is distinct in enzyme-recycling, toxic waste control and high production efficiency. Like other enzyme-based method, cost is the major factor that limit its massive application. The advantages and disadvantages of each transesterification methods are tabulated in the following page for comparison. Table 1. Strength and Limitations for Different Transesterification Methods
Method Advantages Disadvantages
Acid Catalysed suitable for solution with high FFA contents require high operation temperature and pressure
low reaction
Acid catalysed transesterification
The most intensively used acid catalysts in industrial transesterification are HCl, H2SO4 and BF3. It is advantageous to use acid to catalyse low-cost lipid sources with high free fatty acid (FFA) content, as these acids are two-way catalyst that stimulates both esterification of FFA and transesterification[8]. When used in combination of other catalysts, they usually applied at the beginning of the process to reduce FFA content in stock, which facilitate follow-on high efficient reaction[9]. Under acid catalysing, the reaction speed is around 4,000 times slower than base-catalysed reaction due to reaction kinetics limitation. Acid catalyst also requires high-temperature …show more content…
Low operation condition requirements (low temperature and low pressure) and faster reaction rate are the two most distinct advantages, and its operational cost is lower than acid and enzyme catalysed reaction[3]. The saponification reaction is the major drawback with base catalyst and it is hard to be eliminated completely, hence algal oil with higher than 5% FFA is not recommended for direct base-transesterification[10]. Furthermore, the saponification problem lead to increased solubility of FAMEs in glycerol hence additional separation and purification are needed, which brings in extra …show more content…
This design bypasses the need for enzyme extraction and purification, which reduces the operation cost and complexity[2]. With the protection of the cell, the enzyme production in this system is also robust to harsh environmental condition such as high surrounding water content and acidic/basic condition [14]. However, the alcohol present in transesterification is toxic to immobilised cells. Therefore, scientists are still seeking for an ideal organism cell who has the minimum limitations to the technical hurdles[2].
To summarise, adsorption-immobilised enzymatic transesterification is distinct in enzyme-recycling, toxic waste control and high production efficiency. Like other enzyme-based method, cost is the major factor that limit its massive application. The advantages and disadvantages of each transesterification methods are tabulated in the following page for comparison. Table 1. Strength and Limitations for Different Transesterification Methods
Method Advantages Disadvantages
Acid Catalysed suitable for solution with high FFA contents require high operation temperature and pressure
low reaction