The presence of impurities in biodiesel feedstock can damage the catalyst and reduce the effectiveness and yield of the process. Thus, degumming is a critical pretreatment step in biodiesel production for removing phospholipids (“gums”) from crude vegetable oil.
Traditional degumming involves water, acids, or chemical neutralization to remove impurities from biodiesel feedstock. However, the creation of chemical waste and lower oil recovery can reduce the efficacy of the process. As a result, enzyme-based degumming is emerging as a sustainable, efficient alternative to traditional chemical methods.
Here we compare enzymatic and conventional degumming processes, explaining their impact on efficiency, cost, and biodiesel yield.
What Is Degumming and Why Does It Matter in Biodiesel Production
Degumming refers to the removal of phospholipids and other impurities from crude vegetable oil before using it to make biodiesel. These impurities can interfere with the transesterification process, making the degumming process an essential part of biodiesel production.
Vegetable oils, used for biodiesel production, come from soybean, canola, palm, and sunflower oils. These contain impurities (called gums), whether they are derived from screw pressing or solvent extraction. These gums usually contain phospholipids, sugars, nitrogen compounds, and entrained oils. When they come into contact with water, they get hydrated and turn into oil-insoluble micelles.
During biodiesel production, the process followed is:
Vegetable Crude oil → Degumming → Neutralization → Transesterification → Biodiesel.
The role of the degumming process in improving how biodiesel is made is as follows:
- Increases the efficiency of the transesterification process, thus increasing yield.
- Improves catalyst performance by preventing its deactivation.
- Improves fuel purity and stability, and prevents the formation of deposits in the engine.
Overview of Traditional Degumming Methods
Traditionally, degumming was performed via one of the three following processes:
|
Method |
Process Summary |
Drawbacks |
| Water Degumming | Uses hot water to hydrate and remove hydratable phospholipids | Inefficient for non-hydratable gums |
| Acid Degumming | Uses citric or phosphoric acid to convert non-hydratable gums | Corrosive and creates chemical waste |
| Chemical Neutralization | Adds alkali to remove residual acids and gums | High soap formation, lower oil recovery |
Table 1: Traditional Degumming Processes and Their Drawbacks
Enzymatic Degumming: A Modern Biocatalytic Approach
To improve on the drawbacks of traditional degumming methods, the biocatalytic enzymatic degumming process was developed. This method uses phospholipase enzymes (e.g., PLA1, PLC) to hydrolyze phospholipids into water-soluble lysophospholipids and fatty acids. This improves oil yield and produces oils with low phosphorous content with minimal chemical use.
Using phospholipase compounds, the operating conditions can be reduced to mild temperatures (55 to 75°C) and stable catalytic ability in a 3.0 to 4.9 pH range for the degumming process. This effectively reduces chemical inputs, minimizes wastewater generation, and increases oil recovery. Thus, it broadens the operational parameters, offers faster reaction rates, and lowers the operational costs.
Tabular Comparative Analysis: Enzymatic vs Traditional Degumming
A simple comparison between the enzymatic degumming process and the traditional degumming is as follows:
|
Parameter |
Traditional Degumming |
Enzymatic Degumming |
| Process Temperature | 70 – 90°C | 50 – 75°C |
| Chemical Use | Acids/alkalis required | Minimal (enzyme only) |
| Oil Loss | 1.5 – 3% | <0.5% |
| Phosphorus Reduction | 50 – 90 ppm | <10 ppm |
| Environmental Impact | High waste generation | Eco-friendly and biodegradable |
| Operational Cost | Lower upfront, higher waste disposal | Slightly higher enzyme cost, long-term savings |
| End Biodiesel Yield | Moderate | High, due to purer oil feedstock |
Table 2: Comparison Between Traditional and Enzymatic Degumming Processes
How Enzymatic Degumming Improves Biodiesel Quality and Efficiency
In comparison to traditional degumming methods, enzymatic degumming is preferred due to the following reasons:
- Enables better transesterification due to cleaner oil feedstock.
- Facilitates the fast conversion of phospholipids into lyso-phospholipids and free fatty acids.
- Reduces catalyst poisoning and soap formation.
- Offers stable performance under a range of temperatures and pH variations.
- Reduces dependency on chemicals (citric acid and caustic soda).
- Enhances biodiesel purity, oxidative stability, and glycerin quality.
- Improves oil yield and lowers operational expenditure.
- Compatible with a range of vegetable oils like soybean, rapeseed, sunflower, and mixed feedstock oils.
Sustainability and Economic Benefits
Additionally, enzymatic degumming is a far more sustainable process compared to its alternatives due to its lower chemical consumption and reduced environmental footprint. The sustainability and economic benefits that biodiesel production gains from degumming are as follows:
- Less wastewater treatment is required.
- Less industrial waste is generated.
- Higher oil recovery leads to better profit margins.
- Ideal for large-scale refineries and green-certified plants.
Challenges and Future Scope
Despite several benefits, enzymatic degumming in biodiesel production faces certain challenges:
- High enzyme cost and stability at an industrial scale.
- Need for optimized reaction times and reactor designs.
Further, the following future trends are expected to be observed for enzymatic degumming:
- Immobilized enzyme systems for reuse.
- Integration of the process into continuous biodiesel production lines.
- Advancements in genetically engineered phospholipases.
Thus, it is expected that the enzymatic degumming process will gain both efficiency and popularity with widespread adaptation in the future.
Wrapping Up
Enzymatic degumming offers a cleaner, more efficient alternative to traditional chemical methods in biodiesel production. With higher oil yields, reduced waste, and enhanced fuel quality, it represents the future of sustainable biofuel processing.
Ensuring an Efficient Biodiesel Production Process
Looking to upgrade your biodiesel process with greener, more efficient technology? Explore enzymatic degumming solutions and discover how biocatalysis can revolutionize your production efficiency.