# Enzymatic Degumming of Soybean Oil for Raw Material Preparation in BioFuel Production
## 4 Discussion
Increasing the dose to 150-250 ppm was accompanied by only a slight decrease in the phosphorus level (to 7.8-8.7 ppm), but the economic feasibility of such an increase is questionable due to the increased costs of the enzyme and the increase in the level of FFA. On the other hand, reducing the dose to 50 ppm did not ensure a decrease in phosphorus to an acceptable level, which is explained by the insufficient number of active enzymes for complete hydrolysis of phospholipids. Thus, 100 ppm provides a balance between efficiency and economic feasibility. The temperature range of 53-65 \({}^{\circ}\)C was found to be the most favourable for the enzyme complex to work. The best results were achieved at a temperature of 56-58 \({}^{\circ}\)C,  
Figure 3: Scheme of using Purifine® 3G enzymes for degumming soybean oil: (**a**) Phospholipase C work, conversion of phospholipids to diglycerides and phosphates; (**b**) Phospholipase A2 work, conversion of phospholipids to lysophospholipids and free fatty acids. when the obtained phosphorus level was 10.0 ppm, and FFA remained at the level of acid value 0.86 mg KOH/g oil. Lowering the temperature to 50 \({}^{\circ}\)C reduced the enzyme activity, and increasing it above 65 \({}^{\circ}\)C caused thermal destruction of the enzyme and led to an increase in FFA (Figure 3). The pH level is an important parameter that determines the conformation of the enzyme and, consequently, its activity. The best results were obtained at pH 6.9-7.1, when the resulting phosphorus level was 9.5 ppm, and FFA remained at the level of acid value 0.88 mg KOH/g oil. Deviation from this pH range led to a decrease in the efficiency of degumming, which confirms the importance of maintaining stable process conditions (Figure 4). The amount of added water affects the formation of the humic phase and the efficiency of removal of hydrolysis products. At a water concentration of 2.5% of the oil mass, the obtained phosphorus level was 9.1 ppm, and FFA remained stable (acid value 0.87 mg KOH/g oil). Although increasing the water content to 5% further reduced the phosphorus level, it led to an increase in wastewater volumes, which requires additional costs for treatment systems, making this option less environmentally friendly. The optimal duration of enzymatic degumming was 120 min. During this period, the enzymatic complex ensured complete hydrolysis of phospholipids, reducing phosphorus to 9.2 ppm and changing the FFA content to an acid value of 0.84 mg KOH/g oil. Extending the time to 180 min and more slightly improved the results but was accompanied by an increase in FFA due to secondary reactions of triglyceride cleavage. Considering the increase in production costs with an increase in enzymatic degumming time, the optimal reaction period is exactly two hours. The Purifine(r) 3G enzyme action diagram (Figure 3) demonstrates how the synergy of two enzymes creates optimal conditions for highly efficient degumming. This process not only improves the quality of the final product but also ensures economic feasibility and environmental responsibility in industrial production. A comparison of the degumming efficiency using Purifine(r) 3G and methods described in the literature, in particular using the Quara LowP and Lecitase Ultra enzymes, demonstrates a number of fundamental differences in mechanisms of action and technological requirements. Thus, the Quara LowP and Lecitase Ultra enzymes are phospholipipases A\({}_{1}\), the action of which is based on the conversion of non-hydrated phospholipids (in particular, phosphatidylcholine) into hydrated forms, which can subsequently be removed. However, an important condition for their effective action is the preliminary acidification of the oil with phosphoric acid (85%) to a pH level of 3.8-5.5, which requires additional technological stages--acidity regulation, neutralization, introduction of buffers, and significant consumption of reagents.