# Enzymatic Degumming of Soybean Oil for Raw Material Preparation in BioFuel Production
## 4 Discussion
As a result of their transformation during the degumming process, a complex multicomponent water-lipid emulsion is formed, containing significant concentrations of hydrolysis products such as inositols, glycerophosphates, lysophospholipids, diglycerides, and amphiphilic residues [1; 32; 33]. Additionally, the phase includes denatured proteins, non-emulsified free fatty acids, and soluble phosphorus-containing compounds. A preliminary qualitative analysis of the rubber phase was carried out using infrared (IR) spectroscopy, which confirmed the presence of key functional groups: amine groups(1540 cm\({}^{-1}\)), phosphate residues (1240-1260 cm\({}^{-1}\)), carbonyl groups (1740-1760 cm\({}^{-1}\)), and alkyl chains of fatty acids (3008-3010 cm\({}^{-1}\); 2850-2920 cm\({}^{-1}\)). Based on the obtained data, the gum phase can be preliminarily assessed as a potentially suitable medium for cultivating microorganisms, particularly those requiring sources of phosphorus, nitrogen, and carbon. However, due to the absence of completed quantitative elemental analyses and microbiological tests, these statements are currently regarded as prospective hypotheses requiring further confirmation in subsequent stages of the research. At the current stage, samples of the obtained sludge have been transferred for a separate study aimed at evaluating its potential as a nutrient medium for the cultivation of biosurfactant-producing microorganisms. This approach opens prospects for the circular utilization of the by-product, which in the future may increase the economic efficiency of enzymatic degumming and reduce its environmental impact. The results of the study showed that the biofuel contains such fatty acid methyl esters as Palmitic acid, methyl ester (C\({}_{17}\)H\({}_{34}\)O\({}_{2}\)), Linolenic acid, methyl ester (C\({}_{19}\)H\({}_{32}\)O\({}_{2}\)), Linoleic acid, methyl ester (C\({}_{19}\)H\({}_{34}\)O\({}_{2}\)), Oleic acid, methyl ester (C\({}_{19}\)H\({}_{36}\)O\({}_{2}\)), Stearic acid, methyl ester (C\({}_{19}\)H\({}_{38}\)O\({}_{2}\)) and Isolineic acid, methyl ester (C\({}_{19}\)H\({}_{34}\)O\({}_{2}\)). Palmitic acid, methyl ester and Stearic acid, methyl ester, which belong to saturated fatty acids, were identified on the chromatogram with retention times of 8.193 min and 8.882 min, respectively. Oleic acid, methyl ester, which is a monounsaturated fatty acid, exhibited the highest peak intensity at 8.814 min, while polyunsaturated fatty acids such as Linolenic acid, methyl ester, Linoleic acid, methyl ester, and Isolineic acid, methyl ester, appeared at 8.675 min, 8.725 min, and 9.136 min, respectively (Figure 5 and Table 7). Mass spectrum analysis of the fraction with a retention time of 8.814 min revealed characteristic fragments with masses \(m/z\) 55; 69; 74; 83; 97; 96; 84; 41; 98; 87, confirming the identification of Oleic acid methyl ester (Figure 6). Similar spectra were recorded for all components of the biofuel, and FAME was confirmed and identified in the composition of the biofuel. The total content of fatty acid esters was 97.2%. Characteristic fragments with masses \(m/z\) of the main products of the transesterification reaction are listed in Table 7.  
The overall composition of the fraction is characterized by a balanced ratio of saturated fatty acids (19.88%), monounsaturated (35.65%) and polyunsaturated (26.14%). In addition, 18.33% are methyl esters of fatty acids with a content below 2.00%. A high proportion of methyl oleate indicates the stability of the fraction, while the presence of saturated acids, such as Palmitic acid, methyl ester and Stearic acid, methyl ester, contributes to increasing energy efficiency. However, a significant content of esters of polyunsaturated acids, in particular Linolenic acid, methyl ester, reduces the resistance of biofuel to oxidation during long-term storage, which may require additional stabilization measures. The absence of by-products and impurities in the fraction indicates a high selectivity of the transesterification process.